Effect of propranolol on circadian variation of myocardial ischemia in elderly patients with heart disease and complex ventricular arrhythmias

In our elderly population with prior myocardial infarction or hypertensive heart disease, complex ventricular arrhythmias, and an LV ejection fraction ≥40%, there was a circadian variation of the maximal amount of silent ischemia per hour in patients before and after no propranolol and before propranolol. The primary peak occurred between 8 and 9 A.M. before no propranolol, between 8 and 10 A.M. after no propranolol, and between 8 and 11 A.M. before propranolol. However, the circadian variation of the maximal amount of silent ischemia per hour was abolished by propranolol. Propranolol also abolished the circadian variation in sudden cardiac death or fatal myocardial infarction in these patients. This suggests that the sympathetic nervous system contributes to the circadian variation of silent ischemia as well as to the circadian variation of myocardial infarction or sudden cardiac death.