Circadian Variation of Beat‐to‐Beat QT Interval Variability in Patients with Prior Myocardial Infarction and the Effect of β‐Blocker Therapy

Abstract

These data indicate that the QTV increases during the daytime in patients with MI and that this circadian effect is prevented by beta-blocker therapy. Thus, beta-blocker therapy may reverse the maladaptation of the ventricular repolarization to the change in the heart rate and may thereby reduce the ventricular arrhythmias and decrease the mortality in patients with MI.