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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.)

Introduction: Factors influencing malignant arrhythmia onset are not fully understood. We explored the circadian periodicity of ventricular arrhythmias (VAs) in patients with implantable cardioverter and cardiac resynchronization defibrillators (ICD/CRT-D)., Methods: Time, morphology (monomorphic/polymorphic), and mode of termination (anti-tachycardia pacing [ATP] or shock) of VAs stored in a database of remote monitoring data were adjudicated. Episodes were grouped in six 4-h timeslots from 00:00 to 24:00. Circadian distributions and adjusted marginal odds ratios (ORs), with 95% confidence interval (CI), were analyzed using mixed-effect models and logit generalized estimating equations, respectively, to account for within-subject correlation of multiple episodes., Results: Among 1303 VA episodes from 446 patients (63% ICD and 37% CRT-D), 120 (9%) self-extinguished, and 842 (65%) were terminated by ATP, 343 (26%) by shock. VAs clustered from 08:00 to 16:00 with 44% of episodes, as compared with 22% from 00:00 to 08:00 (p < .001) and 34% from 16:00 to 24:00 (p = .005). Episodes were more likely to be polymorphic at night with an adjusted marginal OR of 1.66 (CI, 1.15-2.40; p = .007) at 00:00-04:00 versus other timeslots. Episodes were less likely to be terminated by ATP in the 00:00-04:00 (success-to-failure ratio, 0.67; CI, 0.46-0.98; p = .039) and 08:00-12:00 (0.70; CI, 0.51-0.96; p = .02) timeslots, and most likely to be terminated by ATP between 12:00 and 16:00 (success-to-failure ratio 1.42; CI, 1.06-1.91; p = .02)., Conclusion: VAs did not distribute uniformly over the 24 h, with a majority of episodes occurring from 08:00 to 16:00. Nocturnal episodes were more likely to be polymorphic. The efficacy of ATP depended on the time of delivery., (© 2021 Wiley Periodicals LLC.)

Objectives: This study evaluated the temporal association between atrial high-rate episodes (AHREs) and sustained ventricular arrhythmias (VAs) in a remotely monitored cohort with implantable cardioverter-defibrillators (ICD) with and/or without cardiac resynchronization therapy with a defibrillator (CRT-D)., Background: Clinical relevance of AHREs in terms of VA rate and survival has not been outlined yet., Methods: This study analyzed data of patients with ICDs and CRT-Ds from the nationwide Home Monitoring Expert Alliance network. The cohort included 2,435 patients with a median follow-up of 25 months (interquartile range: 13 to 42 months) and age 70 years (range 61 to 77 years); 19.7% were women, 51.4% had coronary artery disease, and 45.2% had a CRT-D. There were 3,410 appropriate VA episodes; 498 (14.6%) were preceded by AHREs within 48 h; in 85.5% of this group, AHREs were still ongoing at episode onset., Results: In a longitudinal analysis, the odds ratios (ORs) of experiencing any VA in a 30-day interval with AHREs versus intervals without AHREs were 2.35 (95% confidence interval [CI]: 1.86 to 2.97; p < 0.001) for ventricular tachycardia (VT), 3.06 (95% CI: 2.35 to 3.99; p < 0.001) for fast VT, 1.84 (95% CI: 1.36 to 2.48; p < 0.001) for self-extinguishing ventricular fibrillation (VF), and 2.31 (95% CI: 1.17 to 4.57; p = 0.01) for VF. ORs decreased with increasing AHRE burden. Patients with AHREs 48 h before VAs were more likely to experience VA recurrences (adjusted hazard ratio [HR]: 1.78; 95% CI: 1.41 to 2.24; p < 0.001) and had higher overall mortality (HR: 2.67; 95% CI: 1.68 to 4.23; p < 0.001)., Conclusions: AHREs were not uncommon 48 h before VAs, which tended to be distributed around intervals with AHREs. Temporal connection between AHREs and VAs was a marker of increased risk of VA recurrence and a poorer prognosis., (Copyright © 2019 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: The occurrence of sustained ventricular arrhythmias (SVA) may be influenced by environmental factors. We aimed to investigate annual periodic trends of SVA from the intracardiac electrograms (IEGMs) stored in the implantable defibrillators (ICDs) or cardiac resynchronization therapy (CRT-D) recipients., Methods: Data from the Home Monitoring Expert Alliance project, a pooled repository of remote monitoring transmissions were analyzed. All IEGMs stored were independently adjudicated by three cardiac electrophysiologists. Periodicity of SVA was evaluated with Generalized Estimating Equations (GEE) models, including periodic terms depending on months in a year., Results: A total of 2936 ICD/CRT-D patients (median age 70 years, 79.6% male) were followed for a median period of 25[13-44] months. Most prevalent structural heart diseases were ischemic (50.8%) and idiopathic dilated (30.6%) cardiomyopathies. Overall, 942 (32.1%) patients experienced a total of 4824 SVA. At GEE analysis, we found a significant periodic component (p = 0.048) when considering both shocked and non-shocked episodes. SVA less frequently occurred in Junes and Julies (3.7 × 1000 patient-month). No evidence of significant periodicity was collected in the subgroup of ischemic patients., Conclusions: In this RM-based cohort of ICD/CRT-T patients, we observed an annual periodicity of SVA occurrence, with a lower incidence in summer months., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Background: The aim of this study was to assess long-term results and adverse events in patients with ventricular tachycardia from different etiologies., Methods: The recurrence rate of tachycardia, consequent further therapies (other catheter ablation procedures, drug therapy and implantable defibrillator) and clinical events have been assessed in 60 consecutive patients undergoing ventricular tachycardia catheter ablation between January 2000 and December 2004., Results: During a median follow-up of 20 months (interquartile range 13-36 months), tachycardia recurred in 27 patients (45%) after a median of 3 months (interquartile range 1-12 months). A second procedure was performed in 11 patients; it was successful in 8 patients. Four patients underwent pharmacological therapy which was successful in all cases. Overall, after ablation (> or =1 procedures) and pharmacological therapy, tachycardia was cured in 75% of cases. All the 20 patients without structural heart disease were cured with ablation vs. 62% of patients with heart disease (p = 0.001). Patients with dilated cardiomyopathy reported worst results (33% success, p = 0.03). Recurrences were predicted by acute failure of procedure (p = 0.05), presence of heart disease (p = 0.006) and history of atrial arrhythmias (p = 0.02). On a multivariate analysis, only structural heart disease continued to be an independent predictor of ventricular tachycardia recurrence., Conclusions: Catheter ablation of ventricular tachycardia has a high percentage of recurrences in patients with heart disease, whereas is curative in subjects without structural heart disease.

The simultaneous occurrence of narrow and wide QRS complex tachycardias was observed in 2 patients evaluated at our electrophysiological centers. Electrophysiological testing revealed the coexistence of two types of arrhythmia (atrioventricular nodal reentrant tachycardia and verapamil-sensitive left ventricular tachycardia) in one patient and of three types of arrhythmia (atrioventricular nodal reentrant tachycardia, ventricular tachycardia originating from the right ventricular outflow tract, and left ventricular tachycardia) in the other. Both patients underwent successful radiofrequency ablation of all the types of tachycardia.