Hemodynamic Determinants of Silent ST Segment Depression in Patients with Hypertrophic Cardiomyopathy Treated with Verapamil

Abstract

Objective: The aim of the study was to establish mechanisms of ischemic type, painless ST segment depression in nine patients with nonobstructive hypertrophic cardiomyopathy (HC) treated effectively by verapamil.Methods: Simultaneous 24-hour Holter and blood pressure monitoring (measurements every 15 minutes) was performed to determine approximate indices of myocardial oxygen demand (double product), myocardial oxygen supply (diastolic blood pressure), and ST segment level during each minute when blood pressure measurements were obtained. According to ST segment level, all recordings were divided into four subgroups (one without and three with gradually increasing magnitude of ST segment depression) in which average double product and diastolic blood pressure were calculated.Results: Increasing ST segment depression coincided with gradual rises in double product indicating increasing myocardial oxygen consumption. Diastolic blood pressure was low in the group without ST segment deviation whereas it was significantly higher only in groups with ST segment depression of more than 2 mm.Conclusion: Verapamil-induced, excessive fail of diastolic blood pressure was not associated with exacerbating ST segment depression. On the other hand, occasionally verapamil insufficiently prevented increases of double product, which coincided with the prescence of painless ST segment hypertrophic cardiomyopathy; painless myocardial ischemia; verapamil depression episodes.