P6633Pacing as a treatment for recurrent cardioinhibitory vasovagal syncope: systematic review with meta-analysis

Introduction: Vasovagal reflex is the most common cause of syncopal episodes, mostly considered a benign condition. However, some patients have recurring episodes and/or major trauma associated with syncope, thus compromising quality-of-life. Pacemaker with rate drop response (RDR) and Closed-Loop Stimulation (CLS) algorithms have been investigated in recurrent vasovagal syncope (R-VVS). The latter has shown promise in cardioinhibitory R-VVS (defined as heart rate <40 bpm >10 seconds and/or asystole >3 seconds). Purpose: To define the role of cardiac pacing in cardioinhibitory R-VVS. Methods: MEDLINE, Cochrane Library and registered clinical trials were searched for single or double-blinded placebo-controlled randomized controlled trials (RCT) on cardiac pacing treatment for R-VVS and systematically reviewed for inclusion and further analysis. Results: Five clinical trials met the eligibility criteria, with a total of 254 patients included. Four trials were double-blinded and four had a follow-up of at least one year. Two of them investigated the CLS and three the RDR algorithms. The analysis of all trials (N=5) as well as that of the double-blinded with a follow-up greater than a year (N=3) did not find a significant reduction in recurring syncopal events (RR: 0,53; 95% IC: 0,21–1,34; RR: 0,58; 95% IC: 0,32–1,05, respectively). When analyzing the trials by algorithm, the RDR pacemaker has shown no significant advantage (RR: 0,74; 95% IC: 0,42–1,29). However, the CLS algorithm was associated with a 22% reduction in the syncopal events (RR: 0,22; 95% IC: 0,08–0,62).