Wenckebach cycle length: A novel predictor for AV block in AVNRT patients treated with ablation

In Vivo Cardiac Electrophysiology in Mice: Determination of Atrial and Ventricular Arrhythmic Substrates

Cardiac arrhythmias are a common cardiac condition that might lead to fatal outcomes. A better understanding of the molecular and cellular basis of arrhythmia mechanisms is necessary for the development of better treatment modalities. To aid these efforts, various mouse models have been developed for studying cardiac arrhythmias. Both genetic and surgical mouse models are commonly used to assess the incidence and mechanisms of arrhythmias. Since spontaneous arrhythmias are uncommon in healthy young mice, intracardiac programmed electrical stimulation (PES) can be performed to assess the susceptibility to pacing-induced arrhythmias and uncover the possible presence of a proarrhythmogenic substrate. This procedure is performed by positioning an octopolar catheter inside the right atrium and ventricle of the heart through the right jugular vein. PES can provide insights into atrial and ventricular electrical activity and reveal whether atrial and/or ventricular arrhythmias are present or can be induced. Here, we explain detailed procedures used to perform this technique, possible troubleshooting scenarios, and methods to interpret the results obtained. © 2024 Wiley Periodicals LLC. Basic Protocol: Programmed electrical stimulation in mice.

Late pacemaker implantation after atrioventricular nodal reentrant tachycardia ablation: A systematic review and meta-analysis

INTRODUCTION

Catheter ablation (CA) of atrioventricular nodal reentrant tachycardia (AVNRT) is associated with late pacemakers for AV block (AVB). We performed a systematic review and meta-analysis of the pooled incidence of late pacemakers for AVB after CA of AVNRT.

METHODS AND RESULTS

Relevant studies were identified from 4 electronic databases (PubMed, EMBASE, Scopus, Cochrane Trial Register) from inception to 2022. A random effects model was used to calculate the odds of late pacemakers in CA of AVNRT compared to atrioventricular reentrant tachycardia (AVRT). Of 533 articles screened, 13 were included in systematic review. CA for AVNRT was performed in 16,471 patients (mean age 54±17 years, 63% females), of which 68 (0.4%) underwent pacemaker implantation for late AVB. Meta-analysis was performed in 5 of the 13 studies (mean follow-up duration 7±4 years). Patients who underwent CA of AVNRT were older (58±17 vs 52±20 years, p<0.001), and more likely female (60% vs 41%, p<0.001) than AVRT. Pooled estimates of late pacemakers for AVB were higher in CA of AVNRT than AVRT (0.5% vs 0.2%, p=0.006), with CA in AVNRT associated with almost 2-fold increased odds of late pacemakers indicated for AVB (OR 1.94, 95%CI 1.08-3.47, p=0.027) compared to AVRT.

CONCLUSION

AVNRT ablation is safe but associated with a low but definitely increased risk of requiring pacing in the later years due to AVB. This association is confirmed by pooling over 16,000 AVNRT patients receiving clinically indicated ablation and is helpful in providing informed consent for prospective patients undergoing ablation for AVNRT. This article is protected by copyright. All rights reserved.