Abstract 2346: The Role of Pacemaker in Hypersensitive Carotid Sinus Syndrome
Purpose: About 15% of patients (pts) with pure or predominant cardioinhibitory hypersensitive carotid sinus syndrome (HCS) have no clinical improvement after permanent pacemaker (PP) implantation, and up to 50% continue to have minor symptoms. We aimed to assess the outcome of pts with HCS treated with PP and to determine predictors of symptoms recurrence.
Methods: We retrospectively analysed 138 pts who had PP implantation for cardioinhibitory or mixed HCS during 18 years. Diagnosis was made based on cardioinhibition (asystole >3 sec), with or without vasodepression (drop in BP >50 mmHg), plus reproducibility of symptoms with carotid sinus massage (CSM).
Results: Mean age was 69±10.7 years and 104 pts (75.4%) were men. Mean follow-up period was 4.9±4.4 years. Prior to PP implantation 123 (89.1%) pts had syncope and 15 (10.9%) had near-syncope. Twenty one (15.2%) pts had mixed HCS and 117 (84.8%) had pure cardioinhibitory HCS. Table tilt test (TTT) was performed in 93 pts (67.4%). It was negative in 66 (71.0%) pts, showed pure vasodepressor response in 18 (19.4%; 5 symptomatic) and mixed response in 9 (9.6%; 3 symptomatic). After PP implantation 115 (83.3%) pts had no further symptoms, 8 (5.8%) had minor symptoms and in 15 (10.9%) the symptoms remained unchanged. Among pts with symptoms recurrence, 8 (38.1%) had mixed HCS and 15 (12.8%) had pure cardioinhibitory HCS. In Cox regression univariate analysis older age [HR 1.96 (95%CI 1.38 –9.30)] and mixed HCS [HR 4.19 (95%CI 1.48 –11.70)] were predictors of symptoms recurrence. In multivariate analysis only mixed HCS remained predictor of symptoms recurrence [HR 1.84 (95%CI 1.01–3.35)]. The PP mode and TTT result were not related to symptoms recurrence. However, pts who had mixed HCS were more likely to present a vasodepressor response (61.9% vs 19.4%; p<0,001) and to have symptoms (28,6% vs 2,8%; p= 0,001) on TTT.
Conclusions: Symptoms recurrence rate after PP implantation for pts with pure cardioinhibitory or mixed HCS was lower than previously reported. Mixed HCS was the only predictor of symptoms recurrence, probably due to the vasodepressor component persistence. The more frequent positive TTT results in pts with mixed HCS raises the hypothese that HCS and neurocardiogenic syncopes may have some common mechanisms.