Does cardiac pacing reduce syncopal recurrences in cardioinhibitory vasovagal syncope patients selected with head-up tilt test? Analysis of a 5-year follow-up database.

Purpose: Benefit of cardiac pacing in patients with vasovagal syncope (VVS) and cardioinhibitory response to head-up tilt test (HUTT) is still debated. We aimed at retrospectively assessing the long-term effect of cardiac pacing in a cohort routinely followed in our institutions.

Methods And Results: From a cohort of 1502 patients who performed HUTT between 2008 and 2014, 181 (12%) patients had VASIS 2A (40) or 2B (141) response (median age 43 [interquartile range, 25-56] years, 59% male). Fifty patients (28%) received a dual-chamber pacemaker and 131 (72%) received training on physical maneuvers and medical therapy. The so-called 'Closed Loop Stimulation' (CLS) function was activated for at least 18 months in the pacing group. The 5-year recurrence rate of syncope of paced patients was compared with non-paced patients and with a subgroup of 18 propensity-score matched patients selected among non-paced patients. The 5-year Kaplan-Meier syncope free-rate was 81% (CI, 67%-90%) in the pacing group, 57% (47%-67%; p = 0.004) in the unmatched control group, 53% (27%-74%; p = 0.005) in the 18 propensity-matched patients. The hazard ratio of pacing versus non-pacing was 0.34 (CI, 0.18-0.70) when comparing with the whole non-pacing control group, and 0.25 (CI, 0.09-0.65) including only the propensity-score matched subgroup. No deaths were observed during the follow-up.

Conclusions: In the selected VVS population with HUTT-induced cardioinhibitory response, pacemaker therapy with CLS function was associated to 66% relative and 24% absolute risk reduction of 5-year syncopal recurrence rate. Benefit was confirmed after controlling variables affecting propensity for pacemaker therapy.