Session P71.2

Circadian Variation in the Occurrences of Ventricular Tachyarrhythmias: Differences between Coronary Artery Disease and Dilated Cardiomyopathy

A Casaleggio*, P Rossi, V Malavasi, G Musso, L Oltrona

CNR Institute of Biophysics
Genova, Italy

Aim: This retrospective study investigates circadian variation of ventricular tachyarrhythmias (VT) in patients with an implantable cardioverter defibrillator (ICD). In particular differences between patients with coronary artery disease (CAD) or dilated cardiomyopathy (DCM) are evaluated.
Methods: The circadian variation of VT recorded by an ICD was studied in 37 patients that received an ICD as secondary prevention between 1998 and 2002. Follow-up continued until the end of 2005. In this study are included all the VT (treated and self-terminating) recorded in far-field mode. CAD population consisted of 26 subjects (23 males and 3 females), age 69 +/- 9 years, ejection fraction 35 +/- 7%, and follow-up 34 +/- 11 months; DCM group contained 11 subjects (10 males and 1 female), age 67 +/-10 years, ejection fraction 33 +/- 8%, and follow-up 27 +/-12 months. The times of VT episode were retrieved from the data log of each ICD device. When more than a single VT episodes was collected from the same patients, the corresponding weight was normalized.
Results: 165 VT episodes (40 self-terminated and 125 treated by the ICD) were recorded in the 37 patients: 79 were collected from CAD and 86 from DCM population. Circadian variation of VT episodes from CAD group showed a clear peak in the morning (22% of episodes occurred between 8 and 12 AM) and afternoon (30% of episodes occurred between 4 and 8 PM); DCM group showed a different pattern without clear peaks in the morning and afternoon, but is observed a concentration of VT episodes during day light hours (between 8 AM and 8 PM are counted the 80% of VT-episodes). Seven out of 37 patients (2 with CAD and 5 with DCM) experienced more than 7 episodes of VT, showing a pattern distributed all along the daylight hours, probably related to emotional stress.
Conclusion: CAD and DCM patients show different patterns of circadian variation in the occurrences of VT episodes.

(Abstract Control Number: 117)