BACKGROUND AND AIM:Randomized trials conducted in the early 2000s established the survival benefit of primary prevention implantable cardioverter-defibrillator (ICD) therapy in patients with reduced left ventricular ejection fraction (LVEF) after myocardial infarction. However, management of myocardial infarction and heart failure has substantially evolved since that time. We investigated whether the estimated association between primary prevention ICD implantation in post-myocardial infarction patients with reduced LVEF and mortality reduction has changed over time. METHODS:We analyzed individual participant data from 32,214 patients with LVEF ≤35% after myocardial infarction included in the PROFID pooled cohort, comprising 7,477 patients carrying a primary prevention ICD (ICD patients) and 24,737 patients without an ICD (non-ICD patients). The primary endpoint was all-cause mortality. Propensity scores were estimated using multivariable logistic regression including age, sex, LVEF, renal function, and diabetes, and overlap weighting was applied to balance treatment groups. Time period-specific analyses were performed across three prespecified time periods defined by inclusion year: 1995-2004, 2005-2014, and 2015-2020. Weighted cumulative mortality curves were generated for each time period. Temporal changes in the estimated association between ICD implantation and mortality reduction were assessed using a weighted Cox proportional hazards model. RESULTS:A total of 12,097 deaths occurred during a mean follow-up of 43.7 months. The estimated association between ICD implantation and mortality changed significantly across time (P for interaction <0.001). In weighted time period-specific analyses, the estimated mortality reduction associated with ICD implantation progressively decreased over more recent periods. The hazard ratio for ICD versus non-ICD patients was 0.54 (95% CI 0.47-0.62; P<0.001) in 1995-2004, 0.67 (95% CI 0.62-0.72; P<0.001) in 2005-2014, and 0.89 (95% CI 0.73-1.07; P=0.221) in 2015-2020, with negligible separation of the weighted cumulative mortality curves in the most recent time period. CONCLUSIONS:In this analysis including a large cohort of post-myocardial infarction patients with reduced LVEF, the estimated mortality reduction associated with primary prevention ICD implantation progressively decreased over time.

Background:Vision-enabled large language models (VE-LLMs) have the potential to provide flexible and explainable medical image interpretation. However, their real-world performance on clinical data, such as 12-lead electrocardiograms (ECGs), has not been systematically assessed. Objective:This study aimed to evaluate the diagnostic accuracy and reliability of state-of-the-art generalist VE-LLMs in interpreting real-world ECG images. Methods:We tested 6 generalist VE-LLMs (ChatGPT-5, ChatGPT-4, Gemini 2.5, Copilot, Claude Sonnet-4, and Claude Opus-4.1) using 70 deidentified ECG images. A standardized prompt requested 9 determinations: rhythm, first-degree atrioventricular (AV) block, intraventricular conduction block and pattern, corrected QT (QTc) prolongation, premature atrial and ventricular contractions, ischemic ST-segment deviation, and axis deviation. An expert consensus served as the reference standard. Moreover, 2 image-based ECG-specialized LLMs (PULSE-7B and ECG-Instruct-Llama-3.2-11B-Vision) were tested for exploratory comparison. Model outputs were evaluated using overall and per-category diagnostic metrics. Results:Overall balanced accuracy across generalist models ranged from 50.1% to 61.8% (Cochran Q, P<.001). ChatGPT-5 achieved the highest balanced accuracy (61.8%) but had the slowest response time (median 276, IQR 110-407 s), whereas Copilot responded within a median of 3 (IQR 2-4) seconds. Balanced accuracy for rhythm classification ranged from 38.6% to 55.8%, but sensitivity for atrial fibrillation among generalist models was ≤11.1%, detecting either none or only 1 of the 9 cases. Detection of first-degree AV block (sensitivity 0%-22%; 0/9 to 2/9) and QTc prolongation (sensitivity 0%-45.5%; 0/22 to 10/22) was poor. Intraventricular block was identified with up to 67.8% balanced accuracy, but correct subtype assignment was ≤44% (≤11/25). ST-segment deviation sensitivity was <25% for all generalist models (highest 3/14). Agreement with expert interpretation was low, with Cohen κ indicating poor-to-fair concordance (κ≤0.39). Specialized models achieved overall balanced accuracy of 56.5% (ECG-Instruct-Llama-3.2-11B-Vision) and 64.4% (PULSE-7B), with PULSE-7B showing higher task-specific balanced accuracy in rhythm classification and ectopic beats detection (up to 86.3% and 89.2%, respectively). Conclusions:VE-LLMs showed moderate overall performance but mostly low sensitivity and limited agreement with expert ECG interpretation. Current performance remains inconsistent across models and diagnostic categories and is insufficient to support clinical deployment.

Introduction Cardiovascular disease is a leading cause of death worldwide, of which coronary artery disease is the most common form. Sudden cardiac death (SCD) is a serious complication following acute myocardial infarction (MI), accounting for the highest percentage of all deaths in this population. Currently implantable cardioverter-defibrillators (ICDs) provide an acceptable method of primary prevention of SCD. However, the current literature is heterogeneous with regard to studies evaluating the benefits of ICDs for the primary prevention of SCD after MI, particularly relating to the timing of ICD implantation, risk stratification of patients for ICD implant selection and reporting non-rhythmic deaths after ICD implantation.Methods and analysis A meta-analysis will be performed to estimate the pooled effect size of randomised controlled trials (RCTs) examining the relationship between prophylactic transvenous ICD (TV-ICD) implantation and other medical therapies for primary prevention of SCD after MI. A comprehensive literature search and review will be performed using electronic medical databases including Scopus, Ovid MEDLINE, EMBASE (Ovid Platform), Cochrane Central Register of Controlled Trials (CENTRAL), PubMed, ProQuest (Health and Medicine) and CINAHL (EBSCO) from January 1980 to June 2025. The literature search will be limited to peer-reviewed original studies carried out in human subjects and published in English. Type of study design will be limited to RCTs. The systematic review and meta-analysis will be developed according to the Joanna Briggs Institute Manual for Evidence Synthesis (2024 edition) and conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis 2020 guidelines. Data analysis will be performed according to a structured and predetermined analysis plan. The primary outcome of the study will be all-cause-mortality, for which Hazard Ratios (HRs) will be reported as a measure of effect with 95% CI. Based on data availability, subgroup analysis will be carried out. The effect sizes will be reported based on a random effects model.Expected study outcomes and dissemination This systematic review and meta-analysis will evaluate and provide primary evidence for the effectiveness of prophylactic implantation of TV-ICDs on all-cause mortality in patients who experienced MI, aiming for primary prevention of SCD after MI. The primary prevention of SCD after MI is an important goal to reduce community incidence of out-of-hospital cardiac arrests, improving patient survival rates and their quality of life after MI. Out-of-hospital cardiac arrests currently have a survival rate of less than 10% and could result in long-lasting neurological damage in those who survive.PROSPERO registration CRD42023456995.

BACKGROUND:The Extravascular Implantable Cardioverter-Defibrillator (EV-ICD) utilizes a substernal lead to provide defibrillation and anti-tachycardia pacing (ATP) while avoiding transvenous complications. General anesthesia (GA) was applied for implantation procedures in the EV-ICD pivotal trial and is currently recommended by the manufacturer. However, GA carries specific risks and consumes significant resources. This study evaluates the feasibility, safety, and procedural efficiency of EV-ICD implantation performed under cardiologist-administered deep sedation with noninvasive ventilation (DS-NIV) compared to standard GA. METHODS:We retrospectively analyzed 24 consecutive patients undergoing EV-ICD implantation in our center. Patients received either GA (n = 14) or DS-NIV (n = 10) using a propofol-ketamine protocol delivered by cardiologists. Analyses focused on peri-procedural feasibility and safety, procedural workflow and anesthesia characteristics, and early device electrical performance. RESULTS:No anesthesia-related complications occurred in either group. The DS-NIV group demonstrated significantly shorter wheels-to-incision times (median: 45 vs. 70 min, p = 0.022), whereas the procedural duration did not differ significantly from the GA group. Patients receiving DS-NIV required fewer vasopressors (60% vs. 100%, p = 0.024) despite higher propofol infusion rates (800 vs. 350 mg/h, P<0.001). Defibrillation testing success and electrical parameters were comparable. In a median follow-up of 182 days two patients received appropriate EV-ICD therapies and no inappropriate ATP or shocks were delivered. CONCLUSION:EV-ICD implantation under cardiologist-administered DS-NIV appears to be feasible and safe, offering improved workflow efficiency compared to GA. These findings support deep sedation as a practical alternative in experienced centers, potentially expanding access to EV-ICD therapy.

In this case we experienced a narrowing of the QRS complex during ablation of premature ventricular contractions in a patient with a left bundle branch block.

Background:Arrhythmia-induced cardiomyopathy (AiCM) is an increasingly recognized cause of heart failure. Atrial fibrillation and premature ventricular contractions are common causes of AiCM. Further, the use of wearable technology in arrhythmia detection is increasing steadily. In this case, we report on a patient suffering from AiCM as a result of frequent premature atrial contractions (PACs) detected by a wearable device. Case summary:A 34-year-old male, with no prior medical history, presented after his smartwatch detected frequent 'heart arrhythmias.' An initial electrocardiogram showed sinus rhythm with frequent PACs. Further evaluation revealed left ventricular dysfunction [left ventricular ejection fraction (LVEF) 35%]. Non-invasive tests ruled out coronary artery disease. Although the patient was initially asymptomatic, his condition worsened with a decline in LVEF to 15% despite optimal medical therapy. High-resolution 3D mapping identified the ectopic focus in the left inferior pulmonary vein, and radiofrequency ablation successfully eliminated the PACs. At the six-month follow-up, the patient was symptom-free with a recovered LVEF of 50%. Discussion:This case highlights the potential for frequent PACs to induce AiCM. Although PACs are typically considered benign, in this case, the high PAC burden led to significant left ventricular dysfunction. The successful resolution of the patient's symptoms and the improvement in heart function after radiofrequency ablation demonstrate the reversibility of AiCM caused by PACs if treated early. Importantly, this case underscores the emerging role of wearable technologies, like smartwatches, in the early detection of arrhythmias, enabling timely intervention to prevent the progression of heart failure.

During cryoballon pulmonary vein isolation (PVI) complete occlusion of the pulmonary vein ostia during the freeze cycles is mandatory. Typically, PV occlusion is assessed by contrast injection under fluoroscopy. Using an update for the Cryo Console it is possible to directly visualize occlusion pressure as an indicator of complete PV occlusion during cryoballoon procedures. In this study, we compared PV pressure monitoring during cryoballoon PVI to a conventional approach regarding procedural outcomes. We retrospectively analysed the procedural data of 50 patients (25 patients with pressure-guided PVI and 25 patients with contrast-guided PVI) treated with cryoballoon PVI in our centre. Complete PV occlusion in the pressure-guided group was defined as an abrupt change in the pressure waveform with a loss of the a-wave after advancing the cryoballoon to the PV ostium. We observed comparable results regarding procedural time, left atrial dwell time or fluoroscopy time when comparing the pressure guided to our conventional approach. Moreover, there were no differences regarding acute procedural effectivity or freeze cycle characteristics. As expected, a significant reduction of contrast use was achieved in the pressure measurement group (10.4 vs. 25.5 ml, p < 0.0001). Monitoring complete PV occlusion by visualizing the occlusion pressure is feasible. Acute procedural outcome was comparable to our standard approach using contrast injection to verify complete PV occlusion. Most importantly, a significant reduction in contrast use could be achieved which has to be confirmed in larger patient cohorts.

Cardioneuroablation is a treatment option for patients with recurrent vasovagal syncope (VVS). Ablation targets of parasympathetic ganglionated plexi (GP) adjacent to the right and left atrial walls and distal endocardial inputs of these GP can be identified both by their anatomical localization and by intracardiac mapping of fragmented electrogram signals. In this case of a successful cardioneuroablation of a 22-year-old patient suffering from recurrent VVS, a new algorithm for automatic mapping of fragmented signals (CARTO Elevate Module, Biosense Webster) was used to identify areas of GP. In this first experience, automatic tags of fragmented signals were matching well with anatomically guided ablation points. This new tool for automatic identification of fragmented signals may facilitate and improve cardioneuroablation procedures.

Background Data comparing remote magnetic catheter navigation (RMN) with manual catheter navigation in combination with contact force sensing (MCN-CF) ablation of atrial fibrillation (AF) is lacking. The primary aim of the present retrospective comparative study was to compare the outcome of RMN versus (vs.) MCN-CF ablation of AF with regards to AF recurrence. Secondary aim was to analyze periprocedural risk, ablation characteristics and repeat procedures. Methods We retrospectively analyzed 452 patients undergoing a total of 605 ablations of AF: 180 patients were ablated using RMN, 272 using MCN-CF. Results Except body mass index there was no significant difference between groups at baseline. After a mean 1.6 ± 1.6 years of follow-up and 1.3 ± 0.4 procedures, 81% of the patients in the MCN-CF group remained free of AF recurrence compared to 53% in the RMN group ( P < 0.001). After analysis of 153 repeat ablations (83 MCN-RF vs. 70 RMN; P = 0.18), there was a significantly higher reconnection rate of pulmonary veins after RMN ablation ( P < 0.001). In multivariable Cox-regression analysis, RMN ablation ( P < 0.001) and left atrial diameter ( P = 0.013) was an independent risk factor for AF recurrence. Procedure time, radiofrequency application time and total fluoroscopy time and fluoroscopy dose were higher in the RMN group without difference in total number of ablation points. Complication rates did not differ significantly between groups ( P = 0.722). Conclusions In our retrospective comparative study, the AF recurrence rate and pulmonary vein reconnection rate is significantly lower with more favorable procedural characteristics and similar complication rate utilizing MCN-CF compared to RMN.

Background New methods to identify patients who benefit from a primary prophylactic implantable cardioverter‐defibrillator (ICD) are needed. T‐wave alternans (TWA) has been shown to associate with arrhythmogenesis of the heart and sudden cardiac death. We hypothesized that TWA might be associated with benefit from ICD implantation in primary prevention. Methods and Results In the EU‐CERT‐ICD (European Comparative Effectiveness Research to Assess the Use of Primary Prophylactic Implantable Cardioverter‐Defibrillators) study, we prospectively enrolled 2327 candidates for primary prophylactic ICD. A 24‐hour Holter monitor reading was taken from all recruited patients at enrollment. TWA was assessed from Holter monitoring using the modified moving average method. Study outcomes were all‐cause death, appropriate shock, and survival benefit. TWA was assessed both as a contiguous variable and as a dichotomized variable with cutoff points <47 μV and <60 μV. The final cohort included 1734 valid T‐wave alternans samples, 1211 patients with ICD, and 523 control patients with conservative treatment, with a mean follow‐up time of 2.3 years. TWA ≥60 μV was a predicter for a higher all‐cause death in patients with an ICD on the basis of a univariate Cox regression model (hazard ratio, 1.484 [95% CI, 1.024–2.151]; P =0.0374; concordance statistic, 0.51). In multivariable models, TWA was not prognostic of death or appropriate shocks in patients with an ICD. In addition, TWA was not prognostic of death in control patients. In a propensity score–adjusted Cox regression model, TWA was not a predictor of ICD benefit. Conclusions T‐wave alternans is poorly prognostic in patients with a primary prophylactic ICD. Although it may be prognostic of life‐threatening arrhythmias and sudden cardiac death in several patient populations, it does not seem to be useful in assessing benefit from ICD therapy in primary prevention among patients with an ejection fraction of ≤35%.

HomeCirculation: Arrhythmia and ElectrophysiologyAhead of PrintPulsed Field Ablation of Atrial Fibrillation and Atrial Tachycardia in Adult Patients With Congenital Heart Disease No AccessLetterRequest AccessAboutView PDFSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toNo AccessLetterRequest AccessPulsed Field Ablation of Atrial Fibrillation and Atrial Tachycardia in Adult Patients With Congenital Heart Disease Ulrich Krause, Leonard Bergau, Markus Zabel, Heike E. Schneider, Matthias J. Müller and Thomas Paul Ulrich KrauseUlrich Krause Correspondence to: Ulrich Krause, MD, Department of Pediatric Cardiology and Intensive Care Medicine, University Medical Center, Georg-August-University Göttingen, Robert-Koch-Str. 40, 37099 Göttingen, Germany. Email E-mail Address: [email protected] https://orcid.org/0000-0003-3673-165X Department of Pediatric Cardiology, Intensive Care Medicine and Neonatology, University Medical Center, Georg-August-University Göttingen, Germany. (U.K., H.E.S., M.J.M., T.P.) , Leonard BergauLeonard Bergau https://orcid.org/0000-0001-7025-9315 Department of Cardiology and Pneumology, Heart Center, University Medical Center, Georg-August-University Göttingen, Germany. (L.B., M.Z.) , Markus ZabelMarkus Zabel https://orcid.org/0000-0003-0895-4602 Department of Cardiology and Pneumology, Heart Center, University Medical Center, Georg-August-University Göttingen, Germany. (L.B., M.Z.) , Heike E. SchneiderHeike E. Schneider https://orcid.org/0000-0001-5946-4342 Department of Pediatric Cardiology, Intensive Care Medicine and Neonatology, University Medical Center, Georg-August-University Göttingen, Germany. (U.K., H.E.S., M.J.M., T.P.) , Matthias J. MüllerMatthias J. Müller https://orcid.org/0000-0001-9511-1093 Department of Pediatric Cardiology, Intensive Care Medicine and Neonatology, University Medical Center, Georg-August-University Göttingen, Germany. (U.K., H.E.S., M.J.M., T.P.) and Thomas PaulThomas Paul https://orcid.org/0000-0003-1895-6345 Department of Pediatric Cardiology, Intensive Care Medicine and Neonatology, University Medical Center, Georg-August-University Göttingen, Germany. (U.K., H.E.S., M.J.M., T.P.) Originally published23 Apr 2024https://doi.org/10.1161/CIRCEP.123.012698Circulation: Arrhythmia and Electrophysiology. 2024;0:e012698FootnotesFor Sources of Funding and Disclosures, see page XXX.Correspondence to: Ulrich Krause, MD, Department of Pediatric Cardiology and Intensive Care Medicine, University Medical Center, Georg-August-University Göttingen, Robert-Koch-Str. 40, 37099 Göttingen, Germany. Email ukrause1@gwdg.de eLetters(0)eLetters should relate to an article recently published in the journal and are not a forum for providing unpublished data. Comments are reviewed for appropriate use of tone and language. Comments are not peer-reviewed. Acceptable comments are posted to the journal website only. Comments are not published in an issue and are not indexed in PubMed. Comments should be no longer than 500 words and will only be posted online. References are limited to 10. Authors of the article cited in the comment will be invited to reply, as appropriate.Comments and feedback on AHA/ASA Scientific Statements and Guidelines should be directed to the AHA/ASA Manuscript Oversight Committee via its Correspondence page.Sign In to Submit a Response to This Article Previous Back to top Next FiguresReferencesRelatedDetails Advertisement Article InformationMetrics © 2024 American Heart Association, Inc.https://doi.org/10.1161/CIRCEP.123.012698PMID: 38651354 Originally publishedApril 23, 2024 Keywordsatrial fibrillationcoronary vesselsheart defects, congenitalpulmonary veinstachycardiaPDF download Advertisement SubjectsAtrial FibrillationCongenital Heart Disease

Pulsed-field energy (PFA) and very high-power short-duration radiofrequency (vHPSD-RF) are two novel ablation methods for pulmonary vein isolation (PVI). Both PFA and vHPSD-RF show promise for improving efficacy, safety, and reducing procedure durations. However, direct comparisons between these two techniques are scarce. Retrospective analysis of 82 patients with symptomatic AF. Of these, 52 patients received PFA and 30 received vHPSD-RF (90 W, 4 s) as index procedure. At the 6-month follow-up, AF recurrence occurred in 4 patients following PFA and 5 patients following vHPSD-RF (p-value = 0.138). Significant improvements in the EHRA and NYHA stages were evident in both PFA (p < 0.001 and p = 0.047, respectively) and vHPSD-RF groups (p = 0.007 and p = 0.012, respectively). The total procedure duration and the left atrial dwell time were significantly shorter in the PFA group (64 ± 19 min vs. 99 ± 32 min, p < 0.001 and 41 ± 12 min vs. 62 ± 29 min, p < 0.001, respectively). The fluoroscopy time and dose area product were significantly higher in PFA (14 ± 6 vs. 9 ± 5 min, p < 0.001 and 14 ± 9 vs. 11 ± 9 Gy cm2, p = 0.046, respectively). One patient in the vHPSD-RF group suffered a stroke, not directly linked to the procedure (0 vs. 1 major complication, p = 0.366). Based on this retrospective single-center study, PFA and vHPSD-RF were associated with similar effectiveness and safety profiles. PFA was linked to shorter procedure times and higher radiation exposure compared to vHPSD-RF.

ObjectiveTo test the hypothesis that in recipients of primary prophylactic implantable cardioverter-defibrillators (ICDs), the non-planarity of ECG vector loops predicts (a) deaths despite ICD protection and (b) appropriate ICD shocks.MethodsDigital pre-implant ECGs were collected in 1948 ICD recipients: 21.4% females, median age 65 years, 61.5% ischaemic heart disease (IHD). QRS and T wave three-dimensional loops were constructed using singular value decomposition that allowed to measure the vector loop planarity. The non-planarity, that is, the twist of the three-dimensional loops out of a single plane, was related to all-cause mortality (n=294; 15.3% females; 68.7% IHD) and appropriate ICD shocks (n=162; 10.5% females; 87.7% IHD) during 5-year follow-up after device implantation. Using multivariable Cox regression, the predictive power of QRS and T wave non-planarity was compared with that of age, heart rate, left ventricular ejection fraction, QRS duration, spatial QRS-T angle, QTc interval and T-peak to T-end interval.ResultsQRS non-planarity was significantly (p<0.001) associated with follow-up deaths despite ICD protection with HR of 1.339 (95% CI 1.165 to 1.540) but was only univariably associated with appropriate ICD shocks. Non-planarity of the T wave loop was the only ECG-derived index significantly (p<0.001) associated with appropriate ICD shocks with multivariable Cox regression HR of 1.364 (1.180 to 1.576) but was not associated with follow-up mortality.ConclusionsThe analysed data suggest that QRS and T wave non-planarity might offer distinction between patients who are at greater risk of death despite ICD protection and those who are likely to use the defibrillator protection.

BACKGROUND:Cardiac fibrosis plays a major pathophysiological role in any form of chronic heart disease, and high levels are associated with poor outcome. Diffuse and focal cardiac fibrosis are different subtypes, which have different pathomechanisms and prognostic implications. The total fibrosis burden in endomyocardial biopsy tissue was recently proved to play an independent prognostic role in aortic stenosis patients after transcatheter aortic valve implantation (TAVI).AIMS:Here, for the first time, we aim to assess the specific impact of different fibrosis subtypes on sudden cardiac death (SCD) as a primary reason for cardiovascular mortality after TAVI.METHODS:The fibrosis pattern was assessed histologically in the left ventricular biopsies obtained during TAVI interventions in 161 patients, who received a structured follow-up thereafter.RESULTS:Receiver operating characteristic analyses, performed 6, 12, 24 and 48 months after TAVI, showed diffuse, but not focal, fibrosis as a significant predictor for SCD at all timepoints, with the highest area under the curve at the first time point and a decrease in its SCD predictivity over time. In both multivariate Cox proportional hazards and Fine-Gray competing risk models, including both fibrosis subtypes, as well as age, sex and ejection fraction, high diffuse fibrosis remained statistically significant. Accordingly, it represents an independent SCD predictor, most importantly for the occurrence of early events.CONCLUSIONS:The burden of diffuse cardiac fibrosis plays an important and independent prognostic role regarding SCD early after TAVI. Therefore, the histological evaluation of fibrosis topography has value as a prognostic tool for TAVI patients and may help to tailor individualised approaches to optimise their postinterventional management.

Background and Aims Risk stratification of sudden cardiac death after myocardial infarction and prevention by defibrillator rely on left ventricular ejection fraction (LVEF). Improved risk stratification across the whole LVEF range is required for decision-making on defibrillator implantation. Methods The analysis pooled 20 data sets with 140 204 post-myocardial infarction patients containing information on demographics, medical history, clinical characteristics, biomarkers, electrocardiography, echocardiography, and cardiac magnetic resonance imaging. Separate analyses were performed in patients (i) carrying a primary prevention cardioverter-defibrillator with LVEF <= 35% [implantable cardioverter-defibrillator (ICD) patients], (ii) without cardioverter-defibrillator with LVEF <= 35% (non-ICD patients <= 35%), and (iii) without cardioverter-defibrillator with LVEF > 35% (non-ICD patients >35%). Primary outcome was sudden cardiac death or, in defibrillator carriers, appropriate defibrillator therapy. Using a competing risk framework and systematic internal-external cross-validation, a model using LVEF only, a multivariable flexible parametric survival model, and a multivariable random forest survival model were developed and externally validated. Predictive performance was assessed by random effect meta-analysis. Results There were 1326 primary outcomes in 7543 ICD patients, 1193 in 25 058 non-ICD patients <= 35%, and 1567 in 107 603 non-ICD patients >35% during mean follow-up of 30.0, 46.5, and 57.6 months, respectively. In these three subgroups, LVEF poorly predicted sudden cardiac death (c-statistics between 0.50 and 0.56). Considering additional parameters did not improve calibration and discrimination, and model generalizability was poor. Conclusions More accurate risk stratification for sudden cardiac death and identification of low-risk individuals with severely reduced LVEF or of high-risk individuals with preserved LVEF was not feasible, neither using LVEF nor using other predictors.

Abstract Funding Acknowledgements Type of funding sources: None. Background/Introduction Implantable loop recorders (ILR) are increasingly used for continuous rhythm monitoring following pulmonary vein isolation (PVI) for atrial fibrillation (AF). However, the impact of non-AF episodes in this patient population is unknown. Purpose Firstly, the aim of our study was to asses the incidence of clinically important non-AF events. Secondly, we wanted to identify possible risk factors leading to incidental non-AF events. Methods In this retrospective single center study, all patients implanted with ILR following PVI in our center between 2016 and 2022 were analysed. The indication to ILR implantation and remote monitoring after successful PVI was based on patient preference. Transmissions were carefully reviewed by two independent electrophysiologists. Bradycardic events were defined as documented symptomatic bradycardia, AV-Block II˚, AV-Block III˚ or Sick-Sinus Syndrom. Tachycardic events were defined as documented symptomatic supraventricular tachycardia (non-AF) or ventricular tachycardia >160/min with at least 30 seconds duration. Results A total of 219 patients underwent PVI and consequent ILR implantation. We evaluated a mean 2.1±1.1 years of follow up (FU) with a median 68 events/patient (25th–75th IQR: 13-590 events/patient). Overall, 49 patients (22.4%) developed at least one bradycardic event, 6 patients (2.7%) were later implanted with a pacemaker. In univariate logistic regression analysis age, persistent AF, left atrial diameter and prior cardioversion correlated with an increased risk of bradycardic events. Upon a multivariate logistic regression age and prior cardioversion predicted bradycardic events. At least one tachycardic non-AF event was observed in a total of 9 patients (3.6%). Supraventricular tachycardia was observed by 4 patients (1.8%), one (0.4%) were ablated by an atrioventricular nodal reentry tachycardia (AVNRT), others (1.4%) were ectopic atrial tachycardia treated conservatively. Sustained wide complex tachycardia was recorded in 5 patients (2.2%), thereof two (0.9%) received a secondary prophylactic implantable cardioverter defibrillator (ICD). The multivariate analysis did not show any statistically significant value predicting tachycardic events. Conclusion Use of ILR for rhythm monitoring following PVI could increase the early detection of incidental rhythm events, especially bradycardic episodes. However, to asses this possibly beneficial effect further prospective, multicenter studies are needed.

We report on a 33-year-old patient with Ebstein’s anomaly (EA) of the tricuspid valve who had recurrent episodes of sustained monomorphic ventricular tachycardia (VT). After the first episodes of VT 8 years ago, he had radiofrequency ablation (RFA) of VT within the atrialized right ventricle (aRV) and implantation of an extracardiac implantable cardio-verter defibrillator (

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – EU funding. Main funding source(s): European Community’s 7th Framework Programme (HEALTH-F2-2009-602299) Ministry of Health, Czech Republic Background Three-dimensional (e.g., vectorcardiography) loops of normal physiologic QRS complex and T wave are known to be planar. Non-planarity of these electrocardiogram (ECG) loops was described in cardiac patients, mainly in relation to ischemic heart disease, but predictive values of the extent of non-planarity of the loops have not been systematically researched. Methods Pre-implantation digital ECGs were collected in 1948 cardiac patients (381 females, median age 65, inter-quartile range 56 – 72 years, 62% ischemic heart disease) who obtained an implantable cardioverter-defibrillator (ICD) for primary prophylactic reasons. In each ECG, QRS and T wave 3-dimensional loops were constructed using singular value decomposition and the non-planarity of the loops was measured as the relative power of the 3rd, least significant decomposition component. The non-planarity (i.e., the spatial twist) of the loops was related to all-cause mortality and to appropriate ICD shocks that occurred during the first 5 years after device implantation. This predictive power was compared to that of age, heart rate, left ventricular ejection fraction, QRS duration, spatial QRS-T angle, QTc interval, and T-peak to T-end interval. Results Non-planarity of the QRS loop was significantly associated with follow-up deaths despite ICD protection (p<0.001 both univariably and in multivariable Cox regression analysis) but was less powerfully associated with appropriate ICD shocks. Non-planarity of the T wave loop was significantly associated with appropriate ICD shocks during follow-up (p<0.001 both univariably and in multivariable Cox regression analysis) but was not associated with mortality during follow-up (Table). This was also seen in significant separation of Kaplan-Meier event probability curves (Figure). Conclusions The analysed data of recipients of prophylactic ICDs suggest that non-planarity of QRS complex and T wave loops offers distinction between patients who are at greater risk of death despite ICD protection and those who are likely to utilize the defibrillator protection.

Prevalence of atrial tachycardias (AT) and atrial fibrillation (AF) is increasing in adult patients with congenital heart disease (CHD) significantly contributing to morbidity. Catheter ablation of AT and AF in the adult CHD population is challenging and recurrence is significant. Pulsed field ablation (PFA) is a new, non-thermal energy source for catheter ablation of AF. Due to its inherent properties of creating effective ablation lesions without permanent affection of non-myocardial tissue, it is attractive for the use in the adult CHD population.