Effects of propranolol on the QT dispersion in congestive heart failure

Abstract

Objective -Studies have shown that therapy with beta-blockers reduces mortality in patients with heart failure. However, there are no studies describing the effects of propranolol on the QT dispersion in this population. The objective of this study was to assess the electrophysiological profile, mainly QT dispersion, of patients with heart failure regularly using propranolol. Methods -Fifteen patients with heart failure and using propranolol were assessed over a period of 12 months. Twelve-lead electrocardiograms (ECG) were recorded prior to the onset of beta-blocker therapy and after 3 months of drug use.Results -A significant reduction in heart rate, in QT dispersion and in QTc dispersion was observed, as was also an increase in the PR interval and in the QT interval, after the use of propranolol in an average dosage of 100 mg/day. Conclusion -Reduction in QT dispersion in patientswith heart failure using propranolol may explain the reduction in the risk of sudden cardiac death with beta-blocker therapy, in this specific group of patients.

QT Intervals and QT Dispersion Determined from a 12‐Lead 24‐Hour Holter Recording in Patients with Coronary Artery Disease and Patients with Heart Failure

“…We observed that mean values of QT dispersion were increased in patients with heart failure compared with healthy subjects, which is in accordance with previous reports 8,25,26,27,28 . The larger mean values of QT dispersion could be a result of myocardial remodeling resulting in a slower and heterogeneous ventricular repolarization.…”

Beat‐to‐Beat QT Interval Variability Is Primarily Affected by the Autonomic Nervous System

“…Beta-blocker therapy improved survival and decreased sudden deaths in heart failure patients [13][14][15] by mechanisms that may include protection against catecholamines, antifibrillatory effects, minimizing hypokalemia and improvement in QT dispersion. [16][17][18][19] Berger et al demonstrated that patients with dilated cardiomyopathy had greater QT variance than control subjects despite reduced heart rate variance, and the QT interval variability increases with worsening New York Heart Association functional class but is independent of ejection fraction. 2 Atiga et al further demonstrated that QTVI could be used to identify patients with sudden cardiac death and to predict arrhythmiafree survival.…”

Effects of Carvedilol Therapy on Arrhythmia Markers in Patients With Congestive Heart Failure

“…23,24) A reduced QTd with beta-blockers other than carvedilol was also reported in patients with CHF. 8,25,26) Autonomic system integrity may be quantified noninvasively by analysis of HRV. 7) HRV is believed to mirror sympathovagal balance and has been shown to be decreased early after acute myocardial infarction, and the use of HRV by nominal 24-hour recordings is recommended for risk stratification.…”