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Background: Atrial arrhythmias (AA) and heart failure (HF) are major causes of hospitalisation in adult congenital heart disease (ACHD). This study aimed to evaluate the temporal relationship between AA and HF onset, the association between HF and the success of radiofrequency ablation (RFA), and how HF influences outcomes in patients with AA., Methods: In this single-centre retrospective cohort study, data from 3995 patients with ACHD were analysed. Dates of first AA and HF presentations were documented, and outcomes of RFA, including acute and long-term success, were assessed. All-cause mortality was compared between patients with AA and those with both AA and HF., Results: The median age at last follow-up was 33 years (IQR 26-42). AA was observed in 348 patients (8.7%), and HF in 256 (6.4%). Among patients who developed both AA and HF (n=130), AA preceded HF in 79% of cases, with a median interval of 6 years (IQR 2-13) before HF diagnosis. In the remaining cases, AA occurred after HF diagnosis (median 2 years, IQR 1-6). RFA was performed in 119 patients (34.2%), 45 of whom had HF. Two years after RFA, 72% of patients were free from AA recurrence. Patients without HF had higher acute success rates (98% vs 90%) and lower recurrence rates (48% vs 76%) than those with HF. Patients with AA with HF had worse overall survival compared with those without HF., Conclusions: In patients with ACHD, AA frequently precedes HF by several years. RFA can be an effective treatment for AA, but acute success is lower and recurrence rate higher when HF is present., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2025. No commercial re-use. See rights and permissions. Published by BMJ Group.)

Aims: Atrial fibrillation (AF) and atrial flutter (AFL) after cardiac surgery are common and associated with adverse outcomes. The increased risk related to AF or AFL may extend beyond discharge. This study aims to determine whether photoplethysmography (PPG)-based smartphone monitoring to detect AF or AFL after hospital discharge following cardiac surgery improves AF management., Methods and Results: The intervention group performed 1 min rhythm checks three times daily using a smartphone-based PPG application during 6 weeks after hospitalization for cardiac surgery. The primary outcome involved AF management interventions by independent physicians, including initiation of oral anticoagulation (OAC), direct cardioversion, and up-titration or initiation of antiarrhythmic drugs. The study included 450 patients [mean (SD) age, 64.1 (9.2) years; 96 women (21.3%); 130 patients with AF history (28.9%); median (IQR) CHA2DS2-VASc score, 2 (1-3)], of whom 238 were randomized to PPG-based monitoring and 212 to usual care. AF/AFL was detected with PPG or electrocardiography in 44 patients (18.5%) in the monitoring group and 4 patients (1.9%) in the usual care group (OR 11.8; 95% CI, 4.2-33.3; P < 0.001); these were new detections in, respectively, 22 patients (9.2%) and 1 patient (0.5%) (OR 21.3; 95% CI, 2.9-166.7; P = 0.003). AF management interventions occurred in 24 patients (10.1%) in the monitoring group compared to 5 patients (2.4%) in the usual care group [odds ratio (OR), 5.1; 95% CI, 1.8-14.4; P = 0.002]., Conclusion: In unselected patients discharged home following cardiac surgery, PPG-based smartphone monitoring revealed significantly more AF/AFL which led to significantly more optimization of AF management., Competing Interests: Conflict of interest: H.H. received personal lecture and consultancy fees from Bayer, Biotronik, Bristol Myers Squibb, Centrix Healthcare Ltd, Daiichi Sankyo, Downtown Europe, Pfizer-BMS, ESC, Medscape, Springer Healthcare Ltd, and Viatris Pharmaceuticals Inc. He received unconditional research grants through the University of Antwerp and/or the University of Hasselt from Abbott, Bayer, Biosense Webster, Boston Scientific, Daiichi Sankyo, FibriCheck/Qompium, Medtronic, and Pfizer-BMS, all outside the scope of this work. P.V. holds stock in Qompium NV. The other authors have nothing to declare., (© The Author(s) 2025. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Background: Consumer-oriented wearable devices (CWDs) such as smartphones and smartwatches have gained prominence for their ability to detect atrial fibrillation (AF) through proprietary algorithms using electrocardiography or photoplethysmography (PPG)-based digital recordings. Despite numerous individual validation studies, a direct comparison of interdevice performance is lacking., Objective: This study aimed to evaluate and compare the ability of CWDs to distinguish between sinus rhythm and AF., Methods: Patients exhibiting sinus rhythm or AF were enrolled through a cardiology outpatient clinic. The participants were instructed to perform heart rhythm measurements using a handheld 6-lead electrocardiogram (ECG) device (KardiaMobile 6L), a smartwatch-derived single-lead ECG (Apple Watch), and two PPG-based smartphone apps (FibriCheck and Preventicus) in a random sequence, with simultaneous 12-lead reference ECG as the gold standard., Results: A total of 122 participants were included in the study: median age 69 (IQR 61-77) years, 63.9% (n=78) men, 25% (n=30) with AF, 9.8% (n=12) without prior smartphone experience, and 73% (n=89) without experience in using a smartwatch. The sensitivity to detect AF was 100% for all devices. The specificity to detect sinus rhythm was 96.4% (95% CI 89.5%-98.8%) for KardiaMobile 6L, 97.8% (95% CI 91.6%-99.5%) for Apple Watch, 98.9% (95% CI 92.5%-99.8%) for FibriCheck, and 97.8% (95% CI 91.5%-99.4%) for Preventicus (P=.50). Insufficient quality measurements were observed in 10.7% (95% CI 6.3%-17.5%) of cases for both KardiaMobile 6L and Apple Watch, 7.4% (95% CI 3.9%-13.6%) for FibriCheck, and 14.8% (95% CI 9.5%-22.2%) for Preventicus (P=.21). Participants preferred Apple Watch over the other devices to monitor their heart rhythm., Conclusions: In this study population, the discrimination between sinus rhythm and AF using CWDs based on ECG or PPG was highly accurate, with no significant variations in performance across the examined devices., (©Femke Wouters, Henri Gruwez, Christophe Smeets, Anessa Pijalovic, Wouter Wilms, Julie Vranken, Zoë Pieters, Hugo Van Herendael, Dieter Nuyens, Maximo Rivero-Ayerza, Pieter Vandervoort, Peter Haemers, Laurent Pison. Originally published in JMIR Formative Research (https://formative.jmir.org).)

Aims: Trials on integrated care for atrial fibrillation (AF) showed mixed results in different AF populations using various approaches. The multicentre, randomized AF-EduCare trial evaluated the effect of targeted patient education on unplanned cardiovascular outcomes., Methods and Results: Patients willing to participate were randomly assigned to in-person education, online education, or standard care (SC) and followed for minimum 18 months. Education focused on four aspects of integrated AF care: (i) knowledge on AF and oral anticoagulation; (ii) reinforcement of medication adherence; (iii) awareness about risk factors; and (iv) reachability for AF-related questions. The primary endpoint was the composite of cumulative events of unplanned cardiovascular hospitalizations and consultations, emergency department visits for cardiovascular reasons, and cardiovascular death. A total of 1038 patients (69.8 ± 9.2 years) were followed up for 26.9 ± 9.4 months. Education (both in-person and online) significantly improved AF-related knowledge compared to SC (P < 0.001), increased patient awareness about risk factors, led to high medication adherence, and encouraged patients to ask health-related questions. However, in-person education did not show an effect on the primary outcome compared to SC [HR 1.02 (0.91-1.14); P = 0.80] that was also not the case when comparing online education vs. SC [HR 1.18 (0.95-1.46), P = 0.65]. Exploratory subgroup analyses showed a heterogeneous effect over the centres, but a positive impact of in-person education in patients with asymptomatic AF, being 70 years old or younger, and without a history of heart failure., Conclusion: AF-EduCare showed that intensive targeted patient education did not lead to less unplanned cardiovascular events in the AF patient population as a whole, although subgroups might benefit., Competing Interests: Conflict of interest: H.H. received personal lecture and consultancy fees from Bayer, Biotronik, Bristol-Myers Squibb, Centrix Healthcare Ltd, Daiichi-Sankyo, Downtown Europe, Pfizer-BMS, European Society of Cardiology, Medscape, Springer Healthcare Ltd, and Viatris Pharmaceuticals Inc. M.D. received support to attend medical meetings from Pfizer and Biosense Webster. J.E. received lecture fees and unconditional research support from Bayer and Biotronik. None of the other authors did receive any personal honoraria. H.H. and L.D. received unconditional research support through the University of Hasselt or University of Antwerp from Abbott, Bayer, Biosense Webster, Boston-Scientific, Daicchi-Sankyo, Fibricheck/Qompium, Medtronic, and Pfizer-BMS, none related to this work. All remaining authors have declared no conflicts of interest., (© The Author(s) 2025. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Purpose: Reflex syncope is a burdensome disease with considerable repercussions on the quality of life. Tilt training is a therapeutic option, but evidence on this topic is scarce and outdated. Hyperventilation is oftentimes associated with reflex syncope. This study aimed to evaluate the effectiveness of tilt training in patients with reflex syncope and study the association between reflex syncope and hyperventilation., Methods: Patients referred for tilt training after a positive tilt test from July 2014 to March 2021 were included in a single-center, retrospective registry. Demographic characteristics and outcomes of the program were collected. The response of tilt training on (pre)syncope recurrence and the association with hyperventilation were studied., Results: A total of 173 patients were included. The median age was 27 [17-48] years. Patients needed 2 [1-3] sessions to reach the first negative tilt training. The tilt training program was successfully completed by 65% of patients. An additional 3% reported no complaints in daily life, despite remaining symptomatic during tilt training. Another therapy was initiated in 10% of patients, while 21% dropped out of the tilt training. Presyncope recurred in 21% of patients during a follow-up period of 21 months [16-23]. Concomitant hyperventilation was suspected in 24%. Among these patients, 74% were referred for a hyperventilation provocation test, which confirmed the diagnosis in 82%., Conclusion: We report a reasonable success of tilt training in a contemporary cohort of patients. In patients completing the tilt training program, presyncope, and syncope recurrence was low. Concomitant hyperventilation seems prevalent in patients with reflex syncope and warrants specific attention and treatment., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Hornikx, Haemers, Stans, Robyns, Garweg, Ector, Vandenberk and Willems.)

Background: Recurrence after atrial fibrillation (AF) ablation is frequent. Monitoring with long-term electrocardiograms (ECGs) is constrained by limited monitoring time, measurement dispersion, and cost. Selected photoplethysmography (PPG) smartphone applications have demonstrated excellent accuracy for AF detection and could mitigate these limitations., Objective: We aimed to compare the effectiveness of digital follow-up using a PPG-based smartphone application against conventional ECG-based follow-up for the detection of atrial arrhythmia recurrence after ablation., Methods: Patients undergoing AF ablation were consecutively enrolled and monitored by a 24-hour ECG at 3, 6, and 12 months on top of the ECGs conducted for clinical indications (conventional follow-up). In addition, patients were instructed to perform PPG measurements twice daily or whenever symptoms were perceived during the course of 1 year (digital follow-up)., Results: In total, 96 patients (69% male; mean age, 64 ± 9 years) performed 39,895 PPG measurements. The compliance rate (number performed/prescribed) was 92.6% for ECGs and 78.2% for PPG recordings. After 1 year of follow-up, atrial arrhythmia recurrence was detected in 17.7% of patients by conventional follow-up and in 38.5% of patients by digital follow-up (odds ratio, 3.4; 95% confidence interval [CI], 1.7-7.1). The CI lower limit exceeded the predefined noninferiority margin (P for noninferiority > .001). Hence, superiority was tested (P for superiority = .001). The negative predictive value of digital follow-up for atrial arrhythmia detected with conventional follow-up was 98.3% (95% CI, 90.9%-99.9%)., Conclusion: Digital rhythm follow-up using a smartphone application with PPG was noninferior to conventional follow-up in detecting atrial arrhythmia recurrence between 3 and 12 months after ablation. Moreover, digital follow-up significantly increased the detection of atrial arrhythmia., Competing Interests: Disclosures The authors have no conflicts of interest to disclose., (Copyright © 2024 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Competing Interests: Disclosures The authors have no conflicts of interest to disclose.

Aims: Photoplethysmography- (PPG) based smartphone applications facilitate heart rate and rhythm monitoring in patients with paroxysmal and persistent atrial fibrillation (AF). Despite an endorsement from the European Heart Rhythm Association, validation studies in this setting are lacking. Therefore, we evaluated the accuracy of PPG-derived heart rate and rhythm classification in subjects with an established diagnosis of AF in unsupervised real-world conditions., Methods and Results: Fifty consecutive patients were enrolled, 4 weeks before undergoing AF ablation. Patients used a handheld single-lead electrocardiography (ECG) device and a fingertip PPG smartphone application to record 3907 heart rhythm measurements twice daily during 8 weeks. The ECG was performed immediately before and after each PPG recording and was given a diagnosis by the majority of three blinded cardiologists. A consistent ECG diagnosis was exhibited along with PPG data of sufficient quality in 3407 measurements. A single measurement exhibited good quality more often with ECG (93.2%) compared to PPG (89.5%; P < 0.001). However, PPG signal quality improved to 96.6% with repeated measurements. Photoplethysmography-based detection of AF demonstrated excellent sensitivity [98.3%; confidence interval (CI): 96.7-99.9%], specificity (99.9%; CI: 99.8-100.0%), positive predictive value (99.6%; CI: 99.1-100.0%), and negative predictive value (99.6%; CI: 99.0-100.0%). Photoplethysmography underestimated the heart rate in AF with 6.6 b.p.m. (95% CI: 5.8 b.p.m. to 7.4 b.p.m.). Bland-Altman analysis revealed increased underestimation in high heart rates. The root mean square error was 11.8 b.p.m., Conclusion: Smartphone applications using PPG can be used to monitor patients with AF in unsupervised real-world conditions. The accuracy of AF detection algorithms in this setting is excellent, but PPG-derived heart rate may tend to underestimate higher heart rates., Competing Interests: Conflict of interest: None declared., (© The Author(s) 2024. Published by Oxford University Press on behalf of the European Society of Cardiology.)

The autonomic nervous system plays a crucial role in atrial fibrillation pathophysiology. Parasympathetic hyperactivity result in a shortening of the action potential duration, a reduction of the conduction wavelength, and as such facilitates reentry in the presence of triggers. Further, autonomic remodeling of atrial myocytes in AF includes progressive sympathetic hyperinnervation by increased atrial sympathetic nerve density and sympathetic atrial nerve sprouting. Knowledge on the pathophysiological process in AF, including the contribution of the autonomic nervous system, may in the near future guide personalized AF management. This review focuses on the role of the autonomic nervous system in atrial fibrillation pathophysiology and non-invasive assessment of the autonomic nervous system., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (© 2024 Vandenberk, Haemers and Morillo.)

Background: Leadless pacemakers (PMs) were recently introduced to overcome lead-related complications. They showed high safety and efficacy profiles. Prospective studies assessing long-term safety on cardiac structures are still missing., Objective: The purpose of this study was to compare the mechanical impact of Micra with conventional PM on heart function., Methods: We conducted a non-inferiority trial in patients with an indication for single chamber ventricular pacing. Patients were 1:1 randomized to undergo implantation of either Micra or conventional monochamber ventricular pacemaker (PM). Patients underwent echocardiography at baseline, 6 and 12 months after implantation. Analysis included left ventricular ejection fraction (LVEF), global longitudinal strain (GLS) and valve function. N-terminal-pro hormone B-type natriuretic peptide (NT-pro-BNP) levels were measured at baseline and 12 months., Results: Fifty-one patients (27 in Micra group and 24 in conventional group) were included. Baseline characteristics were similar for both groups. At 12 months, (1) the left ventricular function as assessed by LVEF and GLS worsened similarly in both groups (∆LVEF -10 ± 7.3% and ∆GLS +5.7 ± 6.4 in Micra group vs. -13.4 ± 9.9% and +5.2 ± 3.2 in conventional group) (p = 0.218 and 0.778, respectively), (2) the severity of tricuspid valve regurgitation was significantly lower with Micra than conventional pacing (p = 0.009) and (3) median NT-pro-BNP was lower in Micra group (970 pg/dL in Micra group versus 1394 pg/dL in conventional group, p = 0.041)., Conclusion: Micra is non inferior to conventional PMs concerning the evolution of left ventricular function at 12-month follow-up. Our data suggest that Micra has a comparable mechanical impact on the ventricular systolic function but resulted in less valvular dysfunction., (© 2023 Wiley Periodicals LLC.)

Aims: The aim of this study is to determine the feasibility, detection rate, and therapeutic implications of large-scale smartphone-based screening for atrial fibrillation (AF)., Methods and Results: Subjects from the general population in Belgium were recruited through a media campaign to perform AF screening during 8 consecutive days with a smartphone application. The application analyses photoplethysmography traces with artificial intelligence and offline validation of suspected signals to detect AF. The impact of AF screening on medical therapy was measured through questionnaires. Atrial fibrillation was detected in the screened population ( n = 60.629) in 791 subjects (1.3%). From this group, 55% responded to the questionnaire. Clinical AF [AF confirmed on a surface electrocardiogram (ECG)] was newly diagnosed in 60 individuals and triggered the initiation of anti-thrombotic therapy in 45%, adjustment of rate or rhythm controlling strategies in 62%, and risk factor management in 17%. In subjects diagnosed with known AF before screening, a positive screening result led to these therapy adjustments in 9%, 39%, and 11%, respectively. In all subjects with clinical AF and an indication for oral anti-coagulation (OAC), OAC uptake increased from 56% to 74% with AF screening. Subjects with clinical AF were older with more co-morbidities compared with subclinical AF (no surface ECG confirmation of AF) ( P < 0.001). In subjects with subclinical AF ( n = 202), therapy adjustments were performed in only 7%., Conclusion: Smartphone-based AF screening is feasible at large scale. Screening increased OAC uptake and impacted therapy of both new and previously diagnosed clinical AF but failed to impact risk factor management in subjects with subclinical AF., Competing Interests: Conflict of interest: H.G. is supported as pre-doctoral strategic basic research fellow by the Fund for Scientific Research Flanders (FWO 1S83221N). F.H.V. is supported by the Special Research Fund (BOF) of Hasselt University (BOF19PD04). T.P and S.E. reported serving as employees for Qompium NV, the company that holds the exclusive rights to FibriCheck©. P.VDV. holds personal stock in Qompium NV (Belgium) and participates an unpaid role in the advisory board of Qompium. P.V. receives fees form Daiichi-Sankyo, Boehringer Ingelheim, and Pfizer. M.R. receives fees from Novartis and Bayer. No other conflicts of interest were reported., (© The Author(s) 2023. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Background: Atrial fibrillation (AF) may occur asymptomatically and can be diagnosed only with electrocardiography (ECG) while the arrhythmia is present., Objectives: The aim of this study was to independently validate the approach of using artificial intelligence (AI) to identify underlying paroxysmal AF from a 12-lead ECG in sinus rhythm (SR)., Methods: An AI algorithm was trained to identify patients with underlying paroxysmal AF, using electrocardiographic data from all in- and outpatients from a single center with at least 1 ECG in SR. For patients without AF, all ECGs in SR were included. For patients with AF, all ECGs in SR starting 31 days before the first AF event were included. The patients were randomly allocated to training, internal validation, and testing datasets in a 7:1:2 ratio. In a secondary analysis, the AF prevalence of the testing group was modified. Additionally, the performance of the algorithm was validated at an external hospital., Results: The dataset consisted of 494,042 ECGs in SR from 142,310 patients. Testing the model on the first ECG of each patient (AF prevalence 9.0%) resulted in accuracy of 78.1% (95% CI: 77.6%-78.5%), area under the receiver-operating characteristic curve of 0.87 (95% CI: 0.86-0.87), and area under the precision recall curve (AUPRC) of 0.48 (95% CI: 0.46-0.50). In a low-risk group (AF prevalence 3%), the AUPRC decreased to 0.21 (95% CI: 0.18-0.24). In a high-risk group (AF prevalence 30%), the AUPRC increased to 0.76 (95% CI: 0.75-0.78). This performance was robust when validated in an external hospital., Conclusions: The approach of using an AI-enabled electrocardiographic algorithm for the identification of patients with underlying paroxysmal AF from ECGs in SR was independently validated., Competing Interests: Funding Support and Author Disclosures Dr Gruwez is supported as predoctoral strategic basic research fellow by the Fund for Scientific Research Flanders (FWO 1S83221N). All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2023 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Aims: Diagnosis of Long QT syndrome (LQTS) is based on prolongation of the QT interval corrected for heart rate (QTc) on surface ECG and genotyping. However, up to 25% of genotype positive patients have a normal QTc interval. We recently showed that individualized QT interval (QTi) derived from 24 h holter data and defined as the QT value at the intersection of an RR interval of 1,000 ms with the linear regression line fitted through QT-RR data points of each individual patient was superior over QTc to predict mutation status in LQTS families. This study aimed to confirm the diagnostic value of QTi, fine-tune its cut-off value and evaluate intra-individual variability in patients with LQTS., Methods: From the Telemetric and Holter ECG Warehouse, 201 recordings from control individuals and 393 recordings from 254 LQTS patients were analysed. Cut-off values were obtained from ROC curves and validated against an in house LQTS and control cohort., Results: ROC curves indicated very good discrimination between controls and LQTS patients with QTi, both in females (AUC 0.96) and males (AUC 0.97). Using a gender dependent cut-off of 445 ms in females and 430 ms in males, a sensitivity of 88% and specificity of 96% were achieved, which was confirmed in the validation cohort. No significant intra-individual variability in QTi was observed in 76 LQTS patients for whom at least two holter recordings were available (483 ± 36 ms vs. 489 ± 42 ms, p  = 0.11)., Conclusions: This study confirms our initial findings and supports the use of QTi in the evaluation of LQTS families. Using the novel gender dependent cut-off values, a high diagnostic accuracy was achieved., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The handling editor JE is currently organizing a Research Topic with the author BV., (© 2023 Robyns, Nuyens, Vandenberk, Haemers, Breckpot, Garweg, Ector and Willems.)

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., (© 2021 Wiley Periodicals LLC.)

Aims: This study aims to compare the performance of physicians to detect atrial fibrillation (AF) based on photoplethysmography (PPG), single-lead ECG and 12-lead ECG, and to explore the incremental value of PPG presentation as a tachogram and Poincaré plot, and of algorithm classification for interpretation by physicians. Methods and Results: Email invitations to participate in an online survey were distributed among physicians to analyse almost simultaneously recorded PPG, single-lead ECG and 12-lead ECG traces from 30 patients (10 in sinus rhythm (SR), 10 in SR with ectopic beats and 10 in AF). The task was to classify the readings as 'SR', 'ectopic/missed beats', 'AF', 'flutter' or 'unreadable'. Sixty-five physicians detected or excluded AF based on the raw PPG waveforms with 88.8% sensitivity and 86.3% specificity. Additional presentation of the tachogram plus Poincaré plot significantly increased sensitivity and specificity to 95.5% ( P < 0.001) and 92.5% ( P < 0.001), respectively. The algorithm information did not further increase the accuracy to detect AF (sensitivity 97.5%, P = 0.556; specificity 95.0%, P = 0.182). Physicians detected AF on single-lead ECG tracings with 91.2% sensitivity and 93.9% specificity. Diagnostic accuracy was also not optimal on full 12-lead ECGs (93.9 and 98.6%, respectively). Notably, there was no significant difference between the performance of PPG waveform plus tachogram and Poincaré, compared to a single-lead ECG to detect or exclude AF (sensitivity P = 0.672; specificity P = 0.536). Conclusion: Physicians can detect AF on a PPG output with equivalent accuracy compared to single-lead ECG, if the PPG waveforms are presented together with a tachogram and Poincaré plot and the quality of the recordings is high., Competing Interests: SE and TP are employed by Qompium NV. DD received speaker honoraria and/or travel grants from Abbott, Astra-Zeneca, Bayer, Biotronic, Boehringer-Ingelheim, Boston Scientific, Medtronic, Pfizer and Zoll. HH did receive personal fees from Biotronik and Pfizer-BMS. He received unconditional research grants through the University of Antwerp and/or the University of Hasselt from Bayer, Boehringer-Ingelheim, Bracco Imaging Europe, Abbott, Medtronic, Biotronik, Daicchi-Sankyo, Pfizer- BMS, and Boston-Scientific, all outside the scope of this work. MM received speaker honoraria and/or travel grants from Biosense Webster, Abbott, Biotronik, Zoll, Boston Scientific, Daiichi Sankyo, Bayer, Pfizer, Amomed as well as research grants from Biosense Webster, none of which are relevant to the manuscript. PV holds stock in Qompium NV. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Gruwez, Evens, Proesmans, Duncker, Linz, Heidbuchel, Manninger, Vandervoort, Haemers and Pison.)

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<.001). In the second month of follow-up, compliance was significantly lower with 2.2 (SD 0.7) measurements per day versus 3.0 (SD 0.8) measurements per day in the first month (P=.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., (©Marie Lamberigts, Lucas Van Hoof, Tine Proesmans, Pieter Vandervoort, Lars Grieten, Peter Haemers, Filip Rega. Originally published in JMIR mHealth and uHealth (http://mhealth.jmir.org), 15.04.2021.)

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., (© 2020 Wiley Periodicals LLC.)

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., (© The Author(s) 2020. Published by Oxford University Press on behalf of the European Society of Cardiology.)

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 < .001) or an episode of heart failure (P = .02) and negatively correlated with the number of procedures performed by the operator (P < .001). After multivariable analysis, only the presence of a prominent septal component of the septomarginal trabeculation (P < .001) and the number of procedures performed by the operator (P < .001) were associated with the implant procedure time., Conclusions: In our experience, implant procedure time of a Micra leadless pacemaker depended on the presence of a prominent septal component of the septomarginal trabeculation and operator experience., (© 2020 Wiley Periodicals LLC.)

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 < .001). Pacing threshold and R-wave amplitude did not differ over time in either position. The median narrowest paced QRS duration was observed in the RVOT (142 ms) compared to mid-septal (159 ms; P < .001), and apical position (181 ms; P < .001)., Conclusion: Implantation of the Micra TPS in the RVOT is safe and feasible. Electrical performance over time was comparable to mid-septal and apical positions. The narrowest paced QRS complexes is achieved with RVOT pacing., (© 2019 Wiley Periodicals, Inc.)

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.

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 (MI adjacent , reduced function, reduced perfusion reserve), and the remote myocardium (MI remote , minimal functional deficit, maintained perfusion). Interstitial and perivascular fibrosis, and increase of collagen type I, was only observed in the MI adjacent . Fb activated protein-alpha (FAP-α) was enriched in MI adjacent compared to MI remote . TGF-β1, which triggers Fb differentiation, was upregulated in both MI adjacent and MI remote , whereas lysyl oxidase, a regulator of collagen cross-linking, and the proteoglycans decorin and biglycan were only increased in the MI adjacent . Fb isolated and cultured for 4 days had myoFb characteristics with little difference between MI remote and MI adjacent , 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.

Aims: 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., Methods and Results: 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%, P < 0.001). 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., Conclusion: 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., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2015. For permissions please email: journals.permissions@oup.com.)

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.

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.