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This international multidisciplinary expert consensus statement is intended to provide comprehensive guidance that can be referenced at the point of care to cardiac electrophysiologists, cardiologists, and other health care professionals, on the management of cardiac arrhythmias in pregnant patients and in fetuses. This document covers general concepts related to arrhythmias, including both brady- and tachyarrhythmias, in both the patient and the fetus during pregnancy. Recommendations are provided for optimal approaches to diagnosis and evaluation of arrhythmias; selection of invasive and noninvasive options for treatment of arrhythmias; and disease- and patient-specific considerations when risk stratifying, diagnosing, and treating arrhythmias in pregnant patients and fetuses. Gaps in knowledge and new directions for future research are also identified., (Copyright © 2023 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Objective: To review the literature systematically to determine whether noninvasive or invasive risk stratification, such as with an electrophysiological study of patients with asymptomatic pre-excitation, reduces the risk of arrhythmic events and improves patient outcomes., Methods: PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials (all January 1, 1970, through August 31, 2014) were searched for randomized controlled trials and cohort studies examining noninvasive or invasive risk stratification in patients with asymptomatic pre-excitation. Studies were rejected for low-quality design or the lack of an outcome, population, intervention, or comparator of interest or if they were written in a language other than English., Results: Of 778 citations found, 9 studies met all the eligibility criteria and were included in this paper. Of the 9 studies, 1 had a dual design-a randomized controlled trial of ablation versus no ablation in 76 patients and an uncontrolled prospective cohort of 148 additional patients-and 8 were uncontrolled prospective cohort studies (n=1,594). In studies reporting a mean age, the range was 32 to 50 years, and in studies reporting a median age, the range was 19 to 36 years. The majority of patients were male (range, 50% to 74%), and <10% had structural heart disease. In the randomized controlled trial component of the dual-design study, the 5-year Kaplan-Meier estimates of the incidence of arrhythmic events were 7% among patients who underwent ablation and 77% among patients who did not undergo ablation (relative risk reduction: 0.08; 95% confidence interval: 0.02 to 0.33; p<0.001). In the observational cohorts of asymptomatic patients who did not undergo catheter ablation (n=883, with follow-up ranging from 8 to 96 months), regular supraventricular tachycardia or benign atrial fibrillation (shortest RR interval >250 ms) developed in 0% to 16%, malignant atrial fibrillation (shortest RR interval ≤250 ms) in 0% to 9%, and ventricular fibrillation in 0% to 2%, most of whom were children in the last case., Conclusions: The existing evidence suggests risk stratification with an electrophysiological study of patients with asymptomatic pre-excitation may be beneficial, along with consideration of accessory-pathway ablation in those deemed to be at high risk of future arrhythmias. Given the limitations of the existing data, well-designed and well-conducted studies are needed., (Copyright © 2016 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Background: Sudden cardiac death is usually caused by ventricular arrhythmias and in many cases, is preceded by frequent ventricular ectopy. It is known that ectopic beats cause transient increases in sympathetic nerve activity (SNA)., Objective: Because high SNA is known to be arrhythmogenic, we hypothesized that high rates of ectopy increase SNA, thereby creating a milieu that favors development of ventricular tachycardia and/or fibrillation., Methods: This study measured muscle SNA, coronary sinus catecholamine, and arterial pressure during graded rates of ventricular ectopy (from 4:1 to 1:1, sinus to ectopic beat ratio) in a total of 21 patients referred for electrophysiologic testing., Results: Both muscle SNA and coronary sinus norepinephrine increased significantly with increased ectopy frequency (P < .05). Moreover, the change in muscle SNA correlated significantly with the change in coronary sinus norepinephrine levels (r = .72, P < .001)., Conclusion: These data demonstrate that sympathoexcitation evoked by high rates of ventricular ectopy can contribute to a state of elevated SNA both in peripheral tissues and within the heart. This altered autonomic state may contribute to an increased susceptibility to life-threatening tachyarrhythmias in patients with high rates of ectopy., (Copyright 2010 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Objectives: The aim of the present study was to evaluate in a prospective randomized fashion the electrophysiologic effects of acute biventricular (BV) pacing. We hypothesized that (1) the local coupling interval in the left ventricle in response to right-sided ventricular premature beats is prolonged when BV pacing is applied during the drive train compared with right ventricular (RV) pacing, and (2) BV programmed electrical stimulation (PES) decreases the induction of ventricular arrhythmias compared with standard RV-PES, regardless of the presence of intraventricular conduction delay., Background: Previous studies have suggested that BV pacing might decrease the frequency of ventricular arrhythmias; however, the mechanism of arrhythmia suppression remains unclear., Methods: Eighteen patients with coronary artery disease were randomized to RV-PES or BV-PES with a repeat study using the other pacing mode. The RV effective refractory periods were measured during RV-PES and BV-PES. In addition, the local LV S(1)-S(2) coupling interval was measured at 600/450 ms and 400/350 ms during RV-PES and BV-PES., Results: BV-PES had no effect on RV effective refractory periods. On the other hand, the local LV S(1)-S(2) coupling intervals increased significantly during BV-PES compared with RV-PES (P < .0001). Ventricular tachycardia was induced in six patients using RV-PES but in only one patient with BV-PES (RR = 83%, P = .01). No difference was observed in the induction of ventricular fibrillation., Conclusions: BV-PES significantly reduced the induction of ventricular tachycardia compared to RV-PES, with no significant effect on ventricular fibrillation induction. Our findings may help explain the reduced incidence of ventricular arrhythmias noted with chronic BV pacing.