Lack of Diurnal Variation of P-Wave and Qt Dispersions in Patients With Heart Failure

Abstract

Background: P-wave dispersion (PWD) is a new parameter for the assessment of risk of atrial fibrillation and has been reported to be increased in heart failure. Diurnal variation of the PWD has been reported in patients with coronary artery disease (CAD). QT dispersion (QTD) has also a circadian variation. In this study we aimed to search diurnal variation of PWD and QTD in patients with heart failure. Methods: Fifty-three clinical heart failure patients having left ventricular ejection fraction (LVEF) < 40% were divided into two groups according to presence of CAD. Twelve-lead ECGs were obtained in the morning (07:00-08:00 hours), at noon (12:00-14:00 hours), and at night (22:00-24:00 hours). Results: All the patients were in New York Heart Association class II except one in class I. beta-blocker and angiotensin-converting enzyme inhibitor or angiotensin receptor blocker usage was over 80% and spiranolactone usage was around 75% in the study group. PWD and QTD were not significantly different between patients with (n = 27) and without (n = 26) CAD. There was no significant diurnal variation of P wave and QT parameters. Conclusions: We found that PWD and QTD do not show diurnal variation in patients having either ischemic or nonischemic origin of heart failure treated with optimal drug therapy.