Coronary hemodynamics in patients with symptomatic hypertrophic cardiomyopathy

The purpose of this study was to analyze coronary hemodynamics and determine a possible mechanism for microvascular dysfunction in patients with symptomatic hypertrophic cardiomyopathy (HC). Although patients with HC have been shown to have microvascular dysfunction and reduced coronary flow reserve (CFR), the mechanism by which this occurs is not well understood. We studied coronary hemodynamics in 8 patients with symptomatic HC and compared them with 8 matched controls. Compared with controls, patients with HC had higher coronary blood flow, lower coronary resistance, and lower CFR. Patients with HC also had abnormal phasic coronary flow characteristics. These results suggest that the reduction of CFR in patients with HC may be secondary to near maximal vasodilation of the microcirculation in the basal state.