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The field of cardiac electrophysiology (EP) had adopted simple artificial intelligence (AI) methodologies for decades. Recent renewed interest in deep learning techniques has opened new frontiers in electrocardiography analysis including signature identification of diseased states. Artificial intelligence advances coupled with simultaneous rapid growth in computational power, sensor technology, and availability of web-based platforms have seen the rapid growth of AI-aided applications and big data research. Changing lifestyles with an expansion of the concept of internet of things and advancements in telecommunication technology have opened doors to population-based detection of atrial fibrillation in ways, which were previously unimaginable. Artificial intelligence-aided advances in 3D cardiac imaging heralded the concept of virtual hearts and the simulation of cardiac arrhythmias. Robotics, completely non-invasive ablation therapy, and the concept of extended realities show promise to revolutionize the future of EP. In this review, we discuss the impact of AI and recent technological advances in all aspects of arrhythmia care., Graphical Abstract Artificial intelligence-enhanced arrhythmia care.

Precision Medicine (PM) is an innovative approach that, by relying on large populations’ datasets, patients’ genetics and characteristics, and advanced technologies, aims at improving risk stratification and at identifying patient-specific management through targeted diagnostic and therapeutic strategies. Cardiac channelopathies are being progressively involved in the evolution brought by PM and some of them are benefiting from these novel approaches, especially the long QT syndrome. Here, we have explored the main layers that should be considered when developing a PM approach for cardiac channelopathies, with a focus on modern in vitro strategies based on patient-specific human-induced pluripotent stem cells and on in silico models. PM is where scientists and clinicians must meet and integrate their expertise to improve medical care in an innovative way but without losing common sense. We have indeed tried to provide the cardiologist’s point of view by comparing state-of-the-art techniques and approaches, including revolutionary discoveries, to current practice. This point matters because the new approaches may, or may not, exceed the efficacy and safety of established therapies. Thus, our own eagerness to implement the most recent translational strategies for cardiac channelopathies must be tempered by an objective assessment to verify whether the PM approaches are indeed making a difference for the patients. We believe that PM may shape the diagnosis and treatment of cardiac channelopathies for years to come. Nonetheless, its potential superiority over standard therapies should be constantly monitored and assessed before translating intellectually rewarding new discoveries into clinical practice.

Aims Physical activity reduces cardiovascular disease burden and mortality, although its relationship with cardiac arrhythmias is less certain. The aim of this study was to assess the association between self-reported physical activity and atrial fibrillation (AF), ventricular arrhythmias and bradyarrhythmias, across the UK Biobank cohort. Methods and results We included 402 406 individuals (52.5% female), aged 40–69 years, with over 2.8 million person-years of follow-up who underwent self-reported physical activity assessment computed in metabolic equivalent-minutes per week (MET-min/wk) at baseline, detailed physical assessment and medical history evaluation. Arrhythmia episodes were diagnosed through hospital admissions and death reports. Incident AF risk was lower amongst physically active participants, with a more pronounced reduction amongst female participants [hazard ratio (HR) for 1500 vs. 0 MET-min/wk: 0.85, 95% confidence interval (CI) 0.74–0.98] than males (HR for 1500 vs. 0 MET-min/wk: 0.90, 95% CI 0.82–1.0). Similarly, we observed a significantly lower risk of ventricular arrhythmias amongst physically active participants (HR for 1500 MET-min/wk 0.78, 95% CI 0.64–0.96) that remained relatively stable over a broad range of physical activity levels between 0 and 2500 MET-min/wk. A lower AF risk amongst female participants who engaged in moderate levels of vigorous physical activity was observed (up to 2500 MET-min/wk). Vigorous physical activity was also associated with reduced ventricular arrhythmia risk. Total or vigorous physical activity was not associated with bradyarrhythmias. Conclusion The risk of AF and ventricular arrhythmias is lower amongst physically active individuals. These findings provide observational support that physical activity is associated with reduced risk of atrial and ventricular arrhythmias.

Atrial fibrillation (AF) is the most common cardiac arrhythmia and prevalence is predicted to double over the next 30 years due to changing demographics and the rise in prevalence of risk factors such as hypertension and diabetes. Atrial fibrillation is associated with a five-fold increased stroke risk, but anticoagulation in eligible patients can reduce this risk by around 65%. Many people with AF currently go undetected and therefore untreated, either because they are asymptomatic or because they have paroxysmal AF. Screening has been suggested as one approach to increase AF detection rates and reduce the incidence of ischaemic stroke by earlier initiation of anticoagulation therapy. However, international taskforces currently recommend against screening, citing the cost implications and uncertainty over the benefits of a systematic screening programme compared to usual care. A number of large randomized controlled trials have commenced to determine the cost-effectiveness and clinical benefit of screening using a range of devices and across different populations. The recent AppleWatch study demonstrates how advances in technology are providing the public with self-screening devices that are increasingly affordable and accessible. Health care professionals should be aware of the implications of these emerging data for diagnostic pathways and treatment. This review provides an overview of the gaps in the current evidence and a summary of the arguments for and against screening.

Background While cardiovascular complications, including arrhythmias are now a recognized manifestation of Multisystem inflammatory syndrome in children (MIS-C), there are no reports of primary bradycardia preceding the clinical presentation. We sought to describe a case series of sinus bradycardia as an initial manifestation of MIS-C. Methods We included a series of 10 consecutive patients with confirmed COVID-19 who met WHO and CDC criteria for MIS-C, who developed sinus bradycardia with a heart rate measured in the awake state that was below the normal range for age for children, as an initial manifestation of the disease, in a prospective observational multicenter study. Patients underwent clinical, laboratory evaluation, ECG, Holter, telemetry, echocardiogram, chest X Ray, and a chest CT scan. Results Of the 10 patients included, 6 were male, with a mean age of 6.52±5.35 years, range 4 months to 14 years. All cases were Hispanic. Bradycardia was transient and did not merit treatment. Coronary abnormalities were noted in 6 cases; 4 patients had mild coronary ectasia; 9 patients had pericardial effusion with no evidence of tamponade. All patients had a mild clinical course; none had shock, heart failure, the need for mechanical ventilation, or died. All blood markers (Troponin, BNP, Platelet count, C-reactive protein, D-dimer, Ferritin) returned to normal levels by discharge/follow-up with a favorable outcome including resolution of coronary dilatation in all but 2 in which aneurysm persisted. Treatment All patients received steroids and low-weight-molecular heparin 10 patients, 8 aspirin and 8 intravenous immunoglobulins. Conclusion Sinus bradycardia may be the initial manifestation of MIS-C, usually transient and mild. Physicians should be aware of this presentation. Funding Acknowledgement Type of funding sources: None. Kid, MIS-C. Bradycardia/Atrial Rhythm

Introduction Guidelines recommend transoesophageal echocardiography (TOE) before cardioversion in thrombogenic arrhythmias when the requirement of ≥3 weeks of anticoagulation is not met. Current data to support this approach, especially with direct oral anticoagulants (DOAC), are scarce. Methods We analysed consecutive elective pre-cardioversion TOE in a high-volume electrophysiology centre for the occurrence of LAA thrombi or reduced LAA flow velocity. Possible predictors were recorded and compared in a multivariate logistic regression analysis. Results Consecutive pre-cardioversion TOE in 512 patients (148 female, median age 69 years) were included. In all patients, indication for TOE was either intake of anticoagulation Conclusion The presence of LAA thrombus before an elective cardioversion is a rare event in the age of direct oral anticoagulants. However, LAA thrombi occurred even in supposed low-risk individuals according to the CHA2DS2-VaSc score. QRS width may aid in identifying patients at a high risk of a reduced LAA flow velocity. Funding Acknowledgement Type of funding sources: None. Figure 1. Representative images of a solid LAA thrombus (panel A), LAA sludge (panel B, not containing a solid thrombus on i.v. contrast imaging), and a LAA free of thrombus or sludge (panel C). Panel D shows the PW Doppler signal in a patient with LAA emptying velocity reduced ≤20cm/s while panel E shows a LAA with normal flow characteristics.

Background/Introduction Several ECG signs have been proposed to discern the focal origin of ventricular outflow tract arrhythmias with a transition ≥V3. Their independent predictive value is unclear. Purpose The aim of the study is to establish a predictive model of independent ECG parameters to obtain an acute success in right-sided catheter ablation of isolated premature ventricular contractions (PVCs) or ventricular tachycardia (VT) from the ventricular outflow tract with a transition ≥V3. Methods We included 122 patients (62 women, mean age 54±16 years) with documented PVCs or VT showing a lower axis and predominantly negative QRS complexes in V1 and V2 who underwent ablation between January 2014 and June 2020. The achievement of acute ablation success from right endocardial positions was assessed. We performed a predictive model by multivariate logistic regression analysis including the following ECG variables associated with a right origin of the ventricular focus in previous studies: Transitional Zone (TZ) index, V2 transition ratio, V2S / V3R index, R-wave duration index, R/S-wave amplitude index in V2, variable coupling interval, and the presence of QS morphology in lead I. Results Two independent predictive ECG variables were identified: the V2S / V3R index (odds ratio 1.223; 95% CI, 1.024–1.460; p=0.026) and a coupling interval variability >60 ms (odds ratio 0.307; 95% CI, 0.129 - 0.731; p=0.008). The area under the curve of this model was 0.733 (Picture 1). Arrhythmias with transition in V3 present a greater electroanatomic overlap and, therefore, a higher probability of right failure (59.3% vs 73.5% in arrhythmias with transitions after V3). In these, the V2 transition ratio is useful to predict the origin of the ectopy. Conclusion Two easily identifiable ECG variables (the V2S / V3R index and coupling interval variability >60 ms) predict the acute success of a right-sided approach in the ablation of focal ventricular arrhythmias with predominantly negative QRS complexes in V1 and V2. Funding Acknowledgement Type of funding sources: None. Predictive accuracy of the ECG model

The average effectiveness of electrical cardioversion in persistent atrial fibrillation (AF) is considered about 90%. The success is limited by arrhythmia longevity, essential heart pathology, excessive body mass, concomitant deceases. A novel developed in Russia class III intravenous medication “Refralon” (4-nitro-N-(1RS)-1(4-fluorophenyl)-2-(1-ethylpiperidin-4-ethyl) benzamide hydrochloride) seems to be promising in sinus rhythm restoration in such patients. The aim of the study was to assess the effectiveness of a novel class III intravenous medication “Refralon” in conversion to sinus rhythm in patients with permanent AF in whom electrical cardioversion was unsuccessful. Materials and methods 19 patients were included: 16 male and 3 female aged from 45 to 68 years old (59,9±5,84 (M±SD)). Left atrial size was 47±3,2 × 59±2,8 mm, BMI 38,5±7,0 kg/m2, arrhythmia duration from 2 to 21 months (6,7±4,99). Refralon was injected according to the approved manual in ICU; heart rhythm and rate, blood pressure, SpO2 were monitored. Dynamic assessment of QT and QRS duration was performed. Results In 17 of 19 patients (89,4%) sinus rhythm was restored. In 7 patients (41%) sinus rhythm was restored before 10 min, in 4 patients (24%) before one hour, in 4 patients (24%) before two hours, in 2 patients (11%) before six hours. In two patients sinus rhythm was not restored. In both target dose was not infused due to non-sustained ventricular tachycardia in one case, and QT prolongation in another. Conclusion In a small pilot study Refralon was highly effective in patients with persistent atrial fibrillation when electrical cardioversion was ineffective. All the patients had significantly increased BMI. The results may suggest the indication for Refralon usage in obese patients. Funding Acknowledgement Type of funding sources: None.

Introduction Three dimensional (3D) electroanatomical maps (EAMs) created during electrophysiology procedures are traditionally displayed on 2D monitors connected to mapping systems. This has limitations, such as the lack of interaction with EAMs, the need for another user to control them, and the size of EAM displayed, which is limited by the resolution of these monitors. To overcome these, we created a novel technology to display EAMs on a mixed reality (MR) platform. Methods We used the Microsoft® HoloLens to create this MR platform. Studies from patients who had already undergone catheter ablation for atrial fibrillation, where EAMs of the left atria had been generated using different mapping systems (CARTO®, Rhythmia™ and EnSite Precision™) were utilised. These EAMs consisting of 3D coordinates and annotations (e.g. voltage & activation times) were exported from the mapping system. EAMs were then compiled and transferred to the HoloLens using custom-developed functions on Unity©, Microsoft® C# and VisualStudio. Subsequently, feedback was obtained from 3 independent electrophysiologists on this technology. Results We successfully exported the EAMs generated on CARTO®, Rhythmia™ and EnSite Precision™ mapping systems as holograms on to the HoloLens (Figure). Positive feedback included themes such as 1) the ability to use hand gestures and voice commands to interact with EAMs independent of another user unlike traditional cardiac mapping systems 2) offering an interactive 3D holographic experience whilst preserving the operators' physical interaction in the cardiac catheter lab 3) the capacity to better appreciate 3D geometry of EAMs in comparison to 2D monitors. The challenge of wearing a headset during long procedures was perceived as a disadvantage. Conclusion This technology, which can be used with any mapping system, is currently optimised for offline display. Our software will be made available as an opensource teaching and simulation tool. Users will be able to explore EAMs for research, planning complex cases and immersive learning. The future directions will include extending this toolkit for real-time cardiac mapping with catheter localisation, and could potentially be translated to other cardiac imaging modalities. Funding Acknowledgement Type of funding sources: Public hospital(s). Main funding source(s): Cardiovascular diseases charitable fund (CDCF) at Guy's and St Thomas' NHS Foundation Trust. Process of creating Holograms of EAMsVoltage map of left atrium as a Hologram

Background Atrial Fibrillation (AF) is the most common arrhythmia, with important sequelae if left untreated. Markers help to predict the recurrence of AF after an intervention like ablation or electrical cardioversion (ECV). E/e' ratio is an echocardiographic marker which is potentially useful in predicting AF recurrence, however, present data is conflicting. Adding a simple tool like E/e' ratio to evaluation of patients for AF intervention may help in advising patients better about their risk for recurrent AF after intervention without adding much cost to the diagnostic work-up. Purpose To determine if there is a significant difference in pooled mean E/e' ratio among AF patients with recurrence after ablation or ECV compared to those who maintained sinus rhythm, and to determine the odds ratio of recurrent AF given an abnormal E/e' ratio. Methods The investigators systematically searched Pubmed, Medline, Cochrane Database, and Google Scholar for articles on patients undergoing catheter ablation or ECV for AF and who were adjudicated on recurrence of the arrhythmia. We calculated the weighted mean difference of E/e' ratio between those with recurring AF and those who maintained sinus rhythm, and the odds ratio of AF recurrence given an abnormal E/e' ratio. Statistical analysis was done using RevMan 5.4.1 software. Results A total of 38 studies involving 7048 patients were included in the initial analysis (26 studies on ablation with continuous data and 2 with dichotomous data based on a set cutoff, and 10 studies on ECV). One study was excluded due to absence of a blanking period and and another due to outlaying data in funnel plot analysis. The remaining 36 studies with 6910 patients were analyzed. There was a significant difference in the weighted mean E/e' ratio between the two groups in AF patients undergoing ablation (Mean Difference (MD)=0.60 (95% CI [0.20,1.00] p=0.003, I2=63%]), and ECV (MD=2.07 (95% CI [1.66, 2.49] p Conclusion This analysis suggests that a higher E/e' ratio may be used to predict recurrence of AF after ablation or ECV, especially in patients undergoing ECV. The heterogeneity of the data for E/e' ratio in AF ablation and the variety of co-morbid conditions to atrial fibrillation limits its clinical applicability. Further studies are recommended to determine the optimal cutoff of this ratio that would predict AF recurrence. Funding Acknowledgement Type of funding sources: None. Forest plot for studies on AblationForest plot for studies on ECV

Background Various devices are available for electrocardiogram (ECG) based home monitoring and could facilitate early detection of arrhythmias in adult congenital heart disease (ACHD). However, the diagnostic accuracy of these devices in ACHD is unknown. Purpose We aimed to determine the accuracy of different ECG-based devices compared to the standard 12-lead ECG in ACHD. Methods We performed a single-center, prospective, cross-sectional study in consecutive ACHD patients. We determined diagnostic accuracy of the Withings Scanwatch (lead I), Eko DUO (precordial ECG) and Kardia 6L (six leads) compared to the 12-lead ECG on several parameters: 1) automatic atrial fibrillation (AF) detection, 2) QRS-morphology assessment (simplified into normal (120ms) or other wide complexes (>120ms)), and 3) conduction times (PR, QRS, QTc time). All 12-lead and device ECGs were evaluated by a single observer. Results A total of 176 patients (54% male, age 40±16.6 years, 24% severe ACHD, 84% previous correction, six patients with AF) enrolled in the study. The Withings algorithm classified only 5% of ECGs as inconclusive compared to 31% of Kardia 6L (p Conclusions This is the first study to examine diagnostic accuracy of different ECG-based devices in ACHD. Overall, Withings Scanwatch may be the most practical choice for continuous AF screening while Kardia 6L could be preferred to accurately capture symptomatic palpitations. These findings can inform both patients and caregivers for optimal choice of home monitoring. Funding Acknowledgement Type of funding sources: None.

Background/Introduction The inspIRE clinical trial was designed to assess the safety and efficacy of a fully integrated biphasic pulsed field ablation (PFA) system comprised of a multi-channel generator, variable decapolar irrigated loop circular catheter, and mapping system (Figure A) for the treatment of paroxysmal atrial fibrillation (PAF). Purpose Using this novel PFA system in a multicentre clinical trial, we present the initial feasibility of electrical pulmonary vein isolation (PVI), procedural performance, and acute safety results. Methods inspIRE is a prospective, non-randomized, multi-centre study, planned to enrol up to 550 patients. PVI is performed with the novel, variable loop circular catheter, compatible mapping system and generator. Acute procedural effectiveness (entrance block in all clinically targeted PVs post adenosine/isoproterenol challenge) and the incidence of primary adverse events (PAEs) were assessed. PAEs are defined as the occurrence of cardiac tamponade/perforation, myocardial infarction, stroke/cerebrovascular accident, thromboembolism, transient ischemic attack, permanent phrenic nerve paralysis, pulmonary edema, pericarditis, and any major vascular access complications within 7 days of the ablation procedure. Additionally, any incidence of procedure or device related death, atrio-esophageal fistula, or PV stenosis (related to the ablation procedure or study catheter) within the 12M follow-up period is classified as a PAE. Results A total of 35 PAF subjects (age 59.7±10.7 years, 54.3% male) were treated across 5 European sites by 6 operators. Acute procedural success was achieved in 100% of study subjects (Figure B) with zero incidence of PAEs. Mean total procedure time was 82.9±19.9 minutes with 27.0±11.9 minutes of PFA from first to last application. Average fluoroscopy use was 10.6±6.8 minutes and LA dwell time was 45.6±15.3 minutes. Conclusion Initial results of the inspIRE trial demonstrate the acute safety and effectiveness of the new integrated IRE circular catheter, mapping system and generator for PVI in PAF patients. Funding Acknowledgement Type of funding sources: Other. Main funding source(s): inspIRE is a company-sponsored study funded by Biosense Webster, Inc. Figure 1. (A) PFA System; (B) PVI Voltage Map

Introduction Arrhythmogenic Cardiomyopathy (ACM) is a life-threatening entity which predispose to malignant arrhythmias and sudden cardiac death even in early stages of the disease. Deformation techniques obtained by echocardiography are promising tools which can identify subtle pathologic changes in the myocardial wall. Our aim is to investigate how myocardial deformation parameters may be affected throughout ACM spectrum. Methods A cohort of ACM 45 subjects, was characterized using advanced transthoracic echocardiography and divided into groups according to left ventricle ejection fraction (LVEF). Twenty-three healthy volunteers were also included as control group (CG). We analyzed regional wall motion abnormalities and left ventricular myocardial deformation parameters by 2D Speckle Tracking, such as global longitudinal strain (GLS), mechanical dispersion (MD) [standard deviation (SD) and range (delta)]. Results 23 (51,1%) of the ACM cohort were men, with a mean age of 43,13±16,55 years. Next-generation sequencing identified a potential pathogenic mutation in 37 (82,2%) of the patients. Those ACM subjects with low LVEF (ACM-L) presented lower GLS values when compared to those with normal LVEF (ACM-N) (−16,17±2,68% vs. ACM-N −19,39±2,97%; p Conclusions MD may be an additive tool for identifying ACM patients in early stages of the disease when LVEF is still preserved. Funding Acknowledgement Type of funding sources: None.

Background Sleep-disordered breathing (SDB) is often associated with atrial fibrillation, but detailed mechanisms remain elusive. Interestingly, late Na current (late INa) has been shown to be increased in patients with SDB, while expression of cardiac Na channel NaV1.5 and peak Na current were decreased. Indeed, recent data demonstrated that enhanced NaV1.8-dependent late INa may also induce pro-arrhythmic activity. Purpose We tested whether Na-V1.8 expression and subsequent NaV1.8-dependent pro-arrhythmic activity are increased in patients with SDB. Methods We prospectively analysed 29 right atrial appendage biopsies of patients undergoing elective coronary artery bypass grafting. SDB was assessed using polygraphy in the preoperative night and an apnoea-hypopnea index (AHI) ≥15/h defined SDB. Micro-dissected atrial trabeculae were electrically field stimulated (at 1 Hz, 5 V for 50 ms, at 37°C) to elicit regular contractions. Trabecular arrhythmias were induced using 100 nM isoproterenol at [Ca]o of 3.5 mmol/L and pro-arrhythmic activity was scored from 0 (no arrhythmias) to 5 (salve). Sarcoplasmic reticulum Ca leak was estimated by the contractility after paused stimulation (at 2 Hz, normalized to before pause). To correlate functional and expression data for each individual patient, NaV1.8 mRNA expression was quantified in each trabeculum using qPCR. Results NaV1.8 mRNA expression was increased in patients with SDB, leading to a significant positive correlation with the severity of SDB (i.e. AHI, p=0.02, r2=0.22, Fig. 1A). Multivariate regression analysis revealed that this association was independent from age, sex, atrial fibrillation, heart failure, diabetes mellitus, and renal function (p=0.03, r2=0.35). Accordingly, selective NaV1.8 blockade with PF-01247324 (PF, 1 μM, 30 min) significantly improved post-pause contractility of isolated trabeculae from 1.69±0.31 to 2.95±0.54 in patients with SDB (p=0.001), whereas no significant improvement was observed in patients without SDB. This resulted in significant positive correlations between the PF-dependent improvement of post-pause contractility and both AHI (p=0.047, r2=0.19) and NaV1.8 mRNA expression (p=0.03, r2=0.17). Most importantly, we also observed a significant increase in arrhythmia severity in patients with SDB of 2.21±0.52 (vs. 1.00±0.49, p=0.03) that could be significantly reduced by selective NaV1.8 inhibition with PF to 0.25±0.18 (p=0.0008, Fig. 1B). In accordance, there was a significant positive correlation between arrhythmia severity and AHI (p=0.01, r2=0.28) that was abolished in the presence of PF (interaction analysis: p=0.ehab724.33141, r2=0.46). Conclusion In patients with SDB, enhanced NaV1.8 expression contribute to atrial pro-arrhythmic activity independent from comorbidities. Selective NaV1.8 inhibition may have therapeutic implications for patients with SDB. Funding Acknowledgement Type of funding sources: Other. Main funding source(s): Part of the study was supported by grants from Philips Respironics (Murrysville, PA 15668) and the Medical Faculty at the University of Regensburg. Figure 1

Background There is limited published data on the use of implantable loop recorders (ILRs) in patients with long QT syndrome (LQTS). Purpose We sought to evaluate the utility of the ILR in patients who had a diagnosis of LQTS or who had a family history of LQTS. Methods We carried out a retrospective analysis of patients attending an Inherited Cardiac Conditions Clinic who had an active ILR and who had a diagnosis or family history of LQTS. Patient demographics, indications for ILR implantation and clinical outcomes were compiled. Results Nine patients with a diagnosis of LQTS and an active ILR were identified with an average age of 37 years. Genetic results were available for seven patients. Four patients had a confirmed pathogenic mutation (one KCNQ1 and three KCNH2), one patient had a variant of uncertain significance in SCN5A and two patients had negative genetic testing. Indications for implantation were syncope (n=4), recurrent altered consciousness episodes (n=1), assessment of occult arrhythmia or beta blocker complications (n=2), palpitations and dizziness (n=1) and nocturnal dyspnoea and palpitations (n=1). Mean follow-up was 706 days and average age at ILR implant was 35 years. The ILR for three patients was a second device, implanted after end of battery life of the initial ILR. ILR recordings led to a change in management in three patients: finding of paroxysmal atrial fibrillation (n=1), finding of nocturnal QTc of 511ms with a change in medications (n=1) and a pause leading to cessation of beta blocker (n=1). Eleven patients with a family history of LQTS and active ILR were identified. Nine patients were female, and the average age was 44.4 years. Genetic test results were available for five patients. Three patients had a pathogenic mutation in SCN5A, and two patients had negative genetic testing for common LQTS genes. Indications for implantation included syncope (n=5), lightheaded episodes (n=3) and risk assessment in gene carriers (n=3). The mean duration of ILR follow-up was 680 days and average age at ILR implant was 42.5 years. Five patients had no arrhythmia detected during ILR recording, two patients had supraventricular tachycardia identified, in two patients ILR data outruled a sinister cause for a symptomatic episode, one patient had documentation of SVT and brief NSVT which led to referral for electrophysiology study and one patient had no recurrence of symptoms and a second ILR was implanted. Conclusion ILRs were inserted in selected patients with a diagnosis of LQTS or in patients with a family history of LQTS or who were gene carriers. Rationale for ILR implantation included risk stratification, monitoring for occult arrhythmia and rhythm-symptom correlation in symptomatic patients. The ILR impacted management in almost 50% of patients and is considered an important tool in selected patients attending Inherited Cardiac Condition Clinics. Funding Acknowledgement Type of funding sources: None. Table 1

Background Primary cardiac tumors are extremely rare and are usually diagnosed late due to the nonspecific symptoms. Surgery is the main treatment option, and despite chemotherapy, the prognosis remains poor. Cardiac invasion by metastatic tumors, while more common, also entails an unsatisfactory outcome. The aim of this study was to review patients (P) with malignant cardiac tumors that were diagnosed by transthoracic echocardiogram (TTE) or transoesophageal echocardiogram (TOE) in a tertiary center between 1995 and 2020. Methods Retrospective analysis of clinical data, echocardiographic assessment of tumor location and morphology, histology results and survival outcomes. Results A total of 44 malignant cardiac tumors were diagnosed: 12 primary tumors (A) and 32 metastatic tumors (B). A: Regarding primary cardiac tumors, the most common types were angiosarcomas (6), undifferentiated pleomorphic sarcomas (2), fibrosarcomas (2), myxofibrosarcoma (1) and primary cardiac lymphoma (1). The mean age of P at time of diagnosis was 43±15 years, 50% male. The most frequent presentation was heart failure symptoms (50%) followed by arrhythmias (20%). 1 P presented with pruritus and polyarthralgias. On TTE, the most prevalent tumor location was in the right-heart chambers (70%) – mostly the right atrium (50%), with mean dimensions of 40±18x27±11 mm. 85% of P had preserved biventricular systolic function and there was severe pericardial effusion in 38%. The most frequent metastatic involvement at diagnosis was pulmonary (33%) and hepatic (33%). 50% of P were submitted to tumor resection and 40% to chemotherapy. Regarding angiosarcomas, the most common immunohistochemical markers were vimentin, CD31 and CD34. The authors found a mortality rate of 10P (83%) in P with primary cardiac tumors, with a median time to mortality of 5.5 (IQR 2–10) months (Figure 1), in a median follow-up of 6.2 (IQR 2.5–15) months (minimum of 20 days and maximum of 19 years). In the latter case, the P was submitted to heart transplantation after diagnosis of a fibrosarcoma and is still alive and well. B: Regarding secondary cardiac invasion, there was a diagnosis of the following primary tumor sites: 12 lung carcinomas, 7 thymomas, 4 lymphomas, 3 hepatocellular carcinomas, 2 bladder carcinomas, 1 parathyroid carcinoma, 1 soft tissue sarcoma, 1 uterine sarcoma and 1 melanoma. The mean age of P was 57±19 years, 57% male. On TTE/TOE the authors found a right-sided chambers predominance (12 P, 38%) vs left-sided chambers in (8 P, 25%), with pericardial metastasis also present in 13 P (41%). Cardiac tamponade occurred in 6P (19%). The mortality rate was 75% (24P), with a median time to mortality of 1.1 (IQR 0.6–3.8) months (minimum of 7 days, maximum of 44 months), in a median follow-up of 2.3 (IQR 0.8–14) months. Conclusion Cardiac malignant tumors generally present in a late stage with a dismal prognosis. When possible, heart transplantation can be an option with a favourable outcome. Funding Acknowledgement Type of funding sources: None. Figure 1. Kaplan-Meier analysis

Background/Introduction The rate corrected QT time (QTc) is the most commonly used ECG derived parameter to identify and risk-stratify inherited and acquired arrhythmia risk. Among the many potentially influencing factors, the female menstrual cycle has been described to lead to minor intra-individual changes, but the overall influence of sexual hormones on the QTc is incompletely understood. We therefore aimed to elucidate this relationship in hypertensive subjects. Purpose To identify confounding factors in QTc determination and elucidate potential endocrine causes of variable QTc time. Methods The Styrian Hypertension study is a cohort study aiming to identify novel cardiovascular risk factors. Subjects were recruited from a tertiary care center outpatient clinic. QTc was calculated according to Framingham and linear regression formulas adhering to the AHA/ACCF/HRS 2009 guideline for surface ECG interpretation. Plasma concentrations of estrone (E1), estradiol (E2), 17α-Hydroxyprogesterone and progesterone were measured by Biocrates AbsoluteIDQ Stero17 Kit. Patients on QTc altering medication were excluded from the present analyses. Results A total of 142 participants (mean [SD] age, 59.4 [11.7] years; 52% women, 80,1% post-menopause) were eligible for the present analyses. Linear regression analyses adjusted for potassium, HbA1c, NTproBNP and mean systolic blood pressure revealed only an association of QTc with progesterone (beta coefficient [95% CI]) of 0.38 [0.14 – 0.62] (P=0.002) in males. Detailed analyses revealed an U-shaped association. The other hormones showed no significant association in the present cohort of patients. Subgroups of premenopausal women and of patients without elevated blood pressure revealed no statistically significant results. Conclusions Contrary to previous evidence we found no sign. association between female sexual hormones and QTc time. We observed increased QTc time in males depending on their progesterone plasma concentrations, but the isolated finding may be a statistical outlier. Funding Acknowledgement Type of funding sources: None.

Background Atrial fibrillation (AF) is the most common sustained cardiac dysrhythmia and is associated with substantial morbidity and mortality. It can be managed either through ventricular rate control or conversion to sinus rhythm while for the patients with recent onset of AF, the latter is the recommended choice of treatment. Purpose To determine crude rates and the likelihood of conversion to sinus rhythm from recent-onset AF and mean difference in time to do so with respect if pharmacological cardioversion with propafenone or amiodarone is utilized. Methods MEDLINE and EMBASE electronic databases were searched and after exclusion criteria were applied, a total of 94 potential studies were identified, while 9 randomized controlled trials (RCTs) were included in the meta-analysis. These RCTs were conducted from 1994 until 2019 and investigated the use of oral/intravenous propafenone vs. amiodarone to convert recent-onset AF to sinus rhythm. The main outcome measures were a) likelihood of sinus rhythm restoration and for this analysis, an odds ratio (OR) with 95% confidence interval (95% CI) was reported, and b) mean time to sinus rhythm conversion between two treatment groups and the outcome measure for this endpoint was a mean difference (MD, in minutes). In both instances, OpenMeta[Analyst] software was used to perform meta-analysis while random-effects model was used with a restricted maximum likelihood-REML correction factor. Heterogeneity between RCTs was examined by the I2 test. Results A total of 9 RCTs pooled 822 patients, 410 randomized to propafenone and 412 to amiodarone treatment. All trials reported conversion rates while 7 trials reported on the time needed to reach sinus rhythm. Of these, only trials measuring conversion time during 12 to 24 hours were considered. Seven trials monitored patients for conversion during the 24 hours, one trial up until 12 hours, and 1 trial up to 8 hours. In most trials, recent-onset AF was defined as lasting ≤48 hours, and most were designed to perform intravenous drug comparisons. On average, conversion to sinus rhythm was achieved in 76.1% cases treated with propafenone and 71.8% cases treated with amiodarone. Propafenone use was non-significantly associated with a higher likelihood of conversion to sinus rhythm compared to amiodarone (OR 1.26, 95% CI 0.825–1.912) and there was a low degree of heterogeneity observed between trials (I2=34.9%, P=0.139; Figure 1). On the other hand, treatment with propafenone was associated with a significantly shorter mean time to sinus rhythm conversion compared to amiodarone (MD −304 minutes, 95% CI −342 to −266) and there was no heterogeneity observed between included trials (I2=2.78%, P=0.440; Figure 2). Conclusion Propafenone and amiodarone are similarly efficacious in converting patients from recent-onset atrial fibrillation to sinus rhythm, however, propafenone acts significantly faster and cuts mean time to sinus rhythm for about 5 hours. Funding Acknowledgement Type of funding sources: None. Figure 1. Odds ratio for conversion to SRFigure 2. Mean difference in minutes to reach SR

There is a general notion that the COVID pandemic has made access to adequate health care difficult. A retrospective study looked at patients with acute myocardial infarction (AMI) admitted to a hospital, including the time between admission and diagnosis, the time until treatment, and the delay in transferring to a hospital with a catheterization laboratory in the case of ST-Elevation Myocardial Infarction (STEMI).The period analysed was March to July 2019 and March to July 2020 (first Covid pandemic wave). 197 patients, 101 in 2019 (SCA19) and 96 in 2020 (SCAcov), 142 males (72%) mean age 67.3±12.6. It was observed in 2019 29 STEMI and 72 acute myocardial infarct without ST elevation (NSTEMI) na 2020 36 STEMI and 60 NSTEMI, this proportions didn't achieve statistical meaning χ2(1)=1.719, p=0.226. When compared SCA19 versus SCAcov there were no differences between groups in relation to demographic data. The clinical presentation (none, hemodynamic instability, refractory pain, arrhythmia, mechanic complication, acute heart failure) not varied between groups χ2(6)=3.42, p=0.755. When analysed, between SCA19 and SCAcov, there were no significant time difference between the admission and the electrocardiogram execution (MSCA19 = 44.78; MSCAcov = 56.84; Tweich (132.66) = −0.73, p=0.476 g Hedge = 0.71, between time of admission and time of diagnosis MSCA19 = 264.84; MSCAcov = 254.2; Tweich (188.81) = −0.34, p=0.731 g Hedge = 0.05, and the duration of hospitalization MSCA19 = 5.90; MSCAcov = 5.78 U=9400, Z=−0.263, p Conclusion In COVID times even with the all restrictions and contingencies lived in hospitals our results pointed to no significant changes in the variables analysed. Interestingly, in spite of no significant difference, a slightly more delay in ECG execution, higher prevalence of STEMI but a short time of diagnosis were observed. Funding Acknowledgement Type of funding sources: None.

Background There is an increasing number of smartwatches and devices commercially available that can generate and automatically interpret an electrocardiogram (ECG). Such devices have an enormous potential to improve population screening and telemonitoring of atrial fibrillation (AF). Purpose There is limited data on the sensitivity, specificity and interpretability of these devices and comparative studies are lacking. Our purpose was to compare three frequently used devices for AF detection. Methods We performed a single-center, prospective study in consecutive patients with AF presenting for electrical cardioversion (ECV). We collected a standard 12-lead ECG recording immediately followed by four times 30 seconds of ECG recordings from different devices for every patient prior to the ECV. These paired measurements were considered simultaneous. If the ECV was performed, the same measurements were repeated afterwards. The standard 12L-ECGs were interpreted by a cardiologist and used as golden standard for heart rhythm. The different devices used for the 30 second ECGs were: Withings Move ECG (lead I), Apple Watch series 5 (lead I), Kardia Mobile 6L (six leads) and Withings/Apple (1:1 ratio) on left knee (lead II). Sensitivity and specificity were determined for each AF detection algorithm excluding patients with atrial flutter (AFL) or uninterpretable ECGs. In addition, proportions of uninterpretable ECGs were determined including all patients and including only patients with sinus rhythm (SR) and compared between devices using McNemar's test. Results A total of 220 patients were included (age 70±10 years, female 35%, first ECV 44%) and in total 415 12-lead ECGs were performed (45% SR, 45% AF, 10% AFL). The sensitivity/specificity were overall similar for all devices (Withings 98%/95%, Apple 94%/98%, Kardia 99%/91%. P>0.05 for all). In detail, Kardia was the most sensitive test with highest proportion of suspected AF (57%) whereas Apple was the most specific, as shown by the highest proportion of normal heart rate results by the device (55%, P=0.003 compared to Kardia (43%)). Overall, Withings, Apple and Kardia had a comparable proportion of uninterpretable ECGs (20%, 20%, 24%, respectively. P>0.05 for all). Lead II had higher proportion of uninterpretable ECGs (32%, p Conclusion In all devices, we found sensitivity/specificity for AF detection between 91%-99%, better than previous studies reported, and 20–24% of uninterpretable ECGs. Kardia was the most sensitive device, but less useful to rule out atrial fibrillation whereas Apple had numerically highest specificity. We aim to further evaluate both cardiologist interpretation and accuracy of atrial flutter detection using different leads to inform clinical use. Funding Acknowledgement Type of funding sources: Public hospital(s). Main funding source(s): Tergooi Cardiology department, J.P. Bokma was supported with a research grant by Amsterdam Cardiovascular Sciences Overview and comparison

Aims The aim of this study was to examine the effect of dapagliflozin on the incidence of ventricular arrhythmias and sudden death in patients with heart failure and reduced ejection fraction (HFrEF). Methods and results In a post hoc analysis of DAPA-HF, we examined serious adverse event reports related to ventricular arrhythmias or cardiac arrest, in addition to adjudicated sudden death. The effect of dapagliflozin, compared with placebo, on the composite of the first occurrence of any serious ventricular arrhythmia, resuscitated cardiac arrest, or sudden death was examined using Cox proportional hazards models. A serious ventricular arrhythmia was reported in 115 (2.4%) of the 4744 patients in DAPA-HF (ventricular fibrillation in 15 patients, ventricular tachycardia in 86, ‘other’ ventricular arrhythmia/tachyarrhythmia in 12, and torsade de pointes in 2 patients). A total of 206 (41%) of the 500 cardiovascular deaths occurred suddenly. Eight patients survived resuscitation from cardiac arrest. Independent predictors of the composite outcome (first occurrence of any serious ventricular arrhythmia, resuscitated cardiac arrest or sudden death), ranked by chi-square value, were log-transformed N-terminal pro-B-type natriuretic peptide, history of ventricular arrhythmia, left ventricular ejection fraction, systolic blood pressure, history of myocardial infarction, male sex, body mass index, serum sodium concentration, non-white race, treatment with dapagliflozin, and cardiac resynchronization therapy. Of participants assigned to dapagliflozin, 140/2373 patients (5.9%) experienced the composite outcome compared with 175/2371 patients (7.4%) in the placebo group [hazard ratio 0.79 (95% confidence interval 0.63–0.99), P = 0.037], and the effect was consistent across each of the components of the composite outcome. Conclusions Dapagliflozin reduced the risk of any serious ventricular arrhythmia, cardiac arrest, or sudden death when added to conventional therapy in patients with HFrEF. Clinical trial registration ClinicalTrials.gov unique identifier: NCT03036124 (DAPA-HF)., Graphical Abstract DAPA-HF: trial design and main findings. BMI, body mass index; BP, blood pressure; CI, confidence interval; HF, heart failure; HFrEF, heart failure and reduced ejection fraction; HR, hazard ratio; LVEF, left ventricular ejection fraction; MI, myocardial infarction; NT-proBNP, N-terminal pro-B-type natriuretic peptide.

Aims Direct-current cardioversion is one of the most commonly performed procedures in cardiology. Low-escalating energy shocks are common practice but the optimal energy selection is unknown. We compared maximum-fixed and low-escalating energy shocks for cardioverting atrial fibrillation. Methods and results In a single-centre, single-blinded, randomized trial, we allocated elective atrial fibrillation patients to cardioversion using maximum-fixed (360-360-360 J) or low-escalating (125-150-200 J) biphasic truncated exponential shocks. The primary endpoint was sinus rhythm 1 min after cardioversion. Safety endpoints were any arrhythmia, myocardial injury, skin burns, and patient-reported pain after cardioversion. We randomized 276 patients, and baseline characteristics were well-balanced between groups (mean ± standard deviation age: 68 ± 9 years, male: 72%, atrial fibrillation duration >1 year: 30%). Sinus rhythm 1 min after cardioversion was achieved in 114 of 129 patients (88%) in the maximum-fixed energy group, and in 97 of 147 patients (66%) in the low-escalating energy group (between-group difference; 22 percentage points, 95% confidence interval 13–32, P Conclusion Maximum-fixed energy shocks were more effective compared with low-escalating energy shocks for cardioverting atrial fibrillation. We found no difference in any safety endpoint.

Aims The term idiopathic ventricular fibrillation (IVF) describes survivors of unexplained cardiac arrest (UCA) without a specific diagnosis after clinical and genetic testing. Previous reports have described a subset of IVF individuals with ventricular arrhythmia initiated by short-coupled trigger premature ventricular contractions (PVCs) for which the term short-coupled ventricular fibrillation (SCVF) has been proposed. The aim of this article is to establish the phenotype and frequency of SCVF in a large cohort of UCA survivors. Methods and results We performed a multicentre study including consecutive UCA survivors from the CASPER registry. Short-coupled ventricular fibrillation was defined as otherwise unexplained ventricular fibrillation initiated by a trigger PVC with a coupling interval of Conclusion Short-coupled ventricular fibrillation is a distinct primary arrhythmia syndrome accounting for at least 6.6% of UCA. As documentation of ventricular fibrillation onset is necessary for the diagnosis, most cases are diagnosed at the time of recurrent arrhythmia, thus the true prevalence of SCVF remains still unknown. Quinidine is effective in SCVF and should be considered as first-line treatment for patients with recurrent episodes.

Background Atrial fibrillation (AF) is a common arrhythmia with significant morbidity due to an increased risk of ischemic stroke. Outpatient electrocardiogram (ECG) monitoring is an integral part of the diagnosis of AF. Conventional 24 hour Holter monitoring can be cumbersome and often fails to diagnose patients with paroxysmal AF. Spyder ECG is a non-invasive ECG monitoring device that allows wireless transmission of ECG information for analysis. It is small and comfortable, allowing for easy application for the screening and detection of AF over a mid-term duration. Purpose This study aims to evaluate the incidence of AF in patients with no prior AF and CHADsVASC score of at least 1 with the use of the Spyder ECG mid-term ECG monitoring device. Methods Patients aged 21 to 85 years old with no prior history of AF and CHADsVASC score of at least 1 were recruited from outpatient clinics of 3 large tertiary hospitals in Singapore from December 2016 to April 2019. Patients wore the Spyder ECG device for up to 2 weeks, during which continuous ECG information was uploaded onto a central cloud database and analysed. Results There were 363 patients recruited. The mean age was 61±10.0 years and 65.1% were male. There were 80.3% Chinese, 11.6% Malay, 7.5% Indian and 20.6% of other races. 68.3% of the patients were non-smokers and 74.0% of them were non-alcohol drinkers. The mean BMI of 25.5±4.7 kg/m2. The patient population had significant co-morbidities. 76.3% of the patients had hypertension, 69.4% of them had hyperlipidemia and 40.5% of them had diabetes mellitus. 10.0% of them had congestive cardiac failure and 56.7% had ischaemic heart disease. 11.3% of patients had a previous stroke and 20.4% had a prior myocardial infarction. 7.8% of the patients had asthma, 5.8% of them had thyroid disease and 9.9% of them had chronic kidney disease. They were monitored for a mean of 5.4±2.9 days each. There were 15 (4.1%) patients in whom AF was detected. The patients with AF wore the device for a mean of 5.7±2.0 SD days. The mean burden of AF was 9.0% of monitored time. 46.7% of the patients with AF had detection of AF on the first day, 26.7% on the second day, 13.3% on the third day and 13.3% on the seventh day. The mean duration of the first episode of AF was 251±325 minutes. 7 out of 15 (46.7%) of patients had first episodes of AF lasting less than 10 minutes. Conclusion Continuous mid-term ECG monitoring was able to detect AF in 15 (4.1%) of a population of 363 patients with no prior AF and CHADsVASC score of at least one, monitored for a mean of 5.4 days. Most episodes (53.3%) of AF were detected after the first day of ECG monitoring. Funding Acknowledgement Type of funding source: Public Institution(s). Main funding source(s): Duke-NUS Medical School Singapore

There is an ongoing debate regarding the use of beta blockers (BB) in heart failure with preserved or intermediate ejection fraction. Most studies with BB included patients with moderate to severe left ventricle (LV) dysfunction and some trials challenge the assumption that BB are an effective therapy in these patients. Furthermore, there are some causes of heart failure where the use of BB is not well defined, particularly patients with DCM and mildly reduced LV ejection fraction. Our objective was to analyze the use of beta blockers in patients with dilated cardiomyopathy and to assess its relationship with LV or right ventricle (RV) ejection fraction, late gadolinium enhancement and cardiovascular events (CVE). A retrospective, case control study was designed including 173 patients (mean age 60 years, 73% males, 36% dyslipemia, 30% diabetes, 20% hypertension, 8% currents smoker, 12% previous atrial fibrillation) with diagnosis of DCM and CMR study in our center between 2014–2020 according to the latest European Society of Cardiology (ESC) definition and the latest updated position paper. Clinical data, use of guideline directed medical therapy and devices, cardiac imaging tests, mortality and CVE were collected and analyzed. After a mean follow up of 18 months, 53 patients (30%) suffered a CVE (16% heart failure, 14% incident arrythmia, 0.5% stroke 8% death). The use of beta blockers (n=152; 87%) was associated with a reduced risk for arrythmias (OR=0.019; p=0.0006) in a univariate analysis. It was not associated with RV ejection fraction (p=0.3), hospitalization for heart failure (p=0.03), mortality (p=0.26), or late gadolinium enhancement (p=0.8). For multivariate analyses (log regression, multiple linear regression) we adjusted for age, cardiovascular risk factors, medications, presence of atrial fibrillation, use of devices, LV and RV ejection fraction and presence of late gadolinium enhancement. In our multivariate analyses the use of beta blockers was an independent predictor of improved left ventricle ejection fraction (5.8% mean; p=0.009) and was associated with a marked decrease in the risk of incident arrythmias (OR=0.028; p=0.002) and in mortality (OR=0.068; p=0.041). In patients with DCM, the use of beta blockers is associated with improved LV ejection fraction and a statistically significant reduction in mortality and incident arrythmias. Beta blockers should be recommended irrespective of LV ejection fraction in order to decrease morbidity and mortality in patients with dilated cardiomyopathy. Further studies should assess the contribution of beta blockers in specific etiologies of dilated cardiomyopathy where they could be most helpful and could help to identify the best candidates for early initiation of heart failure therapy. Funding Acknowledgement Type of funding source: None

Background The infrequent nature of syncope can make diagnosis of cardiac pauses challenging with conventional monitoring (CM) strategies of intermittent external short-term ECG monitoring. Insertable cardiac monitors (ICMs) continuously monitor for arrhythmias and are well-established to have a higher likelihood of diagnosis compared to CM. It is not well understood whether the higher up-front cost of ICM is offset by the cost of repeat evaluation in a CM strategy, per diagnosed patient. Purpose The objective of this analysis was to simulate the cost per patient diagnosed with pause arrhythmias, between various CM strategies and ICM monitoring. Methods ICM device data from syncope patients was utilized to simulate patient pathways with CM. We assumed that detected true pause episodes (≥5 seconds) were symptomatic and prompted further evaluation: simulated inpatient or outpatient emergency department (ED) assessment, followed by external ECG monitoring of varying durations (24 or 48 hours, 14 or 30 days, or two 30-day monitors) beginning at random within the week after discharge. Subsequent true pause episodes in yet undiagnosed patients triggered additional rounds of CM. ECG diagnosis was considered successful if a pause episode occurred on the same day as simulated CM. Costs of evaluation and monitoring were accrued at each encounter. Inpatient and outpatient (ED) syncope evaluation costs (mean £3,746 and £367, respectively) were based on national episode statistics data and national average tariffs, and simulated at random from log-normal distributions; costs of external ECG monitors and ICM (including ICM device, insertion, remote monitoring, and explant) were fixed. Costs stopped accruing once a patient was diagnosed. We computed costs per diagnosed patient by dividing the total costs accrued for all patients by the number of patients diagnosed across 1,000 simulations. Longer pause definitions of ≥6–7 seconds were also evaluated. Results A total of 105 true pause episodes from 44 patients (mean (SD) age 66 (17), 48% male) were detected by ICM during 505 (333) days of follow-up. Patients experienced an average of 2.4 (2.7) pause episodes ≥5 seconds during follow-up. Relative to ICM-diagnosed patients, CM diagnosed between 13.8% (24-hour holter) to 30.2% (two 30-day monitors) of these patients. Cost per ICM-diagnosed patient was £2,985, whereas in the CM strategies the average cost per diagnosed patient ranged from £18,519 (£7,603) with 24-hour holter to £5,656 (£890) for two 30-day monitors (Figure). Costs per diagnosed patient further increased for pause durations of ≥6–7s, as the percent of patients diagnosed via CM decreased. Conclusion Relative to syncope patients diagnosed with pause arrhythmias via ICM, CM strategies diagnose fewer patients and incur significantly greater costs per diagnosed patient. Real-world suboptimal patient compliance with external monitoring would further decrease the cost-effectiveness of CM. Funding Acknowledgement Type of funding source: Private company. Main funding source(s): Medtronic

Background Epicardial adipose tissue (EAT) has recently been shown to be associated with the presence, severity, and recurrence of atrial fibrillation (AF). Although the pathophysiological mechanisms underlying this association remain to be established, several hypotheses have been put forward, including direct adipocyte infiltration, oxidative stress, and the secretion of adipokines causing inflammation and fibrosis of atrial tissue. We hypothesized that the volume of EAT and the amount of left atrium (LA) fibrosis assessed by non-invasive imaging would be significantly correlated in patients with AF, and that both would predict time to relapse after pulmonary vein isolation (PVI). Methods Sixty-eight patients with AF being studied for a first PVI procedure underwent both cardiac computerized tomography (CT) and cardiac magnetic resonance (CMR) within less than 48h. EAT was quantified on contrast-enhanced CT images. LA fibrosis was quantified on isotropic 1.5mm 3D delayed enhancement CMR for image intensity ratio values >1.20. Radiofrequency PVI was performed using an irrigated contact force-sensing ablation catheter, guided by electroanatomical mapping. After PVI, patients were followed for AF recurrence, defined as symptomatic or documented AF after a 3-month blanking period. Pearson's correlation coefficient was used for gauging the correlation between EATLM volume and LA fibrosis. The relationship between these two variables and time to AF recurrence was assessed by Cox regression. Results Most of the 68 patients (46 men, mean age 61±12 years) had paroxysmal AF (71%, n=48). The mean body mass index (BMI) was 28.0±4.0 kg/m2. Patients had a median EATLM volume of 2.4 cm3/m2 [interquartile range (IQR) 1.6–3.2 cm3/m2], and a median estimated amount of LA fibrosis of 8.9 g (IQR 5–15 g), corresponding to 8% (IQR 5–11%) of the total LA wall mass. The correlation between EATLM and LA fibrosis was statistically significant but weak (Pearson's R = 0.38, P=0.001) – Figure 1. During a median follow-up of 22 months (IQR 12–31), 31 patients (46%) suffered AF recurrence. Four predictors of relapse were identified in univariate Cox regression: EATLM (HR 2.19, 95% CI 1.65–2.91, P Conclusion The weak correlation between EAT and LA suggests that LA fibrosis is not the main mechanism by which EAT and AF are linked. EAT was more strongly associated with AF recurrence than LA fibrosis, which supports the existence of other, more important mediators between EAT and this arrhythmia. Correlation between EAT and LA Funding Acknowledgement Type of funding source: None

Atrial fibrillation (AF) is a common complication in acute coronary syndrome (ACS). However, treating patients (pts) with new-onset AF (NOAF) after an ACS remains a challenge. Although it seems intuitive that pts who develop AF within the first 48h have increased morbidity and mortality, your prognosis is unclear because there are no robust studies in the literature to confirm this association. Aim To characterize the population of pts who developed NOAF in the first 48 hours after an ACS and to compare the prognosis between these pts and pts who didn't develop AF. Methods 2916 ACS pts admitted consecutively in our coronary care unit during 6 years were analyzed retrospectively. Of these pts, 343 (11.7%) had AF within the first 48h, of which 99 (3.4%) had pre-existing AF and 243 (8.3%) presented NOAF. Pts were divided into two groups: group 1 -ACS pts who developed NOAF in the first 48h (n=243; 8.8%); group 2 – ACS pts who did not develop AF (n=2517; 91.2%). Pts with pre-existing AF were excluded (n=156; 5.4%). Primary endpoint were the occurrence of death at 6 months; follow-up was completed in 95.8% of pts. Results Group 1 pts were older (72±12 vs 62±13, p1 (OR 1.51, p=0.015) remained independent predictors of NOAF. In multivariate analysis and after adjusting for different baseline characteristics, pts with NOAF have the same risk of 6-months mortality compared to those who didn't develop AF [OR 1.03, p=0.91]. Conclusion The incidence of NOAF was 8.8% in our population, which is similar to the literature. Age, LVEF, LA diameter, a significant mitral regurgitation and Killip class >1 were independent predictors of NOAF after ACS. Pts with NOAF in the first 48h after an ACS had worse clinical manifestations during hospitalization but no higher 6-months mortality risk. Funding Acknowledgement Type of funding source: None

Background The identification of patients still in sinus rhythm who will present one month later an atrial fibrillation episode is possible using machine learning (ML) techniques. However, these new ML algorithms do not provide any relevant information about the underlying pathophysiology. Purpose To compare the predictive performance for forecasting AF between a machine learning algorithm and other parameters whose pathophysiological mechanisms are known to play a role in the triggering of arrhythmias (i.e. the count of premature beats (PB) and heart rate variability (HRV) parameters) Material and methods We conducted a retrospective study from an outpatient clinic. 10484 Holter ECG recordings were screened. 250 analysable AF onsets were labelled. We developed a deep neural network model composed of convolutional neural network layers and bidirectional gated recurrent units as recurrent neural network layers that was trained for the forecast of paroxysmal AF episodes, using RR intervals variations. This model works like a black box. For comparison purposes, we used a “random forest” (RF) model of ML to obtain forecast results using HRV parameters with and without PB. This model allows the evaluation of the relevance of HRV parameters and of PB used for the forecast. We calculated the area under the curve of the receiving operating characteristic curve for the different time windows counted in RR intervals before the AF onset. Results As shown in the table, the forecasting value of the deep neural network model (ML) was not superior to the random forest algorithm. Prediction value of both decreased when analyzing the RR intervals further away from the onset of AF Conclusions These results suggest that HRV plays a predominant role in triggering AF episodes and that premature beats could add minor information. Moreover, the closer the window from AF onset, the better the accuracy, regardless of the method used. Such detection algorithms once implemented in pacemakers, might prove useful to prevent AF onset by changing pacing sequence while patients would still be in sinus rhythm, however this remains to be demonstrated Funding Acknowledgement Type of funding source: None

Background Induction of atrial fibrillation (AF)/atrial tachycardia (AT) by atrial burst pacing following ablation procedure may reflect the presence of residual substrates in the atria that maintain AF. However, the relation between the inducibility and left atrial low voltage area (LVA) has not been established. Methods Fifty-nine patients (65 years old, 43 males) with persistent AF who underwent pulmonary vein isolation (PVI)-based ablation were studied. All patients underwent left atrial voltage mapping during sinus rhythm and atrial burst pacing after PVI. Atrial burst pacing was performed with 30-beat at an amplitude of 10V from the ostium of the coronary sinus; increasing from 240 to 320 ppm in steps of 20 ppm or failure to 1:1 atrial capture. Inducibility was defined as AF/AT lasting more than 5 minutes following burst pacing. Left atrial LVA and other co-variates were analyzed with regard to burst pacing positivity. Results AF/AT was induced by burst pacing in 23 patients (39%). Univariate analysis revealed that past history of stroke, CHADS2 score and presence of left atrial LVA were significantly associated with the inducibility of AF/AT. Multivariate analysis revealed that only the presence of LVA was associated with the inducibility (OR 1.5: per 10% increase; p=0.04). We focused on the relationship between the extent of LVA and burst positivity. AF/AT inducibility increased as low voltage area increased, and it was as high as 72.7% when low voltage area was more than 20% (P Conclusions Presence of left atrial LVA is an independent predictor of atrial tachyarrhythmia inducibility after PVI in patients with persistent AF. A large amount of low voltage area is related to AT inducibility rather than AF. Extent of LVA and burst positivity Funding Acknowledgement Type of funding source: None

Background and purpose European and American cardiovascular treatment guidelines advocate for two and three years of beta-blocker (BB) treatment, respectively, following myocardial infarction (MI). Contemporary continued efficacy of longer-term use of BB in stable coronary artery disease has been debated in the era of reperfusion. We aim to investigate the cardio-protective effect associated with BB treatment in patients following MI. Methods Using nationwide databases, we included optimally treated patients with first-time MI undergoing coronary angiography (CAG) or percutaneous coronary intervention (PCI) during admission and treated with both acetyl-salicylic acid and statins post-discharge between 2003 and 2017. Patients with prior history of MI, BB use or any other possible indication or contraindication for BB treatment (heart failure, cardiac arrhythmias or procedures, asthma, chronic obstructive pulmonary disease) were excluded. Continued BB exposure was defined as two redeemed prescriptions within the first 180 days following discharge, one of them within 90 days. Follow-up began 180 days following discharge in patients alive and with no further cardiovascular events or procedures prior. Patients were followed for a maximum of three years. Primary outcomes were cardiovascular death and recurrent MI in patients stratified by BB treatment using adjusted Cox regression models. Results A total of 27,068 patients optimally treated for MI were included (57% acute PCI, 26% sub-acute PCI, 17% CAG without intervention). At study start 180 days following MI, 79% of the patients were on BB treatment (median age 61 years, 75% male) and 21% were not (median age 62 years, 69% male). Cumulative incidence of cardiovascular death and recurrent MI did not differ significantly comparing patients on BB treatment with patients not on BB treatment (Figure). In multivariable analyses, BB treatment was associated with a similar risk of cardiovascular death and recurrent MI compared to the patients not receiving BB treatment (hazard ratios with [95% confidence intervals] correspondingly; 0.89 [0.68–1.17] and 1.02 [0.89–1.18]) (Figure 1). When stratifying the cohort according to calendar year and type of procedure during admission, we found similar results as the main analysis. No interaction for sex was found. Conclusions In this nationwide cohort study of optimally treated patients following MI at 180 days in the reperfusion era, we found a very good prognosis with only 1.2% suffering cardiovascular death and 4.7% suffering a recurrent MI within three years. In total 79% of patients were receiving BB treatment, but we found no difference suggesting BB to be associated with an improved cardiovascular prognosis. These findings challenge current clinical practice and guideline recommendation, suggesting that the role of long-term BB use may be obsolete among optimally treated MI patients. Further investigations, preferably a randomized trial, are warranted. Figure 1 Funding Acknowledgement Type of funding source: Foundation. Main funding source(s): Ib Mogens Kristiansens Almene Fond, Snedkermester Sophus Jacobsen og Hustru Astrid Jacobsens Fond

Background Intracardiac electrogram data remain one of the primary diagnostic inputs guiding complex ablation procedures. However, the technology to collect, process, and display intracardiac signals has remained relatively unchanged for the past two decades. Purpose We test a new platform, the PURE EP™ 2.0 system (PEP; BioSig Technologies) for signal processing and display. Methods Identical electrocardiographic and intracardiac signal data were recorded during 15 AF ablation procedures from the PEP system, the signal recording system, and the 3D mapping system (Figure). The collected signals underwent blinded, controlled evaluation by three independent electrophysiologist reviewers to determine whether the PEP signals are a viable alternative to conventional sources and if it provides additional or clearer diagnostic information. Reviewers were asked to record the quality of each signal sample on a scale of 1–10 and select a rationale for their rating in a dropdown menu. Each paired signal rating was collected and unblinded for the analysis. If the reviewer rated the samples in the set within 1 point of each other, the PEP sample was deemed equivalent to the control. Using a 2+1 statistical method, the ratings from the three reviewers were then compared looking for at least two positive reviews for each PEP sample. Results Based on the ratings for each pair of signals, a cumulative total of 29 PEP signals out of 34 (85.3%) were rated as statistically equivalent or better for this dataset. In 35.5% of samples, the reviewers selected PEP because “more signal components were visible”. Conclusion The PURE EP 2.0 system is able to produce reliable and high-quality signals when compared to available standard of care systems. Further studies with larger dataset across multiple sites are needed to validate these results. Funding Acknowledgement Type of funding source: Private company. Main funding source(s): BioSig Technologies

Background Digoxin is one of the oldest cardiovascular medications still used to treat heart failure and atrial fibrillation. Due to its narrow therapeutic window, it is associated with life threatening intoxication and arrhythmias, and with QTc-shortening. Common genetic variation in the nitric oxide synthase-1 adaptor protein (NOS1AP) has been associated with QTc interval prolongation. Purpose We investigated whether the rs10494366 variant of the NOS1AP gene modified the risk of SCD in patients using digoxin. Methods In a prospective population-based cohort study, we included data of the three cohorts, started as of January 1st, 1991 until January 1st 2014. Digoxin current use on the date of cardiac death in cases and the same day of follow-up in the remainder of the cohort was a time-dependent exposure. The main outcome was SCD defined as sudden and unexpected death as a result of cardiac causes, according to international criteria. Identification and adjudication of SCD was performed independently, before the start of this study. We used Cox proportional hazard regression analysis to investigate the associations between NOS1AP rs10494366 variant and incident SCD among digoxin users compared to non-users. Associations were adjusted for age, sex (model 1) in addition to BMI, prevalent diabetes, myocardial infarction, baseline hypertension and smoking status (past, current, never) (model 2). Results We included 14,594 individuals, with a mean age of 65.3 (SD 10.3) years. Almost 59% were female. The cumulative incidence of SCD was 9.5% (609 cases) by the end of follow up. Among them, 98 (16%) individuals were exposed to digoxin at the time of death. In model 1, NOS1AP rs10494366 variant was not associated with SCD in the total study population. However, an interaction term of the gene with the daily dose of digoxin was significantly associated with increased risk of SCD (p-value 0.0001). In model 2, the risk of SCD in current users of digoxin was 4.2 [95% CI 1.3–13.8] for the GG genotype; 2.1 [95% CI 1.1–4.2] for the GT genotype, and 1.5 [95% CI 0.7–3.2] for the TT genotype. Conclusion NOS1AP rs10494366 variant modified the risk of sudden cardiac death in users of digoxin. Our study suggests that individuals with the homozygous minor GG allele have a fourfold increased risk of sudden cardiac death. Funding Acknowledgement Type of funding source: None

Background Cardiac disease is one of the major causes of maternal mortality. We studied pregnancy outcomes in women with a systemic right ventricle (sRV) after the atrial switch procedure for transposition of the great arteries (TGA) or congenitally corrected TGA (CCTGA). Methods The ESC-EORP Registry of Pregnancy and Cardiac Disease is an international prospective registry of pregnant women with cardiac disease. Pregnancy outcomes (maternal and fetal) in women with a sRV are described. The primary endpoint was a major cardiovascular event (MACE) defined as maternal death, supraventricular or ventricular arrhythmias requiring treatment, heart failure, aortic dissection, endocarditis, ischemic coronary event and other thromboembolic events. Results Altogether, 163 women with a sRV (TGA n=121, CCTGA n=42, mean age 28.8±4.6 years) were included. Maternal mortality did not occur. At least one MACE occurred in 26 women (heart failure in 16 (9.8%), arrhythmias (atrial 5, ventricular 6) in 11 (6.7%), and others in 4 (2.5%)). Predictors of MACE were pre-pregnancy signs of heart failure [Odds ratio (OR) 6.05, 95% CI: 1.41–25.97, p=0.02] as well as a sRV ejection fraction below 40% [OR 2.81, 95% CI: 1.18–6.69, p=0.02]. One woman experienced fetal loss, while no neonatal mortality was observed. No significant differences were found between women with CCTGA and TGA. In the subset of women who had an echocardiogram before and after pregnancy, no clear deterioration in sRV was observed. Conclusion The majority of women with a sRV tolerated pregnancy well with a favorable maternal and fetal outcome. Heart failure and arrhythmias were the most common MACE. Funding Acknowledgement Type of funding source: None

Background Current genetic testing guidelines recommend against broad, multi-phenotype genetic testing in survivors of sudden cardiac arrest (SCA) where no cause is identified on clinical screening. Recent reports describe malignant arrhythmic events preceding detectable structural changes in patients with pathogenic variants in cardiomyopathy genes, who go on to demonstrate structural changes in follow up. Purpose We sought to investigate the utility of a broad genetic testing approach, sequencing genes implicated in both arrhythmia syndromes and cardiomyopathy, in SCA survivors where no cause was identified after thorough clinical evaluation. Methods We retrospectively reviewed the clinical and genetic profiles of SCA survivors referred to a specialised genetic heart disease multidisciplinary team in Australia. Multi-phenotype genetic testing included analysis of 174 cardiac genes associated with arrhythmia or cardiomyopathy. Results The cohort was comprised of 86 SCA survivors. A clinical diagnosis was made in 46 (53%) patients while 40 (47%) cases were considered idiopathic, with no cause of arrest identified despite thorough clinical investigation. Thirty-two survivors of idiopathic SCA (80%) underwent broad, multi-phenotype genetic testing through genome (n=1), exome (n=26) or extended panel (n=5) analysis. The majority of the cohort were male (62.5%, n=25) and ≤35 years of age at time of arrest (60%, n=24). Events in this group most commonly occurred at rest or sleep (65.8%, n=25) and 5 patients had a family history of sudden death (12.5%). Seven disease causing variants were identified with a testing yield of 21.9%. There was no difference in demographic or clinical factors between those with and without a disease-causing variant. Six (85.7%) of these clinically actionable variants were identified in genes associated with cardiomyopathy (PKP2, MYBPC3, DES, DSP and ACTN2) that would not have been analysed on a standard commercial cardiac arrhythmia panel. Cardiac magnetic resonance (CMR) imaging was performed prior to genetic testing in 4 of the 6 cases found to have disease-causing variants in cardiomyopathy genes (2 patients did not have CMR performed due to the presence of cardiac devices), with 2 (50%) showing sub-diagnostic changes while 2 (50%) revealed a structurally normal heart. Conclusion A broad approach to genetic testing in idiopathic SCA can improve care for patients and their families by identifying clinically actionable variants that would be missed by phenotype specific gene panels and thus significantly increase the rate of diagnosis. “Concealed cardiomyopathy” represents a clinical challenge in how to manage patients and their relatives who carry a pathogenic cardiomyopathy variant, have no overt signs of structural disease, yet have an important risk of sudden cardiac arrest. Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): Cardiac Society of Australia and New Zealand; National Health and Medical Research Council (Australia)

Background Electrocardiographic (ECG) features on acute phase of Takotsubo syndrome (TTS) is recognized to mimic that of acute anterior myocardial infarction (ant AMI). However, the difference of synthesized 18-leads ECG of both diseases was not elucidated. Purpose To elucidate diagnostic performance of 18-leads ECG to distinguish TTS and acute anterior AMI. Methods We firstly enrolled consecutive 40 patients of TTS, and among 500 ant AMI patients, one to two matching was done by their age and gender. Finally, 40+80 patients (74.5±11.2 years, 87 females) were enrolled, and ECG at onset of both group was estimated. Because of multicollinearity, all significant differences were compared by machine learning (Random Forest method). Results Prevalence of Q wave had no difference. Conversely, ST depression in TTS and ST elevation in ant AMI were significant differences in V7–9 leads. T-wave polarity of V3R-V9 leads were significantly different (flat T-wave in TTS and positive in ant AMI). Machine learning revealed T wave polarity in V7 lead had the highest feature importance. Conclusion 18-leads ECG at onset had powerful diagnostic performance to distinguish the two diseases. Funding Acknowledgement Type of funding source: None

Background The syndrome of inappropriate sinus tachycardia (IST) is well recognized and affects ∼1% of the population. We believe IST in pregnancy is a relatively frequent yet under-recognized phenomenon that may represent a distinct arrhythmia. To date, there are only three case reports in the literature. Purpose To further understand the natural history of IST in pregnancy, and to explore maternal outcomes. Methods A retrospective, observational cohort analysis. Results 19 pregnant women presented to our institute with a definitive diagnosis of IST (as defined by task force criteria) between January 2016 and January 2017. Symptom onset was 4–36 weeks gestation (mean 20 weeks). Of those in their second or subsequent pregnancy (n=8), 50% described symptoms compatible with IST in previous pregnancies. 42% attended the emergency department on ≥1 occasion with symptoms of IST. 32% required hospital admission. 26% required pharmacological therapy (beta-blockers in all). There were no maternal deaths, instances of heart failure or acute coronary syndrome, no thromboembolic or haemorrhagic complications during pregnancy. Rates of Caesarean section were similar to the background rate of our unit; however, rates of induction were notably elevated (58% vs 25%), with 55% of these women being induced purely for symptoms of IST. Following delivery, symptoms resolved within one week for 17 of the women in the cohort, 1 had symptoms resolve after 4 month and 1 had persistent symptoms as she became pregnant again. Conclusion IST in pregnancy likely represents a distinct arrhythmia; the majority of individuals here had symptoms only during pregnancy, which resolved rapidly postpartum. Additionally, half of the women in a second or subsequent pregnancy had suffered IST symptoms during previous pregnancies, with no symptoms in between pregnancies. It is biologically plausible and may represent an exaggerated cardio-autonomic response to the physiological changes of pregnancy such as increased sympathetic tone and change in baroreceptor reflex sensitivity. Recognition of the condition is important given it is associated with significant morbidity, the distressing nature of symptoms leading to high rates of hospitalization and induction of labour. Funding Acknowledgement Type of funding source: None

Background Ablation of premature ventricular contractions (PVCs) is currently based on activation mapping. This strategy is impaired by the absence or paucity of PVCs on the day of the procedure. Frequently, isolated diastolic potentials (DP) are present at the successful ablation site in sinus rhythm (SR), although their meaning is still a matter of debate. Objective Evaluate the feasibility and results of a substrate-based approach for ablation of idiopathic right ventricular outflow tract (RVOT) PVCs, in patients that present with a low PVC burden during the procedure. Methods We included 12 consecutive patients referred for ablation of frequent (>10000/24 hours) idiopathic PVCs from the RVOT that present with less than 2 PVCs/min in the beginning of the procedure. The ablation was based on fast mapping of the RVOT in SR looking for DPs, defined as isolated small amplitude potentials occurring after the T wave of the surface ECG in SR (Figure). The area with DPs was marked and a reduced activation mapping of the PVCs was done in that area. We evaluated the procedure time, mapping, fluoroscopy and radiofrequency (RF) application times. The number of points used for the maps, the area of DPs, local activation time and success rate. Values are presented as median (Q1-Q3). Electroanatomical mapping of the RVOT in SR was also performed in a control group of 10 subjects that underwent ablation of supraventricular arrhythmias, to evaluate the prevalence of DPs in subjects without PVCs. Results The number of PVCs during the procedure was 1 (0.1–1.6)/min. Both groups did not differ in relation to age or gender. Median age 45 (34–65) years, 6 males in the PVC group and 40 (33–65) years, 6 males in the control group, p=0.821 and p=0.231 respectively. The number of points sampled per RVOT map in SR was 400 (193–500) in the PVC group and 330 (277–425) in the control group, p=0.539. All patients in the study group had DPs in the RVOT. None of the control group subjects had DPs in the RVOT. Ablation data is presented in the Table. The acute success rate was 100%. After a median follow-up time of 4 (3–6) months one patient had recurrence. Conclusion In these group of patients with very low PVC burden during the procedure, this approach partially based on substrate mapping, made ablation of the PVCs feasible, in a fast and efficient way. Funding Acknowledgement Type of funding source: None

Introduction Screening for cardiac sarcoidosis (CS) is recommended since it can manifest with ventricular arrhythmias (VA), atrioventricular conduction block (AVB) and sudden cardiac death (SCD). However, risk stratification for SCD is challenging, in particular in patients without overt cardiac symptoms. Purpose This study reports the practice-based risk stratification for SCD and the incidence of arrhythmias and mortality in CS patients by long-term monitoring of arrhythmias. Methods A retrospective, single center cohort study was performed in 537 patients with sarcoidosis screened for cardiac involvement with cardiac MRI and fluorodeoxyglucose PET in an hospital, a Dutch tertiary referral center. CS was diagnosed in 115 of 537 patients (21%), complete follow up was available in 108 patients (94%). After risk assessment for SCD (figure 1) an ICD was implanted in 16 high-risk patients. Within the92 low-risk patients, 80 had an internal loop recorder (ILR) implanted and 12 patients received no device. Chart review was performed to assess the occurrence of VA, AVB, death, ICD therapy and device related complications. Results During a mean follow-up of 31±15 months, 9 out of 80 ILR patients (11.3%) received an ICD of whom 7 (8.8%) based on recorded arrhythmias (VA in 5 and AVB in 2 patients). Five out of the total 25 ICD patients (20%) experienced sustained VA successfully treated with anti-tachycardia pacing in 2 (8%) and terminated spontaneously in all other patients. Two ICD patients experienced a mild pocket infection, treated with antibiotics. Two deaths occurred in the low-risk patients: 1 non-cardiac death and 1 SCD due to asystole. Conclusion The practice-based risk stratification supported an ICD implantation in up to 5% of sarcoidosis patients screened for CS. Sustained VA occurred in 20% of ICD patients.Early detection of important arrhythmias with an ILR can optimize risk assessment for SCD in CS. Practise-based risk stratification Funding Acknowledgement Type of funding source: None

Purpose Cardiac amyloidosis (CA) is a major cause of mortality in patients with amyloidosis because it leads to heart failure and lethal arrhythmia. The present study was aimed to evaluate left ventricular (LV) global myocardial deformation in patients with CA of transmural late gadolinium enhancement (LGE) using tissue tracking MRI. Materials and methods Thirty-nine patients with CA, confirmed by cardiac MRI, and a biopsy of at least one involved organ were enrolled. According to LV ejection fraction (LVEF), they were divided into reduced LVEF (CArEF) and preserved EF (CApEF) groups. Thirty-nine normal controls were recruited (NC). Tissue tracking analysis was done based on cine MRI sequences. LV global longitudinal strain (GLS), global circumferential strain (GCS), and global radial strain (GRS) were computed. Results GLS [CArEF vs. CApEF vs. NC: (−5.82±2.42) % vs. (−8.44±4.15) % vs. (−14.74±2.93)%], GCS [CArEF vs. CApEF vs. NC: (−9.47±2.96) % vs. (−15.01±1.81) % vs. (−19.86±2.30) %], and GRS [CArEF vs. CApEF vs. NC: (11.37±4.68) % vs. (20.61±6.27) % vs. (39.02±8.98) %] were all reduced in the CArEF and CApEF groups compared with healthy control subjects (all P Conclusion MRI-based LV global deformation parameters could be a useful method to assess LV myocardial systolic function and predict LVEF reduction in patients with CA of transmural enhancement on LGE. The differences of GCS and GRS between the CArEF and CApEF groups may also reflect preserved contractile function of the mid- or/and subepicardial myocardium. Figure 1. LV deformation parameters Funding Acknowledgement Type of funding source: None

Background It is important to determine the risk factors that predispose elderly subjects from the general population for symptomatic atrial fibrillation and atrial flutter (AF/AFl), but population-based data for silent AF (SAF) are limited. Aim To study risk factors for symptomatic AF and SAF in a general population screen for subjects age ≥65 where continuous monitoring was performed up to 30 days with a vest-based monitor. Methods The NOMED-AF study was a cross-sectional study based on a representative population sample (n=3014; mean age 77.5±7.9 years; F=1479). In 680 subjects AF/AFl (including 279 with SAF) was diagnosed. Independent risk factors for AF/AFl and SAF were determine on weighted data using multiple logistic regression. Results The independent risk factors for AF/AFl and SAF are summarised in the Table. There are nine independent risk factors for AF/AFl and eight for SAF. Revascularization and obesity were independently associated with patients with (symptomatic) AF/AFl, and CKD was associated with SAF. Other risk factors are common for AF/AFl and SAF. Conclusions AF/AFl and SAF have slightly different associated clinical risk factors in this representative population sample aged ≥65 years. This may facilitated targeted screening programmes for high risk subgroups, particularly for SAF. Funding Acknowledgement Type of funding source: Public Institution(s). Main funding source(s): The research has received funding from the National Centre for Research and Development under grant agreement (STRATEGMED2/269343/18/NCBR/2016)