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ispartof: EUROPACE vol:25 issue:4 ispartof: location:England status: Published online

To provide a detailed description of the workflow at our telecardiology centre and to analyse the workload of real-world remote monitoring with the aim to assess the feasibility to outsource this service.Both analyses indicated similar numbers of events and interventions. Unplanned transmissions were more challenging and required more interventions than planned transmissions. Relatively little time (retrospective median: 1.83 min; prospective median: 1.56 min, per event) was spent on incoming non-actionable 'normal' transmissions (retrospective: 46%; prospective: 40% of all events). Retrospectively 54% and prospectively 60% of transmissions showed abnormalities and were responsible for most of the time expended. Disease-related issues were the most frequent cause for these 'abnormal' alerts. Contacting patients and physicians were key interventions undertaken. Interaction initiated by patients mainly involved the installation process (42%) and bedside monitoring problems (32%).External data centres could deal with 40% of the transmissions, but the decline in workload would be negligible for the in-hospital remote monitoring team, because very little time is spent dealing with the many 'non-event' transmissions whereas most of the time is spent solving clinical problems. Providing sufficient resources and optimising communication protocols is necessary to aid in managing the workload of the remote monitoring team.Implications for practiceContacting patients and physicians are key interventions for specialist nurses in remote monitoring centres.Detailed timing confirmed that most time was spent on relevant disease-related clinical problems.Despite dealing with ∼40% of transmissions, outsourcing to external data centres would decrease the workload only by 15-25%.Patient initiated contacts with questions concerning remote monitoring form a high burden and should be countered by scaling the service and creating communication protocols.

Background In the awakening era of mobile health, wearable devices capable of detecting atrial fibrillation (AF) are on the rise. Smartwatches and wristbands are equipped with photoplethysmography (PPG) technology that enables (semi)continuous rhythm monitoring. These devices have been pioneered already in a few screening trials. However, such devices are being spread among consumers at a pace that is not paralleled by the evidence supporting their clinical performance. This imbalance reflects the urgent need for validation studies. Purpose To determine the diagnostic performance of an artificial intelligence algorithm to detect AF using photoplethysmography acquired by a smartwatch. Methods One hundred patients (≥18 years) without a pacemaker-dependent heart rhythm who were referred to a university hospital or a large tertiary hospital for elective 24-hour ECG Holter monitoring were asked to wear a continuous PPG monitoring smartwatch (i.e. Samsung GWA2 or Empatica E4) simultaneously with the Holter. All activities of daily life were allowed. The ECG trace and PPG waveform were synchronised and fragmented in one-minute fragements. The one-minute ECG fragments were labelled as AF, non-AF, or insufficient quality based on the routine clinical interpretation of the 24-hour Holter (i.e. software + physician overreading). The one-minute PPG fragments were analysed by an artificial intelligence (AI) algorithm (i.e. FibriCheck) and were given the same labels. Diagnostic metrics of the PPG AI algorithm were calculated with respect to the ECG interpretation, for all fragments with sufficient quality for both PPG and ECG. Results Four patients had to be excluded due to technical error (3 Holter errors, 1 smartwatch error). The mean age in the remaining study population (n=96) was 59±16 years, 51 (53%) were men and 15 (15.6%) were known with permanent AF. In this population, simultaneous ECG and PPG monitoring was recorded for 115,245 one-minute fragments. Fragments of insufficient quality for ECG (n=1,454; 1.3%), PPG (n=25,704; 22.3%) or both (n=15,362; 13.3%) were excluded. PPG fragments were more frequently of insufficient quality (p Conclusion Continuous out-of-hospital PPG monitoring using a smartwatch in combination with an AI algorithm can accurately discriminate between AF and non-AF rhythms in a heterogenous patient population. PPG quality is more often affected than ECG quality during daily life activities. Funding Acknowledgement Type of funding sources: Foundation. Main funding source(s): Research Foundation-Flanders, Strategic Basic Research Fund

Background In the awakening era of mobile health, wearables equipped with photoplethysmography (PPG) technology to monitor the heart rate (HR) and rhythm are on the rise. Smartwatches and wristbands enable HR monitoring for consumers at massive scale. Unfortunately, once consumers become patients, physicians are limited by insufficient evidence to support the clinical use of PPG based wearables. Accurate identification of heartbeats is the first step in the interpretation of PPG traces and should be validated. Purpose To assess the agreement between continuous PPG monitoring using a smartwatch and continuous ECG Holter monitoring in the identification of heartbeats and calculation of the HR. Methods One hundred patients (≥18 years) without a pacemaker-dependent heart rhythm who were referred to a university hospital and a large tertiary hospital for elective 24-hour ECG Holter monitoring were asked to wear a continuous PPG monitoring smartwatch (i.e. Samsung GWA2 or Empatica E4) simultaneously with the 24-hour Holter monitor. All activities of daily life were allowed. The ECG trace and PPG waveform were synchronised and fragmented in one-minute fragments. The one-minute ECG fragments were labelled as AF, non-AF, or insufficient quality based on the routine clinical interpretation (i.e. software + physician overreading), and the average HR during each fragment was calculated by Holter algorithm. The PPG fragments were analysed by an artificial intelligence (AI) algorithm (i.e. FibriCheck) that labelled fragments as sufficient or insufficient quality, identified the number of heartbeats and calculated the HR. The agreement between the HR on ECG and PPG in sufficient quality tracings was analysed with linear regression, Pearson's product-moment correlation and Bland-Altman analysis. A subanalysis was performed for AF rhythm and non-AF rhythms. Results A total of 72,725 simultaneous ECG and PPG one-minute fragments were recorded in 96 patients, after excluding 4 patients (due to 3 Holter and 1 smartwatch technical error) and 42,520 minutes (36.9%) of insufficient quality (ECG 1,454 (1.3%); PPG 25,704 (22.3%), ECG and PPG 15,362 (13.3%)). The correlation (r=0.935) between ECG and PPG HR was statistically significant (CI 0.934–0.936; P Conclusion The AI algorithm analysing continuous out-of-hospital PPG tracings can annotate heartbeats and assess HR without a clinically significant bias compared to continuous ECG monitoring, both during AF and non-AF rhythms in a heterogenous patient population. Funding Acknowledgement Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Research Foundation-Flanders, Strategic Basic Research Fund Correlation plot & Bland-Altman plot

Background Cryoballoon ablation (CRYO) for pulmonary vein isolation (PVI) in atrial fibrillation (AF) has become an established treatment option as alternative for radiofrequency catheter ablation (RFCA). As symptom relief is still the main indication for PVI, quality of life (QoL) is a key outcome parameter. This review summarizes the evidence about the evolution of QoL after CRYO. Methods A search for clinical studies reporting QoL outcomes after CRYO was performed on PUBMED and COCHRANE. A total of 506 publications were screened and 10 studies met the in- and exclusion criteria. Results All studies considered QoL as a secondary endpoint and reported significant improvement in QoL between baseline and 12 months follow-up, independent of the QoL instruments used. The effect size of CRYO on QoL was comparable between studies and present in both paroxysmal and persistent AF. Direct comparison between CRYO and RFCA was limited to two studies, there was no difference between ablation modalities after 12 months FU. Two studies in paroxysmal AF reported outcome beyond 12 months follow-up and QoL improvement was maintained up to 36 months after ablation. There were no long-term data available for persistent AF. Conclusion CRYO of AF significantly improves QoL. The scarce amount of data with direct comparison between subgroups limits further exploration. Assessment of QoL should be considered a primary outcome parameter in future trials with long-term follow-up.

ispartof: HeartRhythm Case Rep vol:7 issue:7 pages:492-495 ispartof: location:United States status: Published online

Funding Acknowledgements Type of funding sources: None. Introduction The increasing availability of smartphones has enabled rhythm monitoring in large populations using standalone photoplethysmography (PPG) apps or singe-lead electrocardiography (ECG) with add-on devices. Current guidelines note that when atrial fibrillation (AF) is suspected by an automated algorithm, confirmation on an ECG tracing is required. The use of PPG alone to establish the diagnosis is not generally accepted, even when overread. The performance of physicians to discriminate between sinus rhythm (SR) and AF based on PPG alone is unknown. Purpose To study the performance of physicians to detect AF based on PPG vs single-lead ECG vs 12-lead ECG, and to explore the incremental value of a tachogram, Poincaré plot, and algorithm output to the interpretation of the PPG waveform by physicians. Methods PPG, single-lead ECG and 12-lead ECG data were simultaneously recorded in 30 patients. Diagnostic reference was the 12-lead ECG, read by two cardiologists. Cardiologists, electrophysiologists and cardiology fellows were invited to analyse the data of 30 patients (10 in SR, 10 in SR with extrasystoles and 10 in AF) through online surveys and classify the readings as ‘SR’, ‘ectopic/missed beats’, ‘AF’, ‘flutter’ or ‘unreadable’. For dichotomous analysis, ‘unreadable’ was reclassified as incorrect, the other options were reclassified as AF ‘present’ or ‘absent’. In the first survey, PPG data were presented subsequently as a waveform, stepwise adding the tachogram and Poincaré plot, and algorithm information. In the next two surveys, the single-lead and 12-lead ECG traces were presented. Sensitivity and specificity for all presentations were calculated with respect to the reference diagnosis. Diagnostic performances were compared with the Obuchowski-Rockette’s ANOVA approach with Jackknife covariance estimation and Benjamini-Hochberg correction. Results Sixty-five physicians completed the PPG survey and analysed the PPG waveforms with 88.8% sensitivity and 86.3% specificity for AF. The diagnostic metrics significantly increased to 95.5% sensitivity (P Conclusions PPG rhythm recordings, analysed by physicians as a waveform in combination with the corresponding tachogram and Poincaré plot, achieve similar diagnostic accuracy as single-lead ECG to detect AF. Abstract Figure.

Funding Acknowledgements Type of funding sources: None. Background Population based screening for atrial fibrillation (AF) has been suggested to reduce stroke. Photoplethysmography (PPG) deriving smartphone apps and single-lead electrocardiography (ECG) tools are attractive devices for screening due to their low cost, convenience, and accessibility. Automated algorithm analysis can serve as pre-screening or remote monitoring for AF, while confirmation on an ECG trace >30s is required to establish the diagnosis. This work directly compares the performance of proprietary algorithms on PPG vs single-lead ECG for the detection of AF. Purpose To evaluate and compare the diagnostic performance of a PPG-deriving smartphone app and a single-lead ECG-deriving handheld device for AF detection. Methods Patients were recruited from the cardiology ward. After obtaining written informed consent, demographic and medical information were collected. Patients were instructed to perform one measurement using a pulse-deriving smartphone app and one via a single-lead ECG handheld device. A 12-lead electrocardiogram (ECG) was collected and interpreted by a cardiologist as gold standard. Patients with atrial flutter were excluded, with additional exclusions for insufficient quality measurements and unsuccessful measurements resulting due to technical errors. Unclassified single-lead ECG measurements were handled as test-negative. Sensitivity, specificity and accuracy were calculated with respect to the reference diagnosis. McNemar’s analysis was performed to compare the sensitivity and specificity of the proprietary PPG and single-lead ECG AF detection algorithms. Results The median age in the study population (n = 300) was 70 years (interquartile range: 51-78), 56.3% were men, and the median CHA2DS2-VASc was 3 (interquartile range: 1-4) with an AF-prevalence of 32.3%. PPG signal and single‑lead ECG quality was sufficient in 272/300 (91.0%) and 278/298 (93.3%) participants, respectively. After excluding atrial flutter patients (n = 25) and insufficient quality measurements, the sensitivity and specificity were 97.6% (95% CI 93.8 to 99.3) and 94.1% (95% CI 86.8 to 98.1) for the PPG signal versus 95.7% (95% CI 91.4 to 98.3) and 91.1% (95% CI 83.2 to 96.1) for the single‑lead ECG signal, respectively. Results demonstrated a 96.4% (95% CI 93.2 to 98.3) accuracy for PPG and 94.1% (95% CI 90.4 to 96.6) for single-lead ECG. No significant differences in sensitivity (P = 0.453) or specificity (P = 0.219) between the proprietary PPG and single-lead ECG algorithms were found. Conclusion This study demonstrated equivalent diagnostic performance of PPG and single-lead ECG proprietary AF detection algorithms in smartphone apps.

Funding Acknowledgements Type of funding sources: None. Background Smartphone apps using photoplethysmography (PPG) technology enable digital heart rhythm monitoring through their built-in camera, without the need for additional, specific, or costly hardware. This may positively impact the availability and scalability of remote monitoring. However, the diversity of smartphone specifications on the consumer market may raise concerns regarding the robustness of AF detection algorithms between various devices. Purpose To study the device independency of AF detection performance by a PPG-based smartphone application. Methods Patients from the cardiology department were consecutively enrolled. Patients were handed 7 iOS models and 1 Android model and were asked to consecutively perform one PPG measurement per device. A 12-lead electrocardiogram (ECG) was collected during the same consultation and interpreted by a cardiologist as reference diagnosis. To allow an objective comparison across the devices, patients who failed to perform one successful measurement on each device were excluded. Additional exclusions were atrial flutter rhythms and insufficient quality results. Sensitivity, specificity and accuracy were calculated with respect to the reference diagnosis. McNemar’s analysis was used for the head-to-head comparison of the sensitivity and specificity of the proprietary algorithm on the different smartphone devices. Results A total of 150 patients participated in the study with a median CHA2DS2-VASc score of 3 (interquartile range: 1-5). The median age of the study population was 70 (interquartile range: 56-79) years. In total, 54.7% of the population was male and the AF-prevalence was 35.3%. After the exclusion of patients with atrial flutter (n = 14) and patients who did not successfully perform a PPG measurement on each device (n = 5), diagnostic-grade results of 131 patients were used to calculate the performance of the proprietary algorithm. The sensitivity and specificity of the AF detection algorithm ranged from 90.9% (95% CI 75.7-98.1) to 100.0% (95% CI 91.0-100) and 94.5% (95% CI 86.6-98.5) to 100.0% (95% CI 94.6-100), respectively. The overall accuracy across the devices ranged from 94.4% (95% CI 88.3-97.9) to 99.0% (95% CI 94.6-100). Head-to-head comparisons of the results did not reveal significant differences in sensitivity (P = 0.125-1.000) or specificity (P = 0.375-1.000) of the proprietary AF detection algorithm among the different devices. Conclusion This study demonstrated the device-independent nature of the PPG-deriving smartphone application with respect to 12-lead ECG diagnosis.

BACKGROUND Atrial fibrillation (AF) is the most common arrhythmia after cardiac surgery, yet the precise incidence and significance of arrhythmias after discharge home need to be better defined. Photoplethysmography (PPG)-based smartphone apps are promising tools to enable early detection and follow-up of arrhythmias. OBJECTIVE By using a PPG-based smartphone app, we aimed to gain more insight into the prevalence of AF and other rhythm-related complications upon discharge home after cardiac surgery and evaluate the implementation of this app into routine clinical care. METHODS In this prospective, single-center trial, patients recovering from cardiac surgery were asked to register their heart rhythm 3 times daily using a Food and Drug Administration–approved PPG-based app, for either 30 or 60 days after discharge home. Patients with permanent AF or a permanent pacemaker were excluded. RESULTS We included 24 patients (mean age 60.2 years, SD 12 years; 15/23, 65% male) who underwent coronary artery bypass grafting and/or valve surgery. During hospitalization, 39% (9/23) experienced postoperative AF. After discharge, the PPG app reported AF or atrial flutter in 5 patients. While the app notified flutter in 1 patient, this was a false positive, as electrocardiogram revealed a 2nd-degree, 2:1 atrioventricular block necessitating a permanent pacemaker. AF was confirmed in 4 patients (4/23, 17%) and interestingly, was associated with an underlying postoperative complication in 2 participants (pneumonia n=1, pericardial tamponade n=1). A significant increase in the proportion of measurements indicating sinus rhythm was observed when comparing the first to the second month of follow-up (PP=.002). The majority of participants (17/23, 74%), as well as the surveyed primary care physicians, experienced positive value by using the app as they felt more involved in the postoperative rehabilitation. CONCLUSIONS Implementation of smartphone-based PPG technology enables detection of AF and other rhythm-related complications after cardiac surgery. An association between AF detection and an underlying complication was found in 2 patients. Therefore, smartphone-based PPG technology may supplement rehabilitation after cardiac surgery by acting as a sentinel for underlying complications, rhythm-related or otherwise.

Background Atrial fibrillation (AF) is the most common arrhythmia after cardiac surgery, yet the precise incidence and significance of arrhythmias after discharge home need to be better defined. Photoplethysmography (PPG)-based smartphone apps are promising tools to enable early detection and follow-up of arrhythmias. Objective By using a PPG-based smartphone app, we aimed to gain more insight into the prevalence of AF and other rhythm-related complications upon discharge home after cardiac surgery and evaluate the implementation of this app into routine clinical care. Methods In this prospective, single-center trial, patients recovering from cardiac surgery were asked to register their heart rhythm 3 times daily using a Food and Drug Administration–approved PPG-based app, for either 30 or 60 days after discharge home. Patients with permanent AF or a permanent pacemaker were excluded. Results We included 24 patients (mean age 60.2 years, SD 12 years; 15/23, 65% male) who underwent coronary artery bypass grafting and/or valve surgery. During hospitalization, 39% (9/23) experienced postoperative AF. After discharge, the PPG app reported AF or atrial flutter in 5 patients. While the app notified flutter in 1 patient, this was a false positive, as electrocardiogram revealed a 2nd-degree, 2:1 atrioventricular block necessitating a permanent pacemaker. AF was confirmed in 4 patients (4/23, 17%) and interestingly, was associated with an underlying postoperative complication in 2 participants (pneumonia n=1, pericardial tamponade n=1). A significant increase in the proportion of measurements indicating sinus rhythm was observed when comparing the first to the second month of follow-up (P Conclusions Implementation of smartphone-based PPG technology enables detection of AF and other rhythm-related complications after cardiac surgery. An association between AF detection and an underlying complication was found in 2 patients. Therefore, smartphone-based PPG technology may supplement rehabilitation after cardiac surgery by acting as a sentinel for underlying complications, rhythm-related or otherwise.

Background: With increasing cardiovascular implantable electronic device (CIED) implantations, growing number of extractions of leads and devices are noted, mainly for complications such as infection and lead dysfunction. The optimal timing for re-implantation remains uncertain. We investigated the time to eventual re-implantation of CIEDs in the University Hospitals Leuven, Belgium.Methods: All consecutive patients, referred for extraction between January 2005 and December 2016, were analysed for the timing of eventual re-implantation.Results: Two-hundred and forty-three patients were included. Mean follow-up was 77 ± 37 months. Global re-implantation rate was 89.3%: 100% for lead dysfunctions versus 80.7% following infections. Median time to re-implantation (TTR) was 0 [0-111] days and 8.5 [0-3025] days, respectively (p

Background Atrioventricular nodal reentrant tachycardia (AVNRT) is a common supraventricular arrhythmia that is frequently encountered in an otherwise healthy patient population. Recent guidelines of the European Society of Cardiology underline the role of catheter ablation in the long-term management of these patients. Case summary This case describes the clinical presentation and treatment options in a patient with typical slow/fast AVNRT, the most common subform of AVNRT, where antegrade conduction occurs over the slow pathway and retrograde conduction over the fast pathway. The ablation strategy in these patients is illustrated based on intracardiac recordings in combination with per-procedural three-dimensional imaging. Discussion Atrioventricular nodal reentrant tachycardia is a common arrhythmia with good prognosis but significant impact on quality of life of affected patients. Catheter ablation should be considered early as it can be performed safely and with a very high success rate.

BACKGROUND: Transvenous 3 permanent pacemaker-related infection is a severe condition associated with significant morbidity and mortality. Leadless pacemakers may be more resistant to bacterial seeding during bloodstream infection because of its small surface area and encapsulation in the right ventricle. This study reports the incidence and outcomes of bacteraemia in patients implanted with a Micra leadless pacemaker. We present 18 F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) findings obtained in a subgroup of patients. METHODS: We report a retrospective cohort study of 155 patients who underwent a Micra TPS implant procedure at the University Hospitals of Leuven between July 2015 and July 2019. We identified the patients who developed an episode of bacteraemia, proved by ≥2 positive blood cultures. RESULTS: Of the 155 patients, 15 patients presented an episode of bacteraemia at a median of 226 days (range: 3-1129) days after the implant procedure. Gram-positive species accounted for 73.3% (n = 11) of the bacteraemia including Staphylococcus (n = 5), Enterococcus (n = 3), and Streptococcus (n = 3). The source of infection was identified in nine patients (60%) including endocarditis in four patients, urinary tract in three patients, and skin in two patients. 18 F-FDG PET/CT imaging performed in six patients did not show sign of infection around the leadless pacemaker. Bacteraemia was resolved in all patients after adequate antibiotherapy. Four patients died early during follow up. For all other patients, there were no recurrence of systemic infection during a median follow up of 263 days (range: 15-1134). CONCLUSION: In our small cohort, no leadless pacemaker endocarditis was observed among patients with bacteraemia. ispartof: JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY vol:31 issue:9 pages:2440-2447 ispartof: location:United States status: published

BACKGROUND: Permanent pacing is common after valve intervention. The presence of a conventional pacemaker in this population is recognized as a risk factor for infectious events. Therefore, a leadless pacing system could be the preferred strategy when permanent pacing is required after valve intervention. AIM: To report periprocedural outcomes and follow-up of patients undergoing implantation of a leadless pacing system after valve intervention. METHODS: Patients with previous valve intervention at the time of attempted implantation of a leadless pacemaker (Micra™, Medtronic, Minneapolis, MN, USA) were included, and were compared with a control group (patients also implanted with Micra™ without valve intervention). RESULTS: Among a total of 170 Micra™ implantation procedures, 54 patients (31.8%) had a history of valve intervention: 28 after aortic valve replacement; 10 after mitral valve replacement; one after single tricuspid valvuloplasty; and 15 after multiple valve surgery. Median age of the patients was 82.5 (77.0-86.0) years and 53.7% were male. Patients with previous valve intervention had a higher incidence of arterial hypertension (P=0.014) and ischaemic heart disease (P=0.040). The primary indications for permanent pacing after valve intervention were high-degree atrioventricular block (59.3%) and atrial fibrillation with bradycardia (27.8%). Micra™ was successfully implanted in all patients (n=170) without any procedure-related major complications. During a median follow-up of 12 months, electrical performance was excellent and similar in both groups. Also, a similar reduction in left ventricular ejection fraction was observed at 12 months in both groups, which was correlated with the percentage of right ventricular pacing. CONCLUSION: A leadless pacemaker is safe and efficient after valve intervention, and therefore represents an effective pacing option in patients after valve intervention. ispartof: ARCHIVES OF CARDIOVASCULAR DISEASES vol:113 issue:12 pages:772-779 ispartof: location:Netherlands status: published

BACKGROUND: The Micra Transcatheter Pacing System is implanted directly in the right ventricle (RV) through the femoral vein using a steerable transcatheter delivery system. The present study was done to identify determinants of difficult leadless pacemaker implant procedures including operator, patient, and RV anatomical characteristics. METHODS: All patients who underwent a Micra implant from July 2015 to December 2018 at our center were analyzed. From an RV angiogram acquired during implantation, RV geometry including systolic and diastolic volumes and ejection fraction was characterized. The presence of septomarginal trabeculation was noted. RESULTS: One hundred twenty-six patients (mean age: 79 ± 11 years old, mostly male: 77%) were enrolled. Mean Micra RV implant procedure time was 24 ± 23 min, with 1.7 ± 1.3 deployments of the device. No significant change in implant procedure time was observed after the first 30 implants. Eleven patients had a prominent septal component of the septomarginal trabeculation in the RV. Univariate analysis showed that the procedure time was positively correlated with the presence of a prominent septal component of the septomarginal trabeculation (P

BACKGROUND: With its steerable transcatheter delivery system, the Micra can be deployed in nonapical positions within the right ventricle, potentially allowing reduction of the paced QRS width. We sought to evaluate the safety and long-term performance of the right ventricular outflow tract (RVOT) pacing using the Micra transcatheter pacing system (TPS). We also compared the paced QRS between RVOT, mid-septal, and apical implant positions. METHODS: All patients who underwent a Micra TPS implantation at the University Hospitals of Leuven were enrolled in this observational study. Right ventricular (RV) position of the device was assessed on per-procedural ventriculography. Paced QRS was analyzed and follow-up completed at 1 month and then every 6 months. RESULTS: Among the 133 patients included (mean follow-up: 13 ± 11 months), 45 were implanted in the RVOT, 58 midseptally, and 30 at the apex. All implant procedures were successful and no pericardial effusion was encountered within the 30 days post-implant. Two major complications were reported with devices implanted at the apex. Pacing impedance was significantly higher in the RVOT compared to the mid-septal and apical position (P

The onset of cardiac arrhythmias depends on electrophysiological and structural properties of cardiac tissue. One of the most important changes leading to arrhythmias is characterised by the presence of a large number of non-excitable cells in the heart, of which the most well-known example is fibrosis. Recently, adipose tissue was put forward as another similar factor contributing to cardiac arrhythmias. Adipocytes infiltrate into cardiac tissue and produce in-excitable obstacles that interfere with myocardial conduction. However, adipose infiltrates have a different spatial texture than fibrosis. Over the course of time, adipose tissue also remodels into fibrotic tissue. In this paper we investigate the arrhythmogenic mechanisms resulting from the presence of adipose tissue in the heart using computer modelling. We use the TP06 model for human ventricular cells and study how the size and percentage of adipose infiltrates affects basic properties of wave propagation and the onset of arrhythmias under high frequency pacing in a 2D model for cardiac tissue. We show that although presence of adipose infiltrates can result in the onset of cardiac arrhythmias, its impact is less than that of fibrosis. We quantify this process and discuss how the remodelling of adipose infiltrates affects arrhythmia onset. ispartof: Scientific Reports vol:8 issue:1 pages:2050- ispartof: location:England status: published

Fibroblast (Fb) differentiation and interstitial fibrosis contribute to cardiac remodeling and loss of function after myocardial infarction (MI). We investigated regional presence and regulation of fibrosis in a pig MI model. In vivo analysis of regional function and perfusion defined three regions: the scar, the myocardium adjacent to the scar (MIadjacent, reduced function, reduced perfusion reserve), and the remote myocardium (MIremote, minimal functional deficit, maintained perfusion). Interstitial and perivascular fibrosis, and increase of collagen type I, was only observed in the MIadjacent. Fb activated protein-alpha (FAP-α) was enriched in MIadjacent compared to MIremote. TGF-β1, which triggers Fb differentiation, was upregulated in both MIadjacent and MIremote, whereas lysyl oxidase, a regulator of collagen cross-linking, and the proteoglycans decorin and biglycan were only increased in the MIadjacent. Fb isolated and cultured for 4 days had myoFb characteristics with little difference between MIremote and MIadjacent, although RNA sequencing revealed differences in gene expression profiles. Fbs from all regions maintained proliferative capacity, and induced contraction of 3-D collagen matrices but scar myoFb was more effective. These data suggest that after MI, signaling through TGF-β1, possibly related to increased mechanical load, drives Fb activation throughout the left ventricle while regional signaling determines further maturation and extracellular matrix remodeling after MI.

Atrial fibrillation (AF) is the most frequent sustained cardiac arrhythmia. AF is shown to be a progressive disease, which is strongly associated with important structural (morphological and histological), electrical and mechanical remodeling of the left atrium (LA). Adipose tissue accumulation has been shown to be a risk factor in AF. We set out to explore the connection between adipose tissue coverage of the LA surface, for both the complete LA and specific regions and the progression of AF. In this study we propose a methodology to study the regional coverage of the left-atrial wall with adipose tissue based on magnetic resonance data. Validation was performed in a sheep model. While the total amount of left-atrial adipose tissue was higher in the sheep with AF, no changes in regional coverage were observed.

An 82-year-old female patient with a history of aortic valve replacement and mitral valve repair was admitted several times with severe heart failure due to severe mitral valve regurgitation ([Figure 1A][1]). Given the poor prognosis and the high operative risk of redo surgery (European System for

Carcinoid heart disease (CHD) is a rare form of valvular heart disease characterized by right-sided heart valve dysfunction. Carcinoid heart disease occurs most frequently when carcinoid tumour cells metastasize from a primary site in the gut to the liver, so that vasoactive substances produced by the tumour are able to reach the systemic circulation. By contrast, in ovarian carcinoid tumours carcinoid heart disease develops in the absence of liver metastasis, because vasoactive substances can be released directly into the systemic circulation, bypassing the first-pass metabolism of the liver. There are only a few case reports in the world literature of carcinoid heart disease caused by ovarian carcinoid tumour. We report a case of an 85-year-old woman with carcinoid heart disease caused by a bilateral ovarian carcinoid tumour metastasized from a primary ileal site.

Accumulation of atrial adipose tissue is associated with atrial fibrillation (AF). However, the underlying mechanisms remain poorly understood. We examined the relationship between the characteristics of fatty infiltrates of the atrial myocardium and the history of AF.Atrial samples, collected in 92 patients during cardiac surgery and in a sheep model of persistent AF, were subjected to a detailed histological analysis. In sections of human right atrial samples, subepicardial fatty infiltrations were commonly observed in the majority of patients. A clear difference in the appearance and fibrotic content of these fatty infiltrations was observed. Fibro-fatty infiltrates predominated in patients with permanent AF (no AF: 37 ± 24% vs. paroxysmal AF: 50 ± 21% vs. permanent AF: 64 ± 23%, P0.001). An inverse correlation between fibrotic remodelling and the amount of subepicardial adipose tissue suggested the progressive fibrosis of fatty infiltrates with permanent AF. This hypothesis was tested in a sheep model of AF. In AF sheep, an increased accumulation of peri-atrial fat depot was observed on cardiac magnetic resonance imaging and dense fibro-fatty infiltrations predominated in the left atria of AF sheep. Cellular inflammation, mainly consisting of functional cytotoxic T lymphocytes, was observed together with adipocyte cell death in human atria.Atrial fibrillation is associated with the fibrosis of subepicardial fatty infiltrates, a process in which cytotoxic lymphocytes might be involved. This remodelling of the atrial subepicardium could contribute to structural remodelling forming a substrate for AF.

An acute increase in blood pressure is associated with the occurrence of premature ventricular complexes (PVCs).We aimed to study the timing of these PVCs with respect to afterload-induced changes in myocardial deformation in a controlled, preclinically relevant, novel closed-chest pig model.An acute left ventricular (LV) afterload challenge was induced by partial balloon inflation in the descending aorta, lasting 5-10 heartbeats (8 pigs; 396 inflations).Balloon inflation enhanced the reflected wave (augmentation index 30% ± 8% vs 59% ± 6%; P.001), increasing systolic central blood pressure by 35% ± 4%. This challenge resulted in a more abrupt LV pressure decline, which was delayed beyond ventricular repolarization (rate of pressure decline 0.16 ± 0.01 mm Hg/s vs 0.27 ± 0.04 mm Hg/ms; P.001 and interval T-wave to peak pressure 1 ± 12 ms vs 36 ± 9 ms; P = .008), during which the velocity of myocardial shortening at the basal septum increased abruptly (ie, postsystolic shortening) (peak strain rate -0.6 ± 0.5 s(-1) vs -2.5 ± 0.8 s(-1); P.001). It is exactly at this time of LV pressure decline, with increased postsystolic shortening, and not at peak pressure, that PVCs occur (22% of inflations). These PVCs preferentially occurred at the basal and apical segments. In the same regions, monophasic action potentials demonstrated the appearance of delayed afterdepolarization-like transient depolarizations as origin of PVCs.An acute blood pressure increase results in a more abrupt LV pressure decline, which is delayed after ventricular repolarization. This has a profound effect on myocardial mechanics with enhanced postsystolic shortening. Coincidence with induced transient depolarizations and PVCs provides support for the mechanoelectrical origin of pressure-induced premature beats.

Epicardial adipose tissue (EAT) is recognized as potentially involved in the pathophysiology of atrial fibrillation (AF). In addition to EAT fatty infiltration commonly observed in myocardium might be also associated with the substrate for AF. We conducted a histological study in 93 human right atrial samples obtained during cardiac surgery and in a sheep model of long-term persistent AF (PAF) induced by atrial tachypacing (24±8 weeks) (15 PAF, 11 SR). Upon Sirius Red and Harris Haematoxylin staining, human atria showed various degree of fatty infiltration starting from the epicardium (rarely from vessels), which could be associated with various degree of subepicardial fibrosis realizing in some cases a true fibro-fatty infiltration. The extent of remodeled epicardium was assessed as % of infiltrating and fibrotic epicardium±adipose tissue to total epicardial length; 44±26 % of the epicardium was remodeled. A multiple regression model (including history of AF, % adipose tissue, age, BodyMassIndex, coronary artery bypass, ejection fraction) significantly predicted the percentage of epicardial remodeling (R=0.501, p=0.003). Only AF and the % adipose tissue were significant predictors (respectively β=0.27;p=0.016 and β=-0.267;p=0.016). To further analyze the relationship between fibro-fatty infiltration and AF, a histological study was performed in LA specimen of a sheep PAF model which revealed 4 grades of subepicardial infiltrates from pure fatty to dense fibro-fatty infiltration (fig A). EAT infiltrates (316) were graded, demonstrating a shift towards more severe grades in the AF group p Conclusion: , AF is associated with the transformation of fat into fibro-fatty infiltrations suggesting that the subepicardial adipose tissue plays a role in the atrial fibrotic remodeling.

Cardiologia CROATICA Objectives: We have recently shown that an acute afterload increase of the left ventricle induces premature ventricular beats (PVB). We explored mechanical dispersion, which has recently been linked to a greater incidence of arrhythmias in post infarction ICD patients, as a potential underlying mechanism. Methods: 7 closed chest, closed pericardium pigs were instrumented with an aortic balloon in the mid-thoracic descending aorta. Parasternal long-axis B-mode images were acquired before and during the balloon inflation (N=22), causing a 30% increase in systolic blood pressure and an acute LV dilatation over 5-10 beats. Before and during inflation, segmental septal deformation was analyzed using speckle tracking and timing and the amount of peak strain were measured. Mechanical dispersion was calculated as the standard deviation (SD) of the time to peak strain in the three segments. 12 lead ECG was acquired in all animals. Results: PVBs occurred in 33% of the pressure challenges. The afterload increase caused a visible dispersion in the timing of the strain curves of the three segments (Figure 1a). Despite no change in QT interval, mean time of peak strain increased from 291±81 ms, in preinflation to 352±56 ms during inflation in the three segments, resulting in postsystolic shortening. The SD increased significantly from preinflation to inflation (p=0.02) (Figure 1b). While strain at aortic valve closure clearly went down with afterload (-14.74±6 to -11.04±4.02, p=0.0001), peak shortening remained similar (-15.79±6.09 to -15.12±4.56, p=0.479). Conclusion: Acute afterload increase of the LV significantly increased the difference in time to peak strain between the three septal segments, resulting in increased mechanical dispersion, which may play a role in pressure-induced arrhythmias.

Purpose: Most interventional studies providing insight to left ventricular (LV) mechanics during afterload increase have been performed on open chest/pericardium animals. However, little is known about the impact of acute afterload on LV wall contraction timing in the setting of a more physiological, closed chest, closed pericardium model. Thus, we aimed to study the impact of acute LV pressure overload on the timing of regional myocardial contraction in such a model. Methods: 7 anesthetised, closed chest/closed pericardium pigs were instrumented with a balloon positioned in the descending aorta, partially inflated during 5-10 heartbeats creating an approx. 30% LV pressure increase. Echocardiographic LV LAX B-mode cine-loops were acquired in cine-loops including 5 preinflation and 5-10 inflation beats. Anatomic M-mode images of the LV base and apex were created and the time from Q wave on the simultaneous ECG trace to end- systolic (ES) septal and posterior wall thickening was measured. Results: At baseline, septal ES thickening occurred sooner at the apex (309.7±47.8 ms) than at the LV base (362.6±47.4 ms, p

Background and aims Accumulation of atrial adipose tissue is associated with atrial fibrillation (AF). However the underlying mechanisms remain poorly understood. We examined the relationship between fatty infiltrations in the atrial myocardium and the development of AF structural/fibrotic substrate. Methods Atrial samples, collected in 92 patients during cardiac surgery and in a sheep model of persistent AF, were subjected to a detailed histological analysis. A transition from fatty to fibro-fatty infiltrates with persistence of AF was tested in the AF sheep model using a cardiac magnetic resonance imaging. Results In sections of human right atrial samples, subepicardial fatty infiltrations were commonly observed in the majority of patients. A clear difference in the appearance and fibrotic content of these fatty infiltrations was observed. Fibro-fatty infiltrates predominated in patients with permanent AF (no AF 37±24% vs paroxysmal AF 50±21% vs permanent AF 64±23%, P

Atrial fibrillation (AF) is the most common cardiac arrhythmia and imposes a huge clinical and economic burden. AF is correlated with an increased morbidity and mortality, mainly due to stroke and heart failure. Cardiovascular imaging modalities, including echocardiography, computed tomography (CT), and cardiovascular magnetic resonance (CMR), play a central role in the workup and treatment of AF. One of the major advantages of CMR is the high contrast to noise ratio combined with good spatial and temporal resolution, without any radiation burden. This allows a detailed assessment of the structure and function of the left atrium (LA). Of particular interest is the ability to visualize the extent of LA wall injury. We provide a focused review of the value of CMR in identifying the underlying pathophysiological mechanisms of AF, its role in stroke prevention and in the guidance of radiofrequency catheter ablation. CMR is a promising technique that could add valuable information for therapeutic decision making in specific subpopulations with AF.

Aim: As acute short-lived increase in afterload may be a contributory mechanism to sudden death, we studied an acute 30% systolic pressure increase (SBPI) in a closed chest, closed pericardium porcine model, closed pericardium being essential to the model clinical applicability. Methods: 7 pigs were studied. All had an acute 5 beat 30% SBPI induced by a non-occlusive mid- descending aortic balloon inflation and release. Each challenge was continuously monitored for changes in cardiac morphology and function by cardiac ultrasound (2D, Doppler and Doppler Myocardial Imaging) and changes were correlated with pressure data from 3 Millar catheters (LV/Ao ; LA ; RV/RA). Continuous 12 lead ECG and intracardiac electrograms were also recorded. Results: Balloon inflation caused an acute diastolic pressure increase in all cavities (except pulmonary artery) with early diastolic preceding late changes and a corresponding systolic increase in LV, LA and RA pressures. Acute LV dilatation resulted in pericardial flattening (which is a visualization of the effects of pericardial constraint), a septal shift towards the RV and a decrease in RV size with a 30% reduction in LVEF % (Fig1a). During inflation, pericardial excursion flattened > 40% in basal, mid and apical LV segments, mostly mid wall (from 3.4±1.4 mm to 1.6±0.7 mm, p

Cardiologia CROATICA Background: The speed and timing of changes in diastolic function parameters during acute LV loading and unloading is unknown. Methods: In a closed chest, closed pericardium porcine model, LV systolic pressure was increased by 30% using a transient descending aortic partial balloon inflation. Morphology and mechanical changes were monitored in real time by echocardiography, as were changes in left and right heart diastolic pressures by 3 Millar catheters. Simultaneous blood pool and tissue Doppler data (radial and long axis) were acquired during afterload changes. Results: In 7 animals, acute loading consistently induced LV dilatation and a rightwards ventricular septal shift due to lateral LV pericardial restraint. This reduced RV volume. Afterload increase caused an immediate decrease in early diastolic filling wave (E) and lateral wall velocity (E’). This was mirrored by an immediate increase in both early diastolic LV (LVDPmin) and LA (LADPmin) pressure (Figure 1). Pulmonary vein flow gradually reduced with decreased late flow. The rightwards septal shift induced a small but significant increase in RVDPmin and an increase in mean RA pressure, but failed to increase pulmonary artery pressure. Acute afterload release immediately returned E values to baseline, but E’ showed a transient further 3 to 5 beat increase before it normalized. Conclusion: Acute afterloading variably elevates all cardiac diastolic pressures and reduces LV relaxation. These early changes in myocardial mechanics occur simultaneously with changes in LVDPmin. Right heart diastolic pressures increase due to the septal shift which both reduced RV volume and decreased LV compliance but did not elevate pulmonary pressure. E’/E recovery differed which could be attributed to transient preload changes.