A systematic review on recurrent cardioinhibitory vasovagal syncope: Does pacing therapy break the fall?

Vasovagal reflex is the most common cause of syncope. Pacemaker with rate drop response (RDR) or closed‐loop stimulation (CLS) anti‐syncope algorithms have been studied in recurrent vasovagal syncope (VVS), with conflicting results. We aim to investigate the role of pacemaker therapy and anti‐syncope pacing mode in cardioinhibitory recurrent VVS. MEDLINE, Cochrane Library and registered clinical trials were searched for single or double‐blind randomized controlled trials on pacing as a treatment for recurrent VVS. Five studies were eligible, overall enrolling 228 patients. After pooling data from all trials, pacemaker therapy showed a 63% reduction in syncope recurrence compared to control [Risk Ratio (RR): 0.37; 95% CI: 0.14‐0.98; I2 = 67%)]. Subgroup analyses suggested that the effect was greater in single‐blind studies (RR: 0.07; 95% CI: 0.01‐0.52, I2 = 0%). When comparing pacing algorithms, the results from RDR versus no pacing trials (n = 2) did not show a significant reduction in syncope recurrence (RR: 0.73; 95% CI: 0.25‐2.16, I2 60 = 75%). In contrast, the data from the CLS versus standard pacing trials (n = 3) evidenced a statistically meaningful reduction in syncopal burden (RR: 0.18; 95% CI: 0.07‐0.47, I2 = 0%). It is unclear whether pacemaker therapy reduces syncopal burden in cardioinhibitory recurrent VVS. However, our results suggest effectiveness of CLS pacing mode.