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Background: In the event of infection, erosion, or failure, fibrosis of a defibrillation lead can make extraction difficult. In the ENDOTAK RELIANCE G defibrillation lead, coils are covered with expanded polytetrafluoroethylene (ePTFE) to prevent tissue ingrowth. Objective: The objective of the REFLEx Study was to evaluate if RELIANCE G defibrillation leads with ePTFE-covered coils are as good as comparative defibrillation leads with respect to electrical performance and termination of spontaneous tachyarrhythmias. Methods: Patients were randomized to type of defibrillation lead-Guidant RELIANCE G lead or a non-ePTFE-covered lead of choice. Electrical performance success was defined as meeting all minimum standards in the respective manufacturer's manual for amplitude, threshold, and impedance. A noninferiority margin of 5% was prespecified. Results: Electrical performance success at 12 months was 93.0% (280/301) for RELIANCE G and 94.5% (291/308) for comparative leads. The performance success rate for RELIANCE G did not differ significantly from study comparative (P = 0.04, noninferiority). For spontaneous episodes, first shock conversion success rate was 90% for RELIANCE G and 95% for study comparative (P = 0.89, noninferiority). Implant conversion testing was successful in 96.7% (524/542) of RELIANCE G patients and 94.3% (512/543) of comparative patients (chi-square P-value = 0.0784). About 55% (609/1115) of patients completed follow-up through month 12. Conclusion: Data from the REFLEx study indicate that ePTFE-covered leads are not inferior to comparative leads with respect to electrical performance and implant conversion testing. We cannot conclude that the first shock conversion efficacy of ePTFE covered leads was statistically noninferior to comparative leads. [ABSTRACT FROM AUTHOR]

Objectives: The purpose of this study was to characterize the relationship between changes in body mass index (BMI) and incident atrial fibrillation (AF) in a large cohort of women.Background: Obesity and AF are increasing public health problems. The importance of dynamic obesity-associated AF risk is uncertain, and mediators are not well characterized.Methods: Cases of AF were confirmed by medical record review in 34,309 participants in the Women's Health Study. Baseline and updated measures of BMI were obtained from periodic questionnaires.Results: During 12.9 +/- 1.9 years of follow-up, 834 AF events were confirmed. BMI was linearly associated with AF risk, with a 4.7% (95% confidence interval [CI]: 3.4 to 6.1, p < 0.0001) increase in risk with each kilogram per square meter. Adjustment for inflammatory markers minimally attenuated this risk. When updated measures of BMI were used to estimate dynamic risk, overweight (hazard ratio [HR]: 1.22; 95% CI: 1.02 to 1.45, p = 0.03), and obesity (HR: 1.65; 95% CI: 1.36 to 2.00; p < 0.0001) were associated with adjusted short-term increases in AF risk. Participants becoming obese during the first 60 months had a 41% adjusted increase in risk of the development of AF (p = 0.02) compared with those maintaining BMI <30 kg/m(2). The prevalence of overweight and obesity increased over time. The adjusted proportion of incident AF attributable to short-term elevations in BMI was substantial (18.3%).Conclusions: In this population of apparently healthy women, BMI was associated with short- and long-term increases in AF risk, accounting for a large proportion of incident AF independent of traditional risk factors. A strategy of weight control may reduce the increasing incidence of AF. (Women's Health Study [WHS]: A Randomized Trial of Low-Dose Aspirin and Vitamin E in the Primary Prevention of Cardiovascular Disease and Cancer; NCT00000479). [ABSTRACT FROM AUTHOR]

Background: Sudden death accounts for approximately 25% of deaths among maintenance hemodialysis patients, occurring more frequently on hemodialysis days. Higher dialysate bicarbonate (DBIC) may predispose to alkalemia and arrhythmogenesis., Methods: We conducted a 12-month analysis of session-level data from 66 patients with implantable loop recorders. We fit logistic regression and negative binomial mixed-effects regression models to assess the association of DBIC with clinically significant arrhythmia (ventricular tachycardia ≥115 beats per minute [BPM] for at least 30 seconds, bradycardia ≤40 BPM for at least 6 seconds, or asystole for at least 3 seconds) and reviewer confirmed arrhythmia (RCA—implantable loop recorder-identified or patient-marked event for which a manual review of the stored electrocardiogram tracing confirmed the presence of atrial fibrillation, supraventricular tachycardia, sinus tachycardia with rate >130 BPM, ventricular tachycardia, asystole, or bradycardia). Models adjusted for age, sex, race, hemodialysis vintage, vascular access, and prehemodialysis serum bicarbonate and additionally for serum and dialysate potassium levels., Results: The mean age was 56±12 years, 70% were male, 53% were Black, and 35% were Asian. Fewer RCA episodes were associated with DBIC >35 than 35 mEq/L (incidence rate ratio 0.45 [0.27 to 0.75] and adjusted incident rate ratio 0.54 [0.30 to 0.97]), but the association was not significant when adjusting for serum and dialysate potassium levels (adjusted incident rate ratio, 0.60 [0.32 to 1.11]). Otherwise, no associations between DBIC and arrhythmia were identified., Conclusions: We observed a lower frequency of RCA with higher DBIC, compared with DBIC of 35 mEql/L, contrary to our original hypothesis, but this association was attenuated in fully adjusted models. Validation of these findings in larger studies is required, with a further need for interventional studies to explore the optimal DBIC concentration., (Copyright © 2024 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Society of Nephrology)

Introduction: High-frequency low-tidal-volume (HFLTV) ventilation during radiofrequency catheter ablation (RFCA) for paroxysmal atrial fibrillation (PAF) has been shown to be superior to standard ventilation (SV) in terms of procedural efficiency, acute and long-term clinical outcomes. Our study aimed to compare ablation lesions characteristics utilizing HFLTV ventilation versus SV during RFCA of PAF., Methods: A retrospective analysis was conducted on patients who underwent pulmonary vein isolation (PVI) for PAF between August 2022 and March 2023, using high-power short-duration ablation. Thirty-five patients underwent RFCA with HFLTV ventilation and were matched with another cohort of 35 patients who underwent RFCA with SV. Parameters including ablation duration, contact force (CF), impedance drop, and ablation index were extracted from the CARTONET database for each ablation lesion., Results: A total of 70 patients were included (HFLTV = 35/2484 lesions, SV = 35/2830 lesions) in the analysis. There were no differences in baseline characteristics between the groups. While targeting the same ablation index, the HFLTV ventilation group demonstrated shorter average ablation duration per lesion (12.3 ± 5.0 vs. 15.4 ± 8.4 s, p < .001), higher average CF (17.0 ± 8.5 vs. 10.5 ± 4.6 g, p < .001), and greater impedance reduction (9.5 ± 4.6 vs. 7.7 ± 4.1 ohms, p < .001). HFLTV ventilation group also demonstrated shorter total procedural time (61.3 ± 25.5 vs. 90.8 ± 22.8 min, p < .001), ablation time (40.5 ± 18.6 vs. 65.8 ± 22.5 min, p < .001), and RF time (15.3 ± 4.8 vs. 22.9 ± 9.7 min, p < .001)., Conclusion: HFLTV ventilation during PVI for PAF was associated with improved ablation lesion parameters and procedural efficiency compared to SV., (© 2024 Wiley Periodicals LLC.)

Background: Left bundle branch area pacing (LBBAP) has emerged as a physiological alternative pacing strategy to biventricular pacing (BIVP) in cardiac resynchronization therapy (CRT). We aimed to assess the impact of LBBAP vs. BIVP on all-cause mortality and heart failure (HF)-related hospitalization in patients undergoing CRT., Methods: Studies comparing LBBAP and BIVP for CRT in patients with HF with reduced left ventricular ejection fraction (LVEF) were included. The coprimary outcomes were all-cause mortality and HF-related hospitalization. Secondary outcomes included procedural and fluoroscopy time, change in QRS duration, and change in LVEF., Results: Thirteen studies (12 observational and 1 RCT, n = 3239; LBBAP = 1338 and BIVP = 1901) with a mean follow-up duration of 25.8 months were included. Compared to BIVP, LBBAP was associated with a significant absolute risk reduction of 3.2% in all-cause mortality (9.3% vs 12.5%, RR 0.7, 95% CI 0.57-0.86, p < 0.001) and an 8.2% reduction in HF-related hospitalization (11.3% vs 19.5%, RR 0.6, 95% CI 0.5-0.71, p < 0.00001). LBBAP also resulted in reductions in procedural time (mean weighted difference- 23.2 min, 95% CI - 42.9 to - 3.6, p = 0.02) and fluoroscopy time (- 8.6 min, 95% CI - 12.5 to - 4.7, p < 0.001) as well as a significant reduction in QRS duration (mean weighted difference:- 25.3 ms, 95% CI - 30.9 to - 19.8, p < 0.00001) and a greater improvement in LVEF of 5.1% (95% CI 4.4-5.8, p < 0.001) compared to BIVP in the studies that reported these outcomes., Conclusion: In this meta-analysis, LBBAP was associated with a significant reduction in all-cause mortality as well as HF-related hospitalization when compared to BIVP. Additional data from large RCTs is warranted to corroborate these promising findings., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background: Women respond more favorably to biventricular pacing (BIVP) than men. Sex differences in atrioventricular and interventricular conduction have been described in BIVP studies. Left bundle branch area pacing (LBBAP) offers advantages due to direct capture of the conduction system. We hypothesized that men could respond better to LBBAP than BIVP., Objectives: This study aims to describe the sex differences in response to LBBAP vs BIVP as the initial cardiac resynchronization therapy (CRT)., Methods: In this multicenter prospective registry, we included patients with left ventricular ejection fraction ≤35% and left bundle branch block or a left ventricular ejection fraction ≤40% with an expected right ventricular pacing exceeding 40% undergoing initial CRT with LBBAP or BIVP. The composite primary outcome was heart failure-related hospitalization and all-cause mortality. The primary safety outcome included all procedure-related complications., Results: There was no significant difference in the primary outcome when comparing men and women receiving LBBAP (P = 0.46), whereas the primary outcome was less frequent in women in the BIVP group than men treated with BIVP (P = 0.03). The primary outcome occurred less frequently in men undergoing LBBAP (29.9%) compared to those treated with BIVP (46.5%) (P = 0.004). In women, the incidence of the primary endpoint was 24.14% in the LBBAP group and 36.2% in the BIVP group; however, this difference was not statistically significant (P = 0.23). Complication rates remained consistent across all groups., Conclusions: Men and women undergoing LBBAP for CRT had similar clinical outcomes. Men undergoing LBBAP showed a lower risk of heart failure-related hospitalizations and all-cause mortality compared to men undergoing BIVP, whereas there was no difference between LBBAP and BIVP in women., Competing Interests: Funding Support and Author Disclosures Dr Diaz has received speaker honoraria and has been a proctor for Medtronic for conduction system pacing. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2024 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Rationale & Objective: The incidence of arrhythmia varies by time of day. How this affects individuals on maintenance dialysis is uncertain. Our objective was to quantify the relationship of arrhythmia with the time of day and timing of dialysis., Study Design: Secondary analysis of the Monitoring in Dialysis study, a multicenter prospective cohort study., Settings & Participants: Loop recorders were implanted for continuous cardiac monitoring in 66 participants on maintenance dialysis with a follow up of 6 months., Exposure: Time of day based on 6-hour intervals., Outcomes: Event rates of clinically significant arrhythmia., Analytical Approach: Negative binomial mixed effects regression models for repeated measures were used to evaluate data from the Monitoring in Dialysis study for differences in diurnal patterns of clinically significant arrhythmia among those with end-stage kidney disease with heart failure and end-stage kidney disease alone. We additionally analyzed rates according to presence of heart failure, time of dialysis shift, and dialysis versus nondialysis day., Results: Rates of clinically significant arrhythmia peaked between 12:00 AM and 5:59 AM and were more than 1.5-fold as frequent during this interval than the rest of the day. In contrast, variations in atrial fibrillation peaked between 6:00 AM and 11:59 AM, but variations across the day were qualitatively small. Clinically significant arrhythmia occurred at numerically higher rate in individuals with end-stage kidney disease and heart failure (5.9 events/mo; 95% CI, 1.3-26.8) than those without heart failure (4.0 events/mo; 95% CI, 0.9-17.9). Although differences in overall rate were not significant, their periodicity was significantly different ( P  < 0.001), with a peak between 12:00 AM and 6:00 AM with kidney failure alone and between 6:00 AM and 11:59 AM in those with heart failure. Although the overall clinically significant arrhythmia rate was similar in morning compared with evening dialysis shifts ( P  = 0.43), their periodicity differed with a peak between 12:00 AM and 5:59 AM in those with AM dialysis and a later peak between 6:00 AM and 11:59 AM in those with PM shifts., Limitations: Post hoc analysis, unable to account for unmeasured confounders., Conclusion: Clinically significant arrhythmias showed strong diurnal patterns with a maximal peak between 12:00 AM and 5:59 AM and noon. Although overall arrhythmia rates were similar, the peak rate occurred overnight in individuals without heart failure and during the morning in individuals with heart failure. Further exploration of the influence of circadian rhythm on arrhythmia in the setting of hemodialysis is needed., (© 2024 The Authors.)

Background: Left bundle branch pacing (LBBP) and left ventricular septal pacing (LVSP) are considered to be acceptable as LBBAP strategies. Differences in clinical outcomes between LBBP and LVSP are yet to be determined., Objectives: The purpose of this study was to compare the outcomes of LBBP vs LVSP vs BIVP for CRT., Methods: In this prospective multicenter observational study, LBBP was compared with LVSP and BIVP in patients undergoing CRT. The primary composite outcome was freedom from heart failure (HF)-related hospitalization and all-cause mortality. Secondary outcomes included individual components of the primary outcome, postprocedural NYHA functional class, and electrocardiographic and echocardiographic parameters., Results: A total of 415 patients were included (LBBP: n = 141; LVSP: n = 31; BIVP: n = 243), with a median follow-up of 399 days (Q1-Q3: 249.5-554.8 days). Freedom from the primary composite outcomes was 76.6% in the LBBP group and 48.4% in the LVSP group (HR: 1.37; 95% CI: 1.143-1.649; P = 0.001), driven by a 31.4% absolute increase in freedom from HF-related hospitalizations (83% vs 51.6%; HR: 3.55; 95% CI: 1.856-6.791; P < 0.001) without differences in all-cause mortality. LBBP was also associated with a higher freedom from the primary composite outcome compared with BIVP (HR: 1.43; 95% CI: 1.175-1.730; P < 0.001), with no difference between LVSP and BIVP., Conclusions: In patients undergoing CRT, LBBP was associated with improved outcomes compared with LVSP and BIVP, while outcomes between BIVP and LVSP are similar., Competing Interests: Funding Support and Author Disclosures Dr Diaz has received speaker honoraria from and is a proctor for Medtronic for LBBAP. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2024 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: Left bundle branch area pacing (LBBAP) for cardiac resynchronization therapy (CRT) is an alternative to biventricular pacing (BiVp)., Objectives: The purpose of this study was to compare the outcomes between LBBAP and BiVp as an initial implant strategy for CRT., Methods: In this prospective multicenter, observational, nonrandomized study, first-time CRT implant recipients with LBBAP or BiVp were included. The primary efficacy outcome was a composite of heart failure (HF)-related hospitalization and all-cause mortality. The primary safety outcomes were acute and long-term complications. Secondary outcomes included postprocedural New York Heart Association functional class and electrocardiographic and echocardiographic parameters., Results: A total of 371 patients (median follow-up of 340 days [IQR: 206-477 days]) were included. The primary efficacy outcome occurred in 24.2% in the LBBAP vs 42.4% in the BiVp (HR: 0.621 [95% CI: 0.415-0.93]; P = 0.021) group, driven by a reduction in HF-related hospitalizations (22.6% vs 39.5%; HR: 0.607 [95% CI: 0.397-0.927]; P = 0.021) without significant difference in all-cause mortality (5.5% vs 11.9%; P = 0.19) or differences in long-term complications (LBBAP: 9.4% vs BiVp: 15.2%; P = 0.146). LBBAP resulted in shorter procedural (95 minutes [IQR: 65-120 minutes] vs 129 minutes [IQR: 103-162 minutes]; P < 0.001) and fluoroscopy times (12 minutes [IQR: 7.4-21.1 minutes] vs 21.7 minutes [IQR: 14.3-30 minutes]; P < 0.001), shorter QRS duration (123.7 ± 18 milliseconds vs 149.3 ± 29.1 milliseconds; P < 0.001), and higher postprocedural left ventricular ejection fraction (34.1% ± 12.5% vs 31.4% ± 10.8%; P = 0.041)., Conclusions: LBBAP as an initial CRT strategy resulted in a lower risk of HF-related hospitalizations compared to BiVp. A reduction in procedural and fluoroscopy times, shorter paced QRS duration, and improvements in left ventricular ejection fraction compared with BiVp were observed., Competing Interests: Funding Support and Author Disclosures Dr Diaz has received speaker honoraria and is a proctor for Medtronic for conduction system pacing. 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.)

Background: Epicardial access (EA) has emerged as an increasingly important approach for the treatment of ventricular arrhythmias and to perform other interventional cardiology procedures. EA is frequently underutilized because the current approach is challenging and carries a high risk of life-threatening complications., Objective: The purpose of this study was to determine the efficacy and safety of the SAFER (Sustained Apnea for Epicardial Access With Right Ventriculography) epicardial approach., Methods: Consecutive patients who underwent EA with the SAFER technique were included in this multicenter study. The primary efficacy outcome was the successful achievement of EA. The primary safety outcomes included right ventricular (RV) perforation, major hemorrhagic pericardial effusion (HPE), and bleeding requiring surgical intervention. Secondary outcomes included procedural characteristics and any complications. Our results were compared with those from previous studies describing other EA techniques to assess differences in outcomes., Results: A total of 105 patients undergoing EA with the SAFER approach from June 2021 to February 2023 were included. EA was used for ventricular tachycardia ablation in 98 patients (93.4%), left atrial appendage closure in 6 patients (5.7%), and phrenic nerve displacement in 1 patient (0.9%). EA was successful in all subjects (100%). The median time to EA was 7 minutes (IQR: 5-14 minutes). No cases of RV perforation, HPE, or need of surgical intervention were observed in this cohort. Comparing our results with previous studies about EA, the SAFER epicardial approach resulted in a significant reduction in major pericardial bleeding., Conclusions: The SAFER epicardial approach is a simple, efficient, effective, and low-cost technique easily reproducible across multiple centers. It is associated with lower complication rates than previously reported techniques for EA., Competing Interests: Funding Support and Author Disclosures All 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.)

Background: Bradycardia and asystole events are common among patients treated with maintenance hemodialysis. However, triggers of these events in patients on maintenance hemodialysis (HD), particularly during the long interdialytic period when these events cluster, are uncertain., Methods: The Monitoring in Dialysis Study (MiD) enrolled 66 patients on maintenance HD who were implanted with loop recorders and followed for 6 months. We analyzed associations of predialysis laboratory values with clinically significant bradyarrhythmia or asystole (CSBA) during the 12 hours before an HD session. Associations with CSBA were analyzed with mixed-effect models. Adjusted negative binomial mixed-effect regression was used to estimate incidence rate ratios (IRR) for CSBA. We additionally evaluated associations of CSBA at any time during follow-up with time-averaged dialytic and laboratory parameters and associations of peridialytic parameters with occurrence of CSBA from the start of one HD session to the beginning of the next., Results: There were 551 CSBA that occurred in the last 12 hours of the interdialytic interval preceding 100 HD sessions in 12% of patients and 1475 CSBA events in 23% of patients overall. We did not identify significant associations between dialytic parameters or serum electrolytes and CSBA in the last 12 hours of the interdialytic interval in adjusted analyses. Median time-averaged ultrafiltration rate was significantly higher in individuals without CSBA (9.8 versus 8, P =0.04). Use of dialysate sodium concentrations ≤135 (versus 140) mEq/L was associated with a reduced risk of CSBA from the start of one session to the beginning of next., Conclusions: Although a few factors had modest associations with CSBA in some analyses, we did not identify any robust associations of modifiable parameters with CSBA in the MiD Study. Further investigation is needed to understand the high rates of arrhythmia in the hemodialysis population., Competing Interests: N. Bansal reports an advisory or leadership role for Kidney360 (associate editor). D.M. Charytan reports consultancy for Amgen, Allena Pharmaceuticals (DSMB), AstraZeneca, CSL Behring, Eli Lilly/Boehringer Ingelheim, Fresenius, Gilead, GSK, Janssen (steering committee), Medtronic, Merck, Novo Nordisk, PLC medical (clinical events committee), Renalytix, and Zogenix; research funding from Amgen, Bioporto (clinical trial support), Gilead, Medtronic (clinical trial support), and NovoNordisk; an advisory or leadership role for CJASN; and other interests or relationships as an expert witness (fees related to proton pump inhibitors). A.I. Costea reports consultancy for Biosense Webster and Biotronik; research funding from Biosense Webster and Biotronik; honoraria from Biosense Webster and Biotronik; an advisory or leadership role for the Journal of Cardiovascular Electrophysiology; and participation in a speakers’ bureau for Biosense Webster and Biotronik. S. Pokhariyal reports ownership interest in VitusCare Medlife PVT Ltd. P. Roy-Chaudhury reports consultancy for Akebia, Bayer, BD-Bard, Cormedix, Humacyte, InRegen, Medtronic/Covidien, Reata, Vifor-Relypsa, and WL Gore; ownership interest in Inovasc LLC (chief scientific officer and founder); research funding in the form of NIH small business grants as the MPI or site PI with Adgero, Cylerus, Eko, and Inovasc; honoraria from Akebia, Bayer, BD-Bard, Chugai Pharmaceuticals, Cormedix, Humacyte, InRegen, Medtronic/Covidien, Reata, Vifor-Relypsa, and WL Gore; an advisory or leadership role for Akebia, ASN, Bayer, BD-Bard, Cardiorenal Society, Cormedix, Humacyte, InRegen, Medtronic/Covidien, Reata, the Vascular Access Society of the Americas, Vifor-Relypsa, and WL Gore; being on the editorial board for the Journal of Vascular Access; and other interests or relationships with Elucid Bio, Outset Medical, the University of Arizona with Kidney Research Institute, Seattle (research contract), and Vasbio. J.A. Tumlin reports consultancy for Abbott Pharmaceuticals, Abbvie Pharmaceuticals, Achillion Pharmaceuticals, Alexion Pharmaceuticals, AstraZeneca Pharmaceuticals, Epizon Pharmaceuticals, Gilead Aurinia Pharmaceuticals, Johnson& Johnson, LaJolla Pharmaceuticals, Liliy Pharmaceuticals, Mallinckrodt Pharmaceuticals, NephroNet Clinical Trials Consortium, Relypsa Pharmaceuticals, and ZS Pharmaceuticals; research funding from Abbvie Pharmaceuticals, Achillion Pharmaceuticals, Akebia Pharmaceuticals, AstraZeneca, Epizon Pharmaceuticals, Gilead Pharmaceuticals, Johnson& Johnson, LaJolla Pharmaceuticals, Mallinckrodt Pharmaceuticals, NephroNet Clinical Trials Consortium, Relypsa Pharmaceuticals, Vinterra Pharmaceuticals, and ZS Pharmaceuticals; honoraria from Alexion Pharmaceuticals, AstraZeneca Pharmaceuticals, Aurinia Pharmaceuticals, Bayer Pharmaceuticals, Genentech, Genzyme Corp., and Mallinckrodt Pharmaceuticals; patents or royalties from HIBAR Microsciences LLC; an advisory or leadership role for Achillion Pharmaceuticals, Alexion Pharmaceuticals, Bayer Corp., Bayer Pharmaceuticals, Chemocentryx, Epizon Pharmaceuticals, Gilead Pharmaceuticals, KBP Pharmaceuticals, and Relypsa Pharmaceuticals; participation in a speakers’ bureau for Alexion Pharmaceuticals, AstraZeneca Pharmaceuticals, Aurinia Pharmaceuticals, Bayer Corp., Bayer Pharmaceuticals, LaJolla Pharmaceuticals, and Mallinckrodt; and other interests or relationships with NephroNet, Inc. (CEO and board member). D.E. Williamson reports consultancy for American Renal Associates; ownership interest in American Renal Associates; research funding from Medtronic, Inc.; and an advisory or leadership role for American Renal Associates, CloudCath, and the New England NKF Medical Advisory Board. W.C. Winkelmayer reports consultancy for Akebia, AstraZeneca, Bayer, Boehringer Ingelheim, GlaxoSmithKline, Eli Lilly, Merck, Otsuka, Pharmacosmos, and Reata; honoraria from Akebia, AstraZeneca, Bayer, Boehringer Ingelheim, GlaxoSmithKline, Eli Lilly, Merck, Otsuka, Pharmacosmos, and Reata; and an advisory or leadership role for the American Journal of Kidney Diseases, the American Journal of Nephrology, CJASN, the Journal of the American Medical Association (associate editor; with stipend), Kidney Disease: Improving Global Outcomes (KDIGO; co-chair), and Seminars in Dialysis (editorial boards). All remaining authors have nothing to disclose., (Copyright © 2022 by the American Society of Nephrology.)

Introduction: Atrial fibrillation (AF) is common in patients with kidney failure on hemodialysis (KF-HD). We determined both AF incidence and burden in patients with KF-HD using implantable loop recorder (ILR) monitoring ., Methods: Patients with KF-HD were enrolled and received an ILR. In 6 monitoring months, the incidence of AF events lasting ≥6 minutes was captured. Demographic, clinical, and dialysis characteristics were collected, and associations with incident AF were estimated using negative binomial regression models and expressed as incidence rate ratios and 95% CIs., Results: We enrolled 66 patients with KF-HD (mean age = 56 years, 70% male); 59 (90%) were without previously diagnosed AF. AF lasting ≥6 minutes was detected in 18 of 59 subjects (31%) without previously diagnosed AF and in 5 of 7 subjects (71%) with a previous AF diagnosis. Among the 23 with detected AF, episodes were present on 16% of patient days. Although 14 of 23 patients (61%) had AF on <5% of monitored days, the average duration of AF episodes was <1 hour in 13 of 23 patients (52%). Among patients with AF ≥6 minutes, 19 of 23 (83%) had a CHA 2 DS 2 -VASc score ≥2. When investigating individual HD parameters, higher dialysate calcium (>2.5 vs. 2.5 mEq/l: incidence rate ratio = 0.62; 95% CI, 0.48-0.80) was associated with lower AF risk whereas higher dialysate bicarbonate concentrations (>35 vs. 35 mEq/l: incidence rate ratio = 3.18; 95% CI, 1.13-8.94) were associated with higher AF risk., Conclusion: New AF was detected in approximately one-third of patients with KF-HD. AF affects a substantial proportion of patient days and may be an underappreciated cause of stroke in KF-HD., (© 2021 International Society of Nephrology. Published by Elsevier Inc.)

Background: There is a paucity of contemporary data examining electrolyte changes during and immediately after hemodialysis (HD), and their relationship with dialysate prescriptions. The present study examines these relationships., Methods: We analyzed patient- (n=66) and HD session-level pre- and post-dialysis laboratory data (n=1,713) over a six-month period from the Monitoring in Dialysis Study. We fit mixed effects regression models to analyze electrolyte, blood urea nitrogen, creatinine, and albumin levels immediately post-HD, accounting for pre-HD and dialysate prescriptions. In a subset of US patients (n=40), 15-minute post-HD and 30-minute post-HD values were available at one session. Predictive models were fit to estimate electrolyte levels immediately post-HD, accounting for pre-HD concentrations and dialysate prescriptions., Results: Serum bicarbonate, calcium, and albumin increased (mean increase 4.9±0.3 mEq/L, 0.7±0.1 mEq/L, and 0.4±0.03 g/dL, respectively), whereas potassium, magnesium, and phosphorus decreased immediately post-HD (mean -1.2±0.1 mEq/L, -0.3±0.03 mEq/L, and -3.0±0.2 mg/dL, respectively). Hypokalemia and hypophosphatemia were present in 40% of and 67% of immediate post-HD samples, respectively. Dynamic changes were observed in electrolyte concentrations at 15- and 30-minutes post-HD, compared to immediately post-HD., Conclusion: We describe the magnitude of post-dialytic changes in serum electrolytes with contemporary HD, reporting a high incidence of electrolyte abnormalities post-HD, and present predictive nomograms relating electrolyte changes immediately post-HD to dialysate prescriptions. Our results may be useful for clinical care and provide insights for future research on dialysate prescriptions.

Background and Objectives: Patients receiving maintenance hemodialysis (HD) have a high incidence of cardiac events, including arrhythmia and sudden death. Intradialytic hypotension (IDH) is a common complication of HD and is associated with development of reduced myocardial perfusion, a potential risk factor for arrhythmia., Design, Setting, Participants, & Measurements: We analyzed data from the Monitoring in Dialysis study, which used implantable loop recorders to detect and continuously monitor electrocardiographic data from patients on maintenance HD ( n =66 from the United States and India) over a 6-month period ( n =4720 sessions). Negative binomial mixed effects regression was used to test the association of IDH 20 (decline in systolic BP >20 mm Hg from predialysis systolic BP) and IDH 0-20 (decline in systolic BP 0-20 mm Hg from predialysis systolic BP) with clinically significant arrhythmia (bradycardia≤40 bpm for ≥6 seconds, asystole≥3 seconds, ventricular tachycardia ≥130 bpm for ≥30 seconds, or patient-marked events) during HD., Results: The median age of participants was 58 (25th-75th percentile, 49-66) years; 70% were male; and 65% were from the United States. IDH occurred in 2251 (48%) of the 4720 HD sessions analyzed, whereas IDH 0-20 occurred during 1773 sessions (38%). The number of sessions complicated by least one intradialytic clinically significant arrhythmia was 27 (1.2%) where IDH 20 occurred and 15 (0.8%) where IDH 0-20 occurred. Participants who experienced IDH 20 (versus not) had a nine-fold greater rate of developing an intradialytic clinically significant arrhythmia (incidence rate ratio, 9.4; 95% confidence interval, 3.0 to 29.4), whereas IDH 0-20 was associated with a seven-fold higher rate (incidence rate ratio, 7.2; 95% confidence interval, 2.1 to 25.4)., Conclusions: IDH is common in patients on maintenance HD and is associated with a greater risk of developing intradialytic clinically significant arrhythmia., (Copyright © 2020 by the American Society of Nephrology.)

Objectives: The aim of this study was to assess the utility of left ventricular (LV) entropy, a novel measure of myocardial heterogeneity, for predicting cardiovascular events in patients with dilated cardiomyopathy (DCM)., Background: Current risk stratification for ventricular arrhythmia in patients with DCM is imprecise. LV entropy is a measure of myocardial heterogeneity derived from cardiac magnetic resonance imaging that assesses the probability distribution of pixel signal intensities in the LV myocardium., Methods: A registry-based cohort of primary prevention implantable cardioverter-defibrillator patients with DCM had their LV entropy, late gadolinium enhancement (LGE) presence, and LGE mass measured on cardiac magnetic resonance imaging. Patients were followed from implantable cardioverter-defibrillator placement for arrhythmic events (appropriate implantable cardioverter-defibrillator therapy, ventricular arrhythmia, or sudden cardiac death), end-stage heart failure events (cardiac death, transplantation, or ventricular assist device placement), and all-cause mortality., Results: One hundred thirty patients (mean age 55 years, 83% men, LV ejection fraction 29%, mean LV entropy 5.58 ± 0.72, LGE present in 57%) were followed for a median of 3.2 years. Eighteen (14.0%) experienced arrhythmic events, 17 (13.1%) experienced end-stage heart failure events, and 7 (5.4%) died. LV entropy provided substantial improvement of predictive ability when added to a model containing clinical variables and LGE mass (hazard ratio: 3.5; 95% confidence interval: 1.42 to 8.82; p = 0.007; net reclassification index = 0.345, p = 0.04). For end-stage heart failure events, LV entropy did not improve the model containing clinical variables and LGE mass (hazard ratio: 2.03; 95% confidence interval: 0.78 to 5.28; p = 0.14). Automated LV entropy measurement has excellent intraobserver (mean difference 0.04) and interobserver (mean difference 0.03) agreement., Conclusions: Automated LV entropy measurement is a novel marker for risk stratification toward ventricular arrhythmia in patients with DCM., (Copyright © 2019. Published by Elsevier Inc.)

Background: Hemodialysis patients have high rates of sudden death, but relationships between serum electrolytes, the dialysis prescription, and intra-dialytic shifts in fluid and electrolyte with arrhythmia are uncertain., Methods: We analyzed sixty-six hemodialysis patients who underwent loop recorder implantation with continuous electrocardiographic monitoring, weekly to bi-weekly testing of pre- and post-dialysis electrolytes, and detailed capture of dialysis prescription and flow sheet data for 6 months. The incidence rate ratio (IRR) of reviewer confirmed arrhythmias (RCA) during dialysis through 8 h after dialysis and associations with serum chemistries and dialytic parameters were assessed using adjusted, negative-binomial regression., Results: Among 66 individuals with a mean age of 56 years, 12,480 events were detected in 64 (97%) patients. RCA nadired 12-24 h after dialysis and increased during the final 12 h of the inter-dialytic interval through the first 8 h after dialysis. Higher pre-dialysis serum magnesium concentration was associated with lower incidence rate ratio for arrythmia (IRR per 1 mg/dL increase 0.49, 95% CI; 0.25, 0.94), as was dialysate calcium concentration > 2.5 mEq/L vs. 2.5 mEq/L (IRR 0.52, 95% CI: 0.39, 0.70). Neither intradialytic serum potassium nor weight change were significantly associated with RCA rate. However, there was effect modification such that arrhythmia rate was maximal with concurrently high intradialytic volume and potassium removal (P interaction  = 0.01)., Conclusions: Intra and post-dialytic arrhythmias are common in hemodialysis. Additional studies designed to further elucidate whether modification of the serum magnesium concentration, dialysate calcium concentration, and the extent of intradialytic potassium and fluid removal reduces the risk of per-dialytic arrhythmia are warranted., Trial Registration: Clinicaltrials.gov NCT01779856. Prospectively registered on January 22, 2013.

Objectives: This study sought to evaluate the incidence and significance of atrioventricular (AV) block associated with ventricular arrhythmia (VA) ablation., Background: Attempted ablation of VAs that arise from the septum carries a risk of AV block., Methods: Data from 1,418 patients who had catheter ablation for drug-refractory VAs were evaluated. Two analyses were conducted. The first analysis assessed the patient and procedure characteristics associated with ablation-induced AV block. The second analysis investigated outcome differences between patients with and without AV block. For the second analysis, patients with AV block (Group I) were compared with a 1:2 propensity score-matched control group (Group II) and with patients with pre-existing AV block before ablation (Group III)., Results: Twenty-one (1.6%) patients developed AV block. In multivariable analysis, nonischemic cardiomyopathy (odds ratio: 3.33; 95% confidence interval: 1.32 to 8.40; p = 0.011) and transcoronary ethanol ablation (odds ratio: 46.50; 95% confidence interval: 14.10 to 153.00; p < 0.001) were independently associated with AV block. Subsequent to the AV block, 9 patients were upgraded from an implantable cardioverter-defibrillator to cardiac resynchronization therapy with defibrillator (CRT-D), 2 had de novo CRT-D implantation, 5 had pre-existing CRT-D, and 5 had pacing without CRT. VAs recurred in 33% of patients in Group I, 17% in Group II (log-rank p = 0.842), and 35% in Group III (p = 0.636). The composite outcome of heart failure hospitalization, heart transplantation, or death occurred in 29% of patients in Group I, 17% in Group II (p = 0.723), and 45% in Group III (p = 0.303)., Conclusions: Complete AV block occurs in fewer than 2% of patients undergoing VA ablation and does not appear to be associated with the worse outcome of heart failure hospitalization, heart transplantation, or death., (Copyright © 2019 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: Atrial fibrillation (AF) is a major risk factor for stroke, which is the leading cause of cardiovascular mortality in sub-Saharan Africa. However, there is limited population-based epidemiological data on AF in sub-Saharan Africa. We sought to estimate the prevalence and correlates of AF in rural Uganda., Methods: We conducted a cross-sectional study using community health fairs in 2015 targeting eight villages in rural Uganda. Study participants completed a medical history, a clinical exam, blood collection, and 12‑lead electrocardiographic (ECG) screening. Of 1814 participants enrolled in a parent cohort study that includes 98% of adults residing in the geographic area, 856 attended a health fair and were included in this study. Our primary outcome was AF or atrial flutter. We modelled population prevalence of the outcome with inverse probability of treatment weighting using data collected from the full population., Results: 856 (47.2%) adults in the area attended a health fair and were included in the analysis. Health fair attendees were older (42 vs 34 years, P < 0.0001), in worse self-reported health (P < 0.0001) and more likely to be female (62% vs 49%, P < 0. 0001) compared with non-attendees. After applying weights, the estimated population mean age was 37.7 ± 14.9 years. 15% of the population was overweight or obese and 1.9% had left atrial enlargement on ECG. Despite this, the weighted estimate of AF was 0% (95%CI 0-0.54%)., Conclusions: AF appears less prevalent in rural Uganda than in developed countries. The explanations for this finding may be genetic, environmental or related to survivorship bias., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Introduction: Atrial fibrillation (AF) ablation is increasingly common, but is associated with potential major complications. Technology, experience, and protocols have evolved significantly in recent times, and may have impacted procedural safety. We sought to compare AF ablation safety profiles, including complication rates and fluoroscopy times in a "modern" versus "historical" cohort., Methods and Results: We evaluated consecutive patients undergoing AF ablation from a modern cohort (MC) from 2014 to 2015 and a historic cohort (HC) from 2009 to 2011 for complications. Major complications were categorized according to Heart Rhythm Society guidelines. We included 1,425 patients, 726 in the HC and 699 in the MC. The MC was older, had more OSA and less valvular AF. Fifty-two (3.5%) procedures suffered major complications across the cohorts, with significantly fewer in the MC (5.0% vs. 2.3%, P  =  0.007). The largest reductions were seen in vascular, hemorrhagic, ischemic stroke, and perforation/tamponade related complications. Periprocedural antiplatelets drugs (aHR 2.1 [95 CI 1.1-3.9], P  =  0.02) and force-sensing catheters (aHR 0.4 [95 CI 0.2-0.9], P  =  0.03) were independently related to major complication rates. Direct oral anticoagulants and uninterrupted anticoagulation were not associated with complications. There was a decrease in both fluoroscopy (-17.4 minutes [95 CI 19.2-15.6], P < 0.0001) and radiofrequency ablation times (-561 seconds [95CI -750 to -371], P < 0.0001)., Conclusions: The safety profile of AF ablation has improved significantly in less than a decade., (© 2018 Wiley Periodicals, Inc.)

Aims: A commonly held notion is that patients with a family history of atrial fibrillation (AF) have worse atrial substrate and higher rates of arrhythmia recurrence following ablation. We sought to examine differences in atrial substrate and catheter ablation outcomes in patients with a 1st degree family member with paroxysmal or persistent AF (PeAF) compared to those without., Methods and Results: A total of 256 consecutive patients undergoing their 1st ablation for AF (123 paroxysmal, 133 persistent) with >1 year follow up were included. The presence of one 1st-degree family relative was defined as a 'positive family history'. Clinical characteristics, electroanatomic map findings, ablation characteristics and outcomes were compared in patients with and without a positive family history of AF. Patients with paroxysmal fibrillation with a positive family history (n = 57; 46%) had similar clinical characteristics and arrhythmia recurrence after catheter ablation as those without. Of those that recurred, patients with a positive family history were more likely to have progressed to PeAF (P = 0.05). Patients with PeAF with a positive family history (n = 75; 56%) had similar clinical characteristics, electroanatomic mapping findings and ablation characteristics, but worse long term arrhythmia free survival (P = 0.04)., Conclusion: The presence of a 1st-degree family member with AF does not impact the clinical outcomes of catheter ablation for paroxysmal AF. However, a positive family history is associated with worse arrhythmia free survival in patients with PeAF. This finding is not explained by differences in clinical characteristics, atrial substrate assessed by voltage maps or ablation characteristics.

Objectives: This study sought to examine the relationship between the number of oral antiarrhythmic drug (AAD) failures before referral for ventricular tachycardia (VT) ablation and subsequent clinical outcomes., Background: Failure of AADs prompts referral for VT ablation., Methods: Consecutive patients (n = 669) with sustained VT who were referred for a first-time ablation were divided into 2 groups according to the number of oral Class 1 or 3 AAD failures before referral: single-drug failure (≤1 AAD; n = 256) or multidrug failure (>1 AADs; n = 413). Outcomes were stratified according to underlying disease type (no structural heart disease [SHD] [n = 87]; ischemic cardiomyopathy [ICM] [n = 368]; and ischemic cardiomyopathy [NICM] [n = 214]) and reported at a mean follow-up of 35 ± 46 months., Results: Patients with multidrug failure, compared with patients with single-drug failure, had more advanced SHD and required more extensive ablation to control arrhythmia. Multidrug failure, compared with single-drug failure, was associated with lower ventricular arrhythmia-free survival in ICM (46 ± 4% vs. 58 ± 6%; p = 0.03) and NICM (26 ± 5% vs. 49 ± 6%; p = 0.008), but not in the absence of SHD (71 ± 8% vs. 85 ± 7%; p = 0.10). Overall survival was lower in multidrug failure versus single-drug failure groups in patients with ICM (71 ± 3% vs. 84 ± 4%; p = 0.03) and NICM (70 ± 5% vs. 88 ± 4%; p < 0.001). Multidrug failure was independently associated with a higher risk of ventricular arrhythmia recurrence (hazard ratio: 1.6; p = 0.01) and mortality in NICM (hazard ratio: 2.6; p = 0.008), but not in ICM., Conclusions: Patients with SHD and failure of multiple oral AADs before VT ablation referral have more advanced heart disease and worse clinical outcomes following ablation, especially in NICM., (Crown Copyright © 2018. Published by Elsevier Inc. All rights reserved.)

Sudden death is one of the more frequent causes of death for hemodialysis patients, but the underlying mechanisms, contribution of arrhythmia, and associations with serum chemistries or the dialysis procedure are incompletely understood. To study this, implantable loop recorders were utilized for continuous cardiac rhythm monitoring to detect clinically significant arrhythmias including sustained ventricular tachycardia, bradycardia, asystole, or symptomatic arrhythmias in hemodialysis patients over six months. Serum chemistries were tested pre- and post-dialysis at least weekly. Dialysis procedure data were collected at every session. Associations with clinically significant arrhythmias were assessed using negative binomial regression modeling. Sixty-six patients were implanted and 1678 events were recorded in 44 patients. The majority were bradycardias (1461), with 14 episodes of asystole and only one of sustained ventricular tachycardia. Atrial fibrillation, although not defined as clinically significant arrhythmias, was detected in 41% of patients. With thrice-weekly dialysis, the rate was highest during the first dialysis session of the week and was increased during the last 12 hours of each inter-dialytic interval, particularly the long interval. Among serum and dialytic parameters, only higher pre-dialysis serum sodium and dialysate calcium over 2.5 mEq/L were independently associated with clinically significant arrhythmias. Thus, clinically significant arrhythmias are common in hemodialysis patients, and bradycardia and asystole rather than ventricular tachycardia may be key causes of sudden death in hemodialysis patients. Associations with the temporal pattern of dialysis suggest that modification of current dialysis practices could reduce the incidence of sudden death., (Copyright © 2017 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.)

Background: Noninducibility of sustained monomorphic ventricular tachycardia (SMVT) postablation does not insure absence of later recurrence in patients with ischemic cardiomyopathy. This study aims to determine the relation between inducible nonsustained VT postablation and VT recurrences., Methods and Results: One hundred sixty-five consecutive patients (156 male; age 68±9 years) underwent ablation for SMVT because of ischemic cardiomyopathy; 44 patients who did not have induction testing or in whom only ventricular fibrillation was induced after ablation were excluded. In 38 patients (23%), SMVT was inducible (group C). Of the 83 patients without inducible SMVT after ablation, nonsustained VT defined as ≥5 beats lasting for <30 s, was induced in 34 patients (group B, 21%), whereas the remaining 49 patients had no VT induced by the induction test (group A, 30%). Over a median follow-up of 18.7 months, freedom from recurrent VT at 24 months was 60% in group A, 45% in group B ( P =0.017 versus group A), and 38% in group C ( P =0.005 versus group A). In patients without inducible SMVT, inducible nonsustained VT and left ventricular ejection fraction was independently associated with VT recurrence (hazard ratio, 3.66 and 1.07; 95% CI, 1.3-11.1 and 1.01-1.14)., Conclusions: Inducible nonsustained VT postablation suggests the continued presence of functional arrhythmia substrate. Further trials are needed to assess whether additional ablation would improve outcome in this group., (© 2017 American Heart Association, Inc.)

Objectives: The authors sought to investigate the effect of low irrigation flow rate on lesion characteristics and ablation outcomes in a clinicopathological study., Background: Irrigated ablation produces deeper lesions compared with nonirrigated ablation, which may not be desirable in the thin-walled posterior left atrium (LA), where collateral esophageal injury is possible., Methods: Lesions were placed on the smooth posterior right atrium in 20 swine and posterior LA in 60 patients at a maximum power of 20 to 25 W with either: 1) power-controlled ablation at an irrigation flow rate of 17 ml/min (high-flow group 10 swine; n = 40) or 2) temperature-controlled ablation at an irrigation flow rate of 2 ml/min (low-flow group 10 swine; n = 20). Safety and efficacy was also compared in 326 patients undergoing AF ablation using high-flow (n = 160) or low-flow settings (n = 166) for posterior LA ablation., Results: Low-flow, compared with high-flow, lesions in swine had a higher incidence of lesions with: impedance fall ≥10 Ω, loss of pace capture, electrograms characteristic of transmural lesions, and visible lesions on anatomic inspection (p < 0.05 for all). Low-flow lesions had a maximal diameter at the endocardial surface, whereas high-flow lesions had a maximal diameter at the epicardial surface. In humans, impedance, pace capture, and transmurality data also strongly favored low-flow lesions. There was no difference in acute pulmonary vein isolation, complications, or 12-month arrhythmia-free survival between the groups., Conclusions: Low-flow irrigated ablation provides favorable lesion characteristics for posterior LA ablation without increasing the risk of adverse events., (Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Patients on rivaroxaban have variable international normalized ratios (INRs) but it is uncertain if INR impacts procedural heparin requirement during left atrial ablation. We sought to examine the determinants of heparin dosing in this patient population., Methods: We reviewed consecutive patients who received rivaroxaban within 24 hours of left atrial ablation and compared them to patients on uninterrupted warfarin. The determinants of heparin requirement were evaluated using regression analysis. We then tested a weight-based heparin dose prospectively in rivaroxaban patients., Results: There were 258 patients on rivaroxaban and 213 on warfarin. The mean INR was 1.4 in the rivaroxaban group and 2.3 in the warfarin group (P < 0.01). To achieve an activated clotting time (ACT) >350 seconds, rivaroxaban patients required significantly more heparin (166.9 vs. 78.3 units/kg, P < 0.001). In the rivaroxaban group, body weight was the strongest predictor of heparin dose (r = 0.52), while INR was weakly correlated (r = -0.21). In the prospective group, 25 patients were given an initial heparin dose of 120 units/kg with 22/25 (88%) achieving an ACT > 300 seconds. There were seven and three cases of pericardial effusion in rivaroxaban and warfarin patients, respectively (P = 0.41). The average volume drained in the rivaroxaban group was elevated (988.6 vs. 275.0 mL, P = 0.21)., Conclusions: Body weight is the strongest predictor of procedural heparin requirement during left atrial ablation in patients on uninterrupted rivaroxaban, even in those with an elevated INR. A heparin dose of 120 units/kg achieves an ACT > 300 seconds in the majority of patients. In cases of pericardial effusion, bleeding may be prolonged., (© 2017 Wiley Periodicals, Inc.)

Aims: Catheter ablation can be lifesaving in ventricular tachycardia (VT) storm, but the underlying substrate in patients with storm is not well characterized. We sought to compare the clinical factors, substrate, and outcomes differences in patients with sustained monomorphic VT who present for catheter ablation with VT storm versus those with a nonstorm presentation., Methods: Consecutive ischemic (ICM; n = 554) or nonischemic cardiomyopathy patients (NICM; n = 369) with a storm versus nonstorm presentation were studied (ICM storm 186; NICM storm 101)., Results: In ICM, storm compared with nonstorm patients had significantly lower left ventricular (LV) ejection fraction (EF), greater number of antiarrhythmic drug (AAD) failures, slower VTs, greater number of scarred LV segments, higher incidence of anterior, septal, and apical endocardial LV scar (all P < 0.05). However, outcomes in follow-up were similar (12-month ventricular arrhythmia [VA]-free survival: 51% vs. 52%, P = 0.6; survival free of death/transplant 75% vs. 87%, P = 0.7). In addition to the above differences, NICM storm patients were also older; however, the extent and distribution of scar was similar except for a higher incidence of lateral endocardial scar in storm patients (P = 0.05). VA-free survival (36% vs. 47%, P = 0.004) and survival free of death/transplant, however, were worse in NICM storm than nonstorm patients (72% vs. 88%, P = 0.001). NICM storm patients had worse VA-free survival than ICM storm patients., Conclusion: There are differences in clinical factors and scar patterns in patients undergoing VT ablation who present with VT storm versus those with a nonstorm presentation. Clinical outcomes are worse in NICM storm patients., (© 2016 Wiley Periodicals, Inc.)

Background: Long-term outcomes after ventricular tachycardia (VT) ablation are sparsely described., Objectives: The purpose of this study was to describe long-term prognosis after VT ablation in patients with no structural heart disease (no SHD), ischemic cardiomyopathy (ICM), and nonischemic cardiomyopathy (NICM)., Methods: Consecutive patients (N = 695: no SHD, 98; ICM, 358; NICM, 239) ablated for sustained VT were followed for a median of 6 years. Acute procedural parameters (complete success [noninducibility of any VT]) and outcomes after multiple procedures were reported., Results: Compared with patients with no SHD or NICM, patients with ICM were the oldest, were more likely to be men, lowest left ventricular ejection fraction, highest drug failures, VT storms, and number of inducible VTs. Complete procedure success was highest in patients with no SHD than in patients with ICM and those with NICM (79%, 56%, 60%, respectively; P < .001). At 6 years, ventricular arrhythmia (VA)-free survival was highest in patients with no SHD (77%) than in patients with ICM (54%) and those with NICM (38%) (P < .001), and overall survival was lowest in patients with ICM (48%), followed by patients with NICM (74%) and patients with no SHD (100%) (P < .001). Age, left ventricular ejection fraction, presence of SHD, acute procedural success (noninducibility of any VT), major complications, need for nonradiofrequency ablation modalities, and VA recurrence were independently associated with all-cause mortality., Conclusion: Long-term follow-up after VT ablation shows excellent prognosis in the absence of SHD, highest VA recurrence, and transplantation in patients with NICM and highest mortality in patients with ICM. The extremely low mortality for those without SHD suggests that VT in this population is rarely an initial presentation of a myopathic process., (Copyright © 2016 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)