Tian H, et al. - In this study performed on 53 hypertrophic obstructive cardiomyopathy (HOCM) patients, researchers investigated if an attenuation in microvascular density (MVD) was associated with myocardial fibrosis. They obtained myectomy left ventricular (LV) septal wall specimens and analyzed MVD and fibrosis. At autopsy of 9 individuals, in whom noncardiac causes resulted death, they collected myocardium from the LV septal wall as the control. A higher fibrosis ratio (% area), as well as a lower MVD, was detected in HOCM patients vs in controls. Findings revealed a negative correlation of the severity of myocardial fibrosis, with MVD in HOCM. The possible contribution of a reduced MVD to myocardial fibrosis was shown in HOCM.