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Introduction: Electrophysiological testing has been proposed in the latest European Society of Cardiology (ESC) guidelines for cardiac pacing to identify left bundle branch block (LBBB) patients with infrahisian conduction delay (IHCD) after transcatheter aortic valve replacement (TAVR). While in general IHCD is defined by a His‐ventricular (HV) interval of >55 ms, a cut‐off of ≥70 ms to trigger pacemaker (PM) implantation has been proposed in the latest ESC guidelines. The ventricular pacing (VP) burden during follow‐up in such patients is largely unknown. As such, we aimed to assess the VP burden during follow‐up of patients receiving PM therapy for LBBB after TAVR based on an HV interval > 55 ms and ≥70 ms. Methods: All patients with new‐onset or pre‐existing LBBB after undergoing TAVR at a tertiary referral center underwent EP testing the day after TAVR. In patients with a prolonged HV interval (>55 ms), PM implantation was performed by a trained electrophysiologist in a standardized fashion. All devices were programmed to avoid unnecessary VP by specific algorithms (e.g., AAI‐DDD). Results: 701 patients underwent TAVR at the University Hospital of Basel. One hundred seventy‐seven patients presented with new‐onset or pre‐existing LBBB the day following TAVR and underwent EP testing. An HV interval > 55 ms was found in 58 patients (33%) and an HV interval ≥ 70 ms in 21 patients (12%). 51 patients (mean age 84 ± 6.2 years, 45% women) agreed to receive a PM, out of which 20 (39%) patients had an HV Interval over 70 ms. Atrial fibrillation was present in 53% of the patients. A dual chamber PM was implanted in 39 (77%), and a single chamber PC in 12 (23%) patients, respectively. Median follow‐up was 21 months. The median VP burden overall was 3%. The median VP burden was not significantly different between patients with an HV ≥ 70 ms (6.5 [0.8−52]) and those with an HV between 55 and 69 ms (2 [0−17], p =.23). 31% of patients demonstrated a VP burden < 1%, 27% 1%−5% and 41% > 5%. The median HV intervals in patients with VP burdens < 1%, 1%−5% and >5% were 66 (IQR 62−70) ms, 66 (IQR 63−74) ms and 68 (IQR 60−72) ms, respectively, p =.52. When only assessing patients with an HV interval 55−69 ms, 36% demonstrated a VP burden of <1%, 29% of 1%−5% and 35% of >5%. In patients with an HV Interval ≥ 70 ms, 25% demonstrated a VP burden < 1%, 25% of 1%−5% and 50% of >5% %, p =.64 (Figure). Conclusion: In patients with LBBB after TAVR and IHCD defined by an HV interval > 55 ms, VP burden is relevant in a non‐negligible amount of patients during follow‐up. Further studies are warranted to define the optimal cut‐off value for the HV interval or to develop risk models incorporating HV measurements and other risk factors to trigger PM implantation in patients with LBBB after TAVR. [ABSTRACT FROM AUTHOR]

Introduction: Cardiac resynchronization defibrillator (CRT‐D) as primary prevention is known to reduce mortality. At the time of replacement, higher age and comorbidities may attenuate the benefit of implantable cardioverter‐defibrillator (ICD) therapy. The purpose of this study was to evaluate the progression of comorbidities after implantation and their association with mortality following CRT‐D generator replacement. In addition, a risk score was developed to identify patients at high risk for mortality after replacement. Methods and Results: We identified patients implanted with a primary prevention CRT‐D (n = 648) who subsequently underwent elective generator replacement (n = 218) from two prospective ICD registries. The cohort consisted of 218 patients (median age: 70 years, male gender: 73%, mean left ventricular ejection fraction [LVEF]: 36 ± 11% at replacement). Median follow‐up after the replacement was 4.2 years during which 64 patients (29%) died and 11 patients (5%) received appropriate ICD shocks. An increase in comorbidities was observed in 77 patients (35%). The 5‐year mortality rate was 41% in patients with ≥2 comorbidities at the time of replacement. A risk score incorporating age, gender, LVEF, atrial fibrillation, anemia, chronic kidney disease, and history of appropriate ICD shocks at time of replacement accurately predicted 5‐year mortality (C‐statistic 0.829). Patients with a risk score of greater than 2.5 had excess mortality at 5‐year postreplacement compared with patients with a risk score less than 1.5 (57% vs. 6%; p <.001). Conclusion: A simple risk score accurately predicts 5‐year mortality after replacement in CRT‐D patients, as patients with a risk score of greater than 2.5 are at high risk of dying despite ICD protection. [ABSTRACT FROM AUTHOR]

Background: Radiofrequency catheter ablation of idiopathic ventricular arrhythmias (VAs) is performed to eliminate symptoms and to prevent or reverse arrhythmia‐induced cardiomyopathy. Preprocedural prediction of the chamber of VA origin is critical for patient counseling, procedure planning, and guidance of invasive mapping. Objective: We aimed to assess the performance of manual expert versus automated 12‐lead electrocardiogram (ECG) analysis in the prediction of VA origin. Methods: Patients with ablation of idiopathic VA and sustained success were included. The VA origin was defined as the site where ablation caused arrhythmia suppression. Standard baseline 12‐lead ECGs with documentation of the VA were analyzed manually in a blinded fashion by three electrophysiologists and three electrophysiology (EP) fellows. In addition, the same standard 12‐lead ECG was analyzed by an automated computer algorithm using a vectorcardiographic approach. Results: Thirty‐eight patients (median age, 47 [interquartile range, 37–58]; 68% female) were enrolled. The VA originated from the right ventricle in 24 (63%) and the left ventricle in 14 (37%) patients. The electrophysiologists and EP fellows identified the VA chamber of origin with a similar accuracy of 73% and 72% (P =.72). The automated algorithm showed a higher accuracy of 89% (P =.03 compared with electrophysiologists and EP fellows). This resulted in a sensitivity of 95% and specificity of 86%. Conclusion: While the manual ECG analysis of the standard 12‐lead ECG by both electrophysiologists and EP fellows correctly identified the chamber of VA origin in around 75% of cases, an automated vectorcardiographic computer algorithm achieved an accuracy of 89% with clinically acceptable diagnostic parameters. [ABSTRACT FROM AUTHOR]