[Diastolic murmur in non-obstructive hypertrophic cardiomyopathy].

Diastolic murmur (DM) in patients with non-obstructive hypertrophic cardiomyopathy (non-obst HCM) was studied regarding incidence, phonocardiographic disposition, mechanism, and also clinical characteristics of patients with DM. The results were as follows: 1) DM was recorded in 17 of 115 patients with non-obst HCM (15%), and was classified into three types of a mid-diastolic murmur, presystolic murmur, presystolic murmur and these combination. Mid-diastolic murmur showed low-pitched character mimicking a flow rumble around apical area in most patients. On the other hand, a presystolic murmur was relatively medium-pitched and spindle-shaped over the 4th left sternal border. Additionally, there were 7 patients of mitral opening sound coincided with the "O" point of the apex cardiogram, and 3 patients of an undefined sound or vibration during atrial contraction. 2) Impaired left ventricular (LV) compliance by pressure-volume analysis and decreased diastolic descent rate (DDR) in the mitral echocardiogram observed in patients with DM suggested that mechanism of these DM is mainly attributed to the disturbance of LV filling. Furthermore, mitral regurgitation was detected by LV angiography in a half of patients, indicating that DM might be partially related to increased mitral flow. 3) Clinically, DM was more common in younger patients of familiar occurrence and death, and with impaired physical work capacity. Therefore, auscultatory or phonocardiographic assessment of DM was clinically useful in the evaluation of patients with non-obst HCM.