Abstract:

Background: Tilt testing (TT) and other evidence suggest that the vagal effect on the heart decreases with age.

Objective: The main aim of the study was to assess whether this age effect also affects the rate of asystole in spontaneous reflex syncope (RS).

Method: We performed an analysis of pooled individual data from 4 studies that recruited patients ≥ 40-year-old affected by certain or suspected RS who received an implantable loop recorder (ILR) and reported follow-up data on syncope recurrence. We assessed the presence of asystolic syncope >3 s or non-syncopal asystole > 6 s recorded by ILR and compared findings to TT results on the same patients.

Results: A total of 1046 patients received ILR due to unexplained syncope. Of these, 201 (19.2%) had a documentation of an asystolic event of 10 (IQR 6-15) s duration. They were subdivided in 3 age-tertiles: ≤ 60 years (n=64), 61-72 years (n=72) and ≥73 years (n=65). The rate of asystolic events was similar in the 3 subgroups (50.1%, 50.1% and 49.2% respectively, p=0.99). Conversely, the rate of asystolic syncope induced during TT (performed in 169/201) was greatly age-dependent (31.0%, 12.1% and 11.1% in increasing age-tertiles, respectively, p=0.009).

Conclusion: The rate of spontaneous asystolic form of RS documented by ILR is constant at any age > 40 years. Conversely, the rate of asystolic syncope induced by TT is higher in younger patients and decreases with ageing. The contrasting results between spontaneous and tilt-induced events cast doubt on the concept that asystole in RS is less common in older patients.

Editor-in-Chief
Kalyanam Shivkumar, MD, PhD, FACC
 
CME Editor
Kenneth A. Ellenbogen, MD, FACC

Author
Mahmoud Houmsse, MD, FACC

Important Dates
Date of Release: March 25, 2024
Term of Approval/Date of CME/MOC Expiration: March 24, 2025