The benefit of closed loop stimulation in patients with cardioinhibitory vasovagal syncope confirmed by head-up tilt table testing: a systematic review and meta-analysis.

Abstract

A proportion of patients with vasovagal syncope (VVS) experience recurrence despite appropriate management. Closed loop stimulation (CLS) pacing is a promising treatment for a subgroup of patients with cardioinhibitory response on head-up tilt table test (HUTT). Nonetheless, its efficacy remains uncertain. We sought to assess the efficacy of CLS pacing in patients with cardioinhibitory VVS. We searched PubMed, Google Scholar, and the Cochrane Central Register of controlled trials for relevant studies (last search date April 23, 2018). Data were pooled using the Mantel-Haenszel fixed-effects model. For cohort studies, we used a Freeman-Tukey transformation to calculate the weighted summary proportion. Primary outcomes are syncope and presyncope. Eight studies were included in the final analyses (two single-blinded and one double-blinded RCT, two prospective observational studies, and three retrospective observational studies). Two hundred ninety-one patients included, with an average age of 57years. Quality of evidence is moderate. Use of CLS pacing was associated with reduced risk of syncope (OR 0.08; 95% CI 0.03-0.18; I2 32%) and presyncope (OR 0.34; 95% CI 0.18-0.63; I2 0.00%). Using proportion meta-analysis, the summary estimate of the proportion of cases that developed syncope during CLS pacing was similar between RCTs and prospective studies (3.2% and 3.1%), respectively. This is much lower than the rate of recurrence in the control arm of RCTs at 33.7%. Sensitivity analyses yielded similar results. CLS pacing is beneficial for patients with recurrent vasovagal syncope who demonstrate a cardioinhibitory response on HUTT.