CIRCADIAN VARIATION OF SUSTAINED VENTRICULAR TACHYARRHYTHMIAS TERMINATED BY APPROPRIATE SHOCKS IN PATIENTS WITH AN IMPLANTABLE CARDIOVERTER-DEFIBRILLATOR
S. Behrens et al., CIRCADIAN VARIATION OF SUSTAINED VENTRICULAR TACHYARRHYTHMIAS TERMINATED BY APPROPRIATE SHOCKS IN PATIENTS WITH AN IMPLANTABLE CARDIOVERTER-DEFIBRILLATOR, The American heart journal, 130(1), 1995, pp. 79-84
To determine the circadian variation of sustained ventricular tachyarr
hythmias, 78 consecutive patients with an implanted cardioverter defib
rillator were analyzed with regard to the occurrence of spontaneous sh
ock episodes during a mean follow-up period of 18 +/- 12 months. In 39
patients 207 shock episodes that terminated potentially life-threaten
ing ventricular tachyarrhythmias could be related to an exact time of
onset. A circadian variation (p < 0.001) of these events was demonstra
ted, with a primary morning peak between 7 hours and 11 hours and a se
condary, much smaller peak between 16 hours and 20 hours. This finding
indicates the relevance of endogeneous or exogeneous triggers in the
cause of malignant arrhythmias that potentially lead to sudden cardiac
death. Subgroup analyses revealed an association of the circadian pat
tern to the New York Heart Association functional classification, indi
cating perhaps a different role of triggers in different patient popul
ations.