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Background: The HeartLogic algorithm integrates data from implantable defibrillator(ICD) sensors to predict heart failure(HF) decompensation: first(S1) and third(S3) heart sounds, intrathoracic impedance, respiration rate, ratio of respiration rate to tidal volume(RSBI), and night heart rate., Objective: This study assessed the relative changes in ICD sensors at the onset of HeartLogic alerts, their association with patient characteristics, and outcomes., Methods: The study included 568 HF patients carrying ICDs(CRT-D,n=410) across 26 centers, with a median follow-up of 26 months. HeartLogic alerts triggered patient contact and potential treatment., Results: A total of 1200 HeartLogic alerts were recorded in 370 patients. The sensor with the highest change at the alert's onset was S3 in 27% of alerts, followed by S3/S1(25%). Patients with atrial fibrillation(AF) and chronic kidney disease(CKD) at implantation had higher alert prevalence(AF,84% vs. no-AF,58%; CKD,72% vs. no-CKD,59%; p <0.05) and rate (AF,1.51/patient-year vs. no-AF,0.88/patient-year; CKD,1.30/patient-year vs. no-CKD,0.89/patient-year; p<0.05). During follow-up, 247 patients experienced more than one alert; in 85%, the sensor with the highest change varied between successive alerts. Of the 88(7%) alerts associated with HF hospitalization or death, respiration rate or RSBI(11%, p=0.007 vs. S3/S1) and night heart rate(11%, p=0.031 vs. S3/S1) were more commonly the sensors showing the highest change. Clinical events were more common with the first alert(12.6%) than subsequent alerts(5.2%,p <0.001)., Conclusion: HeartLogic alerts are mostly triggered by changes in heart sounds, but clinical events are more linked to respiration rate, RSBI, and night heart rate. Recurrent alerts often involve different sensors, indicating diverse mechanisms of HF progression., (Copyright © 2024. Published by Elsevier Inc.)

Background: Atrial high-rate episodes (AHREs) are frequent in patients with cardiac implantable electronic devices. A decrease in device-detected P-wave amplitude may be an indicator of periods of increased risk of AHRE., Objective: The objective of this study was to assess the association between P-wave amplitude and AHRE incidence., Methods: Remote monitoring data from 2579 patients with no history of atrial fibrillation (23% pacemakers and 77% implantable cardioverter-defibrillators, of which 40% provided cardiac resynchronization therapy) were used to calculate the mean P-wave amplitude during 1 month after implantation. The association with AHRE incidence according to 4 strata of daily burden duration (≥15 minutes, ≥6 hours, ≥24 hours, ≥7 days) was investigated by adjusting the hazard ratio with the CHA 2 DS 2 -VASc score., Results: The adjusted hazard ratio for 1-mV lower mean P-wave amplitude during the first month increased from 1.10 (95% confidence interval [CI], 1.05-1.15; P < .001) to 1.18 (CI, 1.09-1.28; P < .001) with AHRE duration strata from ≥15 minutes to ≥7 days independent of the CHA 2 DS 2 -VASc score. Of 871 patients with AHREs, those with 1-month P-wave amplitude <2.45 mV had an adjusted hazard ratio of 1.51 (CI, 1.19-1.91; P = .001) for progression of AHREs from ≥15 minutes to ≥7 days compared with those with 1-month P-wave amplitude ≥2.45 mV. Device-detected P-wave amplitudes decreased linearly during the 1 year before the first AHRE by 7.3% (CI, 5.1%-9.5%; P < .001 vs patients without AHRE)., Conclusion: Device-detected P-wave amplitudes <2.45 mV were associated with an increased risk of AHRE onset and progression to persistent forms of AHRE independent of the patient's risk profile., Competing Interests: Disclosures Mauro Biffi has held educational activity and participated in speaker’s bureau on behalf of Boston Scientific, Biotronik, and Medtronic. Matteo Ziacchi has held educational activity and participated in speaker’s bureau on behalf of Medtronic. Daniele Giacopelli and Alessio Gargaro are employees of Biotronik Italia S.p.a. The remaining authors have no major conflicts of interest to disclose., (Copyright © 2024 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Beta-blockers are a crucial part of post-myocardial infarction (MI) pharmacological therapy. Recent studies have raised questions about their efficacy in patients without reduced left ventricular ejection fraction (LVEF). This study aims to assess adherence to beta-blockers after discharge for ST-segment elevation myocardial infarction (STEMI) and the impact of adherence on outcomes based on LVEF at discharge. The retrospective registry FAST-STEMI evaluated real-world adherence to main cardiovascular drugs in STEMI patients between 2012 and 2017 by comparing purchased tablets to expected ones at one year through pharmacy registries. Optimal adherence was defined ≥80%. Primary outcomes included all-cause and cardiovascular death, while secondary outcomes were myocardial infarction, major/minor bleeding events, and ischemic stroke The study included 4688 patients discharged on beta-blockers. Mean age was 64 ± 12.3 years, 76% were male, and mean LVEF was 49.2 ± 8.8%. Mean adherence at one year was 87.1%. Optimal adherence was associated with lower all-cause (adjHR 0.62, 95%CI 0.41-0.92, p 0.02) and cardiovascular mortality (adjHR 0.55, 95%CI 0.26-0.98, p 0.043). In LVEF ≤40% patients, optimal adherence was linked to reduced all-cause and cardiovascular mortality but this was not found either in patients with preserved or mildly reduced LVEF. Predictors of cardiovascular mortality included older age, chronic kidney disease, male gender, and atrial fibrillation. Optimal adherence to beta-blocker therapy in all-comers STEMI patients reduced all-cause and cardiovascular mortality at 1 year; once stratified by LVEF, this effect is confirmed only in patients with reduced LVEF (< 40%) at hospital discharge., Competing Interests: Conflicts of interest: none, (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Background: The impact of statin therapy on cardiovascular outcomes after ST-elevation acute myocardial infarction (STEMI) in real- world patients is understudied., Aims: To identify predictors of low adherence and discontinuation to statin therapy within 6 months after STEMI and to estimate their impact on cardiovascular outcomes at one year follow-up., Methods: We evaluated real-world adherence to statin therapy by comparing the number of bought tablets to the expected ones at 1 year follow-up through pharmacy registries. A total of 6043 STEMI patients admitted from 2012 to 2017 were enrolled in the FAST STEMI registry and followed up for 4,7 ± 1,6 years; 304 patients with intraprocedural and intrahospital deaths were excluded. The main outcomes evaluated were all-cause death, cardiovascular death, myocardial infarction, major and minor bleeding events, and ischemic stroke. The compliance cut-off chosen was 80% as mainly reported in literature., Results: From a total of 5744 patients, 418 (7,2%) patients interrupted statin therapy within 6 months after STEMI, whereas 3337 (58,1%) presented >80% adherence to statin therapy. Statin optimal adherence (>80%) resulted as protective factor towards both cardiovascular (0.1% vs 4.6%; AdjHR 0.025, 95%CI 0.008-0.079, p < 0.001) and all-cause mortality (0.3% vs 13.4%; Adj HR 0.032, 95%CI 0.018-0.059, p < 0.001) at 1 year follow-up. Further, a significant reduction of ischemic stroke incidence (1% vs 2.5%, p = 0.001) was seen in the optimal adherent group. Statin discontinuation within 6 months after STEMI showed an increase of both cardiovascular (5% vs 1.7%; AdjHR 2.23; 95%CI 1.37-3.65; p = 0,001) and all-cause mortality (14.8% vs 5.1%, AdjHR 2.32; 95%CI 1.73-3.11; p 〈0,001) at 1 year follow-up. After multivariate analysis age over 75 years old, known ischemic cardiopathy and female gender resulted as predictors of therapy discontinuation. Age over 75 years old, chronic kidney disease, previous atrial fibrillation, vasculopathy, known ischemic cardiopathy were found to be predictors of low statin adherence., Conclusions: n our real-world registry low statin adherence and discontinuation therapy within 6 months after STEMI were independently associated to an increase of cardiovascular and all-cause mortality at 1 year follow-up. Low statin adherence led to higher rates of ischemic stroke., Competing Interests: Declaration of competing interest None., (Copyright © 2024. Published by Elsevier B.V.)

Background: Remote Monitoring (RM) is recognized for its ability to enhance the clinical management of patients with implantable cardiac monitor (ICM). This study aims to provide a comprehensive description of the arrhythmic episodes transmitted by a daily and automatic RM system from a cohort of ICM patients., Methods: The study retrospectively analyzed daily transmissions from consecutive patients who had been implanted with a long-sensing vector ICM (BIOMONITOR III/IIIm) at four sites. All transmitted arrhythmic recordings were evaluated to determine whether they were true positive episodes or false positives (FP)., Results: A total of 14,136 episodes were transmitted from 119 patients (74.8% male, median age 62 years old) during a median follow-up of 371 days. The rate of arrhythmic episodes was 14.2 per patient-year (interquartile range: 1.8-126), with 97 patients (81.5%) experiencing at least one ICM activation. Fifty-five percent of episodes were identified as FP, and 67 patients (56.3%) had at least one inappropriate activation. The FP rate was 1.4 per patient-year (0-40). The best per-episode predictive positive values were observed for bradycardia and atrial fibrillation (0.595 and 0.553, respectively). Notably, the implementation of an algorithm designed to minimize false detections significantly reduced the prevalence of atrial fibrillation FP episodes (17.6% vs. 43.5%, p = 0.008)., Conclusion: Daily and automatic RM appears to be a reliable tool for the comprehensive remote management of ICM patients. However, the number of arrhythmic episodes requiring review is high, and further improvements are needed to reduce FP and facilitate accurate interpretation of transmissions., Competing Interests: Declaration of Competing Interest Paola Napoli and Daniele Giacopelli are employees of BIOTRONIK Italia SPA, an affiliate of BIOTRONIK SE & Co. KG. All the remaining authors have no major conflicts of interest to disclose., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Aims: Subcutaneous implantable cardioverter-defibrillator (S-ICD) therapy is expanding rapidly. However, there are few data on the S-ICD extraction procedure and subsequent patient management. The aim of this analysis was to describe the procedure, management, and outcome of S-ICD extractions in clinical practice., Methods and Results: We enrolled consecutive patients who required complete S-ICD extraction at 66 Italian centres. From 2013 to 2022, 2718 patients undergoing de novo implantation of an S-ICD were enrolled. Of these, 71 required complete S-ICD system extraction (17 owing to infection). The S-ICD system was successfully extracted in all patients, and no complications were reported; the median procedure duration was 40 (25th-75th percentile: 20-55) min. Simple manual traction was sufficient to remove the lead in 59 (84%) patients, in whom lead-dwelling time was shorter [20 (9-32) months vs. 30 (22-41) months; P = 0.032]. Hospitalization time was short in the case of both non-infectious [2 (1-2) days] and infectious indications [3 (1-6) days]. In the case of infection, no patients required post-extraction intravenous antibiotics, the median duration of any antibiotic therapy was 10 (10-14) days, and the re-implantation was performed during the same procedure in 29% of cases. No complications arose over a median of 21 months., Conclusion: The S-ICD extraction was safe and easy to perform, with no complications. Simple traction of the lead was successful in most patients, but specific tools could be needed for systems implanted for a longer time. The peri- and post-procedural management of S-ICD extraction was free from complications and not burdensome for patients and healthcare system., Clinical Trial Registration: URL: http://clinicaltrials.gov/Identifier: NCT02275637., Competing Interests: Conflict of interest: R.R. received speaker fees from Abbot and Boston Scientific. L.O. is a consultant for Boston Scientific. P.F. received speaker fees from Boston Scientific and research or educational grants from Abbott and Boston Scientific. G.L.B. reports speaker fees (small amount) from Boston Scientific, Medtronic, Biotronik, Abbot, Microport, and Zoll. M.L. and S.V. are employees of Boston Scientific. The other authors report no conflicts., (© The Author(s) 2023. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Introduction: Thoracic impedance (TI) drops measured by implantable cardioverter-defibrillators (ICDs) have been reported to correlate with ventricular tachycardia/fibrillation (VT/VF). The aim of our study was to assess the temporal association of decreasing TI trends with VT/VF episodes through a longitudinal analysis of daily remote monitoring data from ICDs and cardiac resynchronization therapy defibrillators (CRT-Ds)., Methods and Results: Retrospective data from 2384 patients were randomized 1:1 into a derivation or validation cohort. The TI decrease rate was defined as the percentage of rolling weeks with a continuously decreasing TI trend. The derivation cohort was used to determine a TI decrease rate threshold for a ≥99% specificity of arrhythmia prediction. The associated risk of VT/VF episodes was estimated in the validation cohort by dividing the available follow-up into 60-day assessment intervals. Analyses were performed separately for 1354 ICD and 1030 CRT-D patients. During a median follow-up of 2.0 years, 727 patients (30.4%) experienced 3298 confirmed VT/VF episodes. In the ICD group, a TI decrease rate of >60% was associated with a higher risk of VT/VF episode in a 60-day assessment interval (stratified hazard ratio, 1.42; 95% confidence interval (CI), 1.05-1.92; p = .023). The TI decrease preceded (40.8%) or followed (59.2%) the VT/VF episodes. In the CRT-D group, no association between TI decrease and VT/VF episodes was observed (p = .84)., Conclusion: In our longitudinal analysis, TI decrease was associated with VT/VF episodes only in ICD patients. Preventive interventions may be difficult since episodes can occur before or after TI decrease., (© 2023 Wiley Periodicals LLC.)

Background: Elevated resting heart rate is a risk factor for cardiovascular events., Objective: The purpose of this study was to investigate the clinical significance of nocturnal heart rate (nHR) and 24-hour mean heart rate (24h-HR) obtained by continuous remote monitoring (RM) of implantable devices., Methods: We analyzed daily-sampled trends of nHR, 24h-HR, and physical activity in patients on β-blocker therapy for chronic heart failure and with implantable cardioverter-defibrillators or cardiac resynchronization therapy defibrillators (CRT-Ds). Patients were grouped by average nHR and 24h-HR quartile during follow-up to estimate the respective incidence of nonarrhythmic death and device-treated ventricular tachycardia/fibrillation (VT/VF)., Results: The study cohort included 1330 patients (median age 69 years [interquartile range 61-77 years]; 41% [n = 550] with CRT-D; median follow-up 25 months [interquartile range 13-42 months]). Compared with patients in the lowest nHR quartile (≤57 beats/min) group, patients in the highest quartile group (>65 beats/min) had an increased risk of nonarrhythmic death (adjusted hazard ratio [AHR] 2.25; 95% confidence interval [CI] 1.13-4.50; P = .021) and VT/VF (AHR 1.98; 95% CI 1.40-2.79; P < .001) and were characterized by the lowest level of physical activity (P ≤ .0004 vs every other nHR quartiles). The highest 24h-HR quartile group (>75 beats/min) showed an increased risk of VT/VF (AHR 2.13; 95% CI 1.52-2.99; P < .001) and a weaker though significant association with nonarrhythmic mortality (AHR 1.80; 95% CI 1.00-3.22; P = .05) as compared with the lowest 24h-HR quartile group (≤65 beats/min)., Conclusion: In remotely monitored patients with implantable cardioverter-defibrillator/CRT-D on β-blocker therapy for heart failure, elevated heart rates (nHR >65 beats/min and 24h-HR >75 beats/min) were associated with increased mortality and VT/VF risk. nHR showed a stronger association than 24h-HR with worst prognosis and lowest physical activity., (Copyright © 2022 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Background: Causes of sex differences in incidence of sustained ventricular arrhythmias (SVAs) are poorly understood., Objectives: This study aims to investigate sex-specific risk of SVAs and device therapies by balancing sex groups in relation to several baseline characteristics with the propensity score (PS)., Methods: We used a large remote monitoring dataset from implantable cardioverter-defibrillators (ICDs) and cardiac resynchronization therapy defibrillators (CRT-Ds). Study endpoints were time to the first appropriate SVA, time to the first device therapy for SVA, and time to the first ICD shock. Results were compared between females and a PS-matched male subgroup., Results: In a cohort of 2,532 patients with an ICD or CRT-D (median age, 70 years), 488 patients (19.3%) were women. After selecting 488 men PS-matched for 19 variables relative to baseline demographics, implant indications, principal comorbidities, and concomitant therapy, yet the SVA rate at the 2.1-year median follow-up was significantly lower in women than in man (adjusted HR: 0.65; 95% CI: 0.51-0.81; P < 0.001). Women also showed a reduced risk of any device therapy (HR: 0.59; 95% CI: 0.45-0.76; P < 0.001) and shocks (HR: 0.66; 95% CI: 0.47-0.94; P = 0.021). Differences in sex-specific SVA risk profile were not confirmed in CRT-D patients (HR: 0.78; 95% CI: 0.55-1.09; P = 0.14) nor in those with an ejection fraction <30% (HR: 0.80; 95% CI: 0.52-1.23; P = 0.31)., Conclusions: After matching demographics, indications, principal comorbidities, and concomitant therapy, women still exhibited a lower SVA risk profile than men, except in the subgroups of CRT-D or/and ejection fraction <30%., Competing Interests: Funding Support and Author Disclosures Manuscript editing was partially supported by BIOTRONIK Italia S.p.A. (V.le delle Industrie 11, 20055, Vimodrone [MI], Italy), which also provided assistance in statistical analysis but had no role in data collection and interpretation. Mr Giacopelli and Mr Gargaro are employees of BIOTRONIK Italia. All other authors have reported that they have relationships relevant to the contents of this paper to disclose., (Copyright © 2022 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Purpose: The purpose of this study was to assess the available mortality risk stratification models for implantable cardioverter defibrillator (ICD) and cardiac resynchronization therapy defibrillator (CRT-D) patients., Methods: We conducted a review of mortality risk stratification models and tested their ability to improve prediction of 1-year survival after implant in a database of patients who received a remotely controlled ICD/CRT-D device during routine care and included in the independent Home Monitoring Expert Alliance registry., Results: We identified ten predicting models published in peer-reviewed journals between 2000 and 2021 (Parkash, PACE, MADIT, aCCI, CHA2DS2-VASc quartiles, CIDS, FADES, Sjoblom, AAACC, and MADIT-ICD non-arrhythmic mortality score) that could be tested in our database as based on common demographic, clinical, echocardiographic, electrocardiographic, and laboratory variables. Our cohort included 1,911 patients with left ventricular dysfunction (median age 71, 18.3% female) from sites not using any risk stratification score for systematic patient screening. Patients received an ICD (53.8%) or CRT-D (46.2%) between 2011 and 2017, after standard physician evaluation. There were 56 deaths within 1-year post-implant, with an all-cause mortality rate of 2.9% (95% confidence interval [CI], 2.3-3.8%). Four predicting models (Parkash, MADIT, AAACC, and MADIT-ICD non-arrhythmic mortality score) were significantly associated with increased risk of 1-year mortality with hazard ratios ranging from 3.75 (CI, 1.31-10.7) to 6.53 (CI 1.52-28.0, p ≤ 0.014 for all four). Positive predictive values of 1-year mortality were below 25% for all models., Conclusion: In our analysis, the models we tested conferred modest incremental predicting power to ordinary screening methods., (© 2021. Springer Science+Business Media, LLC, part of Springer Nature.)

Stratifying prognosis following coronary bifurcation percutaneous coronary intervention (PCI) is an unmet clinical need that may be fulfilled through the adoption of machine learning (ML) algorithms to refine outcome predictions. We sought to develop an ML-based risk stratification model built on clinical, anatomical, and procedural features to predict all-cause mortality following contemporary bifurcation PCI. Multiple ML models to predict all-cause mortality were tested on a cohort of 2393 patients (training, n = 1795; internal validation, n = 598) undergoing bifurcation PCI with contemporary stents from the real-world RAIN registry. Twenty-five commonly available patient-/lesion-related features were selected to train ML models. The best model was validated in an external cohort of 1701 patients undergoing bifurcation PCI from the DUTCH PEERS and BIO-RESORT trial cohorts. At ROC curves, the AUC for the prediction of 2-year mortality was 0.79 (0.74-0.83) in the overall population, 0.74 (0.62-0.85) at internal validation and 0.71 (0.62-0.79) at external validation. Performance at risk ranking analysis, k-center cross-validation, and continual learning confirmed the generalizability of the models, also available as an online interface. The RAIN-ML prediction model represents the first tool combining clinical, anatomical, and procedural features to predict all-cause mortality among patients undergoing contemporary bifurcation PCI with reliable performance.

The association of left ventricular ejection fraction (LVEF) with procedural and long-term outcomes after state-of-the-art percutaneous coronary intervention (PCI) of bifurcation lesions remains unsettled. A total of 5,333 patients who underwent contemporary coronary bifurcation PCI were included in the intercontinental retrospective combined insights from the unified RAIN (veRy thin stents for patients with left mAIn or bifurcatioN in real life) and COBIS (COronary BIfurcation Stenting) III bifurcation registries. Of 5,003 patients (93.8%) with known baseline LVEF, 244 (4.9%) had LVEF <40% (bifurcation with reduced ejection fraction [BIFrEF] group), 430 (8.6%) had LVEF 40% to 49% (bifurcation with mildly reduced ejection fraction [BIFmEF] group) and 4,329 (86.5%) had ejection fraction (EF) ≥50% (bifurcation with preserved ejection fraction [BIFpEF] group). The primary end point was the Kaplan-Meier estimate of major adverse cardiac events (MACEs) (a composite of all-cause death, myocardial infarction, and target vessel revascularization). Patients with BIFrEF had a more complex clinical profile and coronary anatomy. No difference in procedural (30 days) MACE was observed across EF categories, also after adjustment for in-study outcome predictors (BIFrEF vs BIFmEF: adjusted hazard ratio [adj-HR] 1.39, 95% confidence interval [CI] 0.37 to 5.21, p = 0.626; BIFrEF vs BIFpEF: adj-HR 1.11, 95% CI 0.25 to 2.87, p = 0.883; BIFmEF vs BIFpEF: adj-HR 0.81, 95% CI 0.29 to 2.27, p = 0.683). BIFrEF was independently associated with long-term MACE (median follow-up 21 months, interquartile range 10 to 21 months) than both BIFmEF (adj-HR 2.20, 95% CI 1.41 to 3.41, p <0.001) and BIFpEF (adj-HR 1.91, 95% CI 1.41 to 2.60, p <0.001) groups, although no difference was observed between BIFmEF and BIFpEF groups (adj-HR 0.87, 95% CI 0.61 to 1.24, p = 0.449). In conclusion, in patients who underwent PCI of a coronary bifurcation lesion according to contemporary clinical practice, reduced LVEF (<40%), although a strong predictor of long-term MACEs, does not affect procedural outcomes., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Aims: The utilization of remote monitoring platforms was recommended amidst the COVID-19 pandemic. The HeartLogic index combines multiple implantable cardioverter defibrillator (ICD) sensors and has proved to be a predictor of impending heart failure (HF) decompensation. We examined how multiple ICD sensors behave in the periods of anticipated restrictions pertaining to physical activity., Methods: The HeartLogic feature was active in 349 ICD and cardiac resynchronization therapy ICD patients at 20 Italian centers. The period from 1 January to 19 July 2020, was divided into three phases: pre-lockdown (weeks 1-11), lockdown (weeks 12-20), post-lockdown (weeks 21-29)., Results: Immediately after the implementation of stay-at-home orders (week 12), we observed a significant drop in median activity level whereas there was no difference in the other contributing parameters. The median composite HeartLogic index increased at the end of the Lockdown. The weekly rate of alerts was significantly higher during the lockdown (1.56 alerts/week/100 pts, 95%CI: 1.15-2.06; IRR = 1.71, p = 0.014) and post-lockdown (1.37 alerts/week/100 pts, 95%CI: 0.99-1.84; IRR = 1.50, p = 0.072) than that reported in pre-lockdown (0.91 alerts/week/100 pts, 95%CI: 0.64-1.27). However, the median duration of alert state and the maximum index value did not change among phases, as well as the proportion of alerts followed by clinical actions at the centers and the proportion of alerts fully managed remotely., Conclusions: During the lockdown, the system detected a significant drop in the median activity level and generated a higher rate of alerts suggestive of worsening of the HF status.

Aims: There are conflicting data on the benefit of cardiac resynchronization therapy (CRT) in heart failure (HF) patients with permanent atrial fibrillation (AF). We aimed to compare patient outcomes according to the presence or absence of permanent AF at device implantation., Methods and Results: We retrospectively analysed remote monitoring data from 1141 CRT defibrillators. Propensity score with inverse-probability weighting method was used to balance AF and sinus rhythm (SR) groups. Analysis endpoints included total mortality, appropriate defibrillation shocks, and CRT percentage. There were 229 patients (20.1%) in the AF group and 912 patients (79.9%) in the SR group. Compared with SR patients, AF patients were older (median age, 77 vs. 72 years, P < 0.001), more frequently male (82.5% vs. 75.5%, P = 0.02), and had higher heart rate (75.7 vs. 71.0 b.p.m., P < 0.001). Of the 229 AF patients, 162 (70.7%) received suboptimal CRT (<98%) and 67 (29.3%) had adequate CRT (≥98%). During a median follow-up of 24 months, total mortality did not differ between AF and SR groups (propensity-score-weighted hazard ratio, HR 1.32 [95% confidence interval, 0.82-2.15], P = 0.25). The risk of appropriate shocks was significantly higher in the AF group with <98% CRT than in the SR group (weighted-HR, 1.99 [1.21-3.26], P = 0.006) and was similar in the AF group with ≥98% CRT versus the SR group (1.29 [0.66-2.53], P = 0.45). During follow-up, sinus rhythm was recovered in 23 patients in the AF group (10%) after a median time of 106 (42-256) days. The rate of sinus rhythm recovery in the AF group was 4.5 (95% CI, 2.8-6.7) per 100 patient-years; the rate of permanent AF occurrence in the SR group was 2.5 (95% CI, 1.9-3.3) per 100 patient-years., Conclusions: Although mortality was similar across patient groups, patients with permanent AF and suboptimal CRT had twofold higher risk of appropriate shocks than SR patients or AF patients with CRT ≥ 98%., (© 2021 The Authors. ESC Heart Failure published by John Wiley & Sons Ltd on behalf of European Society of Cardiology.)