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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 x 1000 patient-month). No evidence of significant periodicity was collected in the subgroup of ischemic patients.Conclusions: In thisRM-based cohort of ICD/ CRT-T patients, we observed an annual periodicity of SVA occurrence, with a lower incidence in summer months. (c) 2018 Elsevier B.V. All rights reserved.

Purpose: Benefit of cardiac pacing in patients with vasovagal syncope (VVS) and cardioinhibitory response to head-up tilt test (HUTT) is still debated. We aimed at retrospectively assessing the long-term effect of cardiac pacing in a cohort routinely followed in our institutions.Methods and results: From a cohort of 1502 patients who performed HUTT between 2008 and 2014, 181 (12%) patients had VASIS 2A (40) or 2B (141) response (median age 43 [interquartile range, 25-56] years, 59% male). Fifty patients (28%) received a dual-chamber pacemaker and 131 (72%) received training on physical maneuvers and medical therapy. The so-called 'Closed Loop Stimulation' (CLS) function was activated for at least 18 months in the pacing group. The 5-year recurrence rate of syncope of paced patients was compared with non-paced patients and with a subgroup of 18 propensity-score matched patients selected among non-paced patients. The 5-year Kaplan-Meier syncope free-rate was 81% (CI, 67%-90%) in the pacing group, 57% (47%-67%; p = 0.004) in the unmatched control group, 53% (27%-74%; p = 0.005) in the 18 propensity-matched patients. The hazard ratio of pacing versus non-pacing was 0.34 (CI, 0.18-0.70) when comparing with the whole non-pacing control group, and 0.25 (CI, 0.09-0.65) including only the propensity-score matched subgroup. No deaths were observed during the follow-up.Conclusions: In the selected VVS population with HUTT-induced cardioinhibitory response, pacemaker therapy with CLS function was associated to 66% relative and 24% absolute risk reduction of 5-year syncopal recurrence rate. Benefit was confirmed after controlling variables affecting propensity for pacemaker therapy. (c) 2018 Elsevier B.V. All rights reserved.