Abstract 17451: Circadian Rhythm Variation of Malignant Ventricular Arrhythmias and Its Relation to Mortality Among Patients With Mild Heart Failure
Background: Little is known about circadian variation of malignant ventricular tachyarrhythmias (VTA) in mildly symptomatic heart failure patients with implantable cardioverter-defibrillator (ICD) or cardiac resynchronization therapy (CRT-D) devices. Furthermore it is unknown whether there are differences in circadian variation of VTAs and if it would affect the outcome.
Methods: A total of 1790 patients (males 75.2%) with heart failure, NYHA class I and II and implanted CRT-D or ICD from the MADIT-CRT study were included. Time of first an all VTAs as detected and treated by the device with appropriate ICD therapy was evaluated by hours and weekdays and related to all-cause mortality using Cox regression analyses.
Results: During a mean follow-up period of 40 months, a total of 3300 VTA episodes were registered. Of all VTAs recorded, most of them (n=2977, 90%) occurred in men. Recurrent as well as first VTA episodes were more common in the morning and afternoon with bimodal peaks from 7-11 AM (24.3%) and 5-9 PM (18.4%) (Figure). A total of 856 VTAs (26%) occurred during nighttime or potential sleeping hours (11 PM to 6.59 AM). The VTAs were unevenly distributed across weekdays with the greatest proportion (17%) on Mondays versus the lowest proportion on Sundays (11%).
VTAs that occurred during morning hours (7-11 AM) were associated with higher mortality when compared to VTA episodes occurring at other hours (HR=2.02, CI: 1.15-3.54, p=0.014).
Conclusion: The occurrence of ventricular arrhythmias among mildly symptomatic heart failure patients exhibit circadian variations with highest incidence during daily periods with possible higher sympathetic tone that translates into a higher risk of all-cause mortality.
- © 2013 by American Heart Association, Inc.