Maximum stress‐volume index ratio of the left ventricle in hypertrophic cardiomyopathy

To evaluate the left ventricular contractile state in patients with nonobstructive hyper‐trophic cardiomyopathy (HCM), we analyzed the maximum stress‐volume index ratio (MSVR) using catheter‐tip cineangiography in 11 patients with HCM and 16 normal subjects. The value of the MSVR in normal subjects was 6.48±1.25 kdyn/cm 5 /m 2 (mean±SD) and we defined the range of the mean±2 SD as the normal MSVR range. Six patients with HCM placed inside the normal MSVR range (IN), but the other 5 patients placed outside and to the right of the normal range (RIGHT). This suggests that the contractile states of the patients of the RIGHT group were depressed. Compared with IN, the end‐diastolic and end‐systolic volume Indices of RIGHT were larger (EDVI; 69.3±6.9 vs. 96.1 ±11.1 ml/m 2 , p <0.01, ESVI; 18.2 ± 3.2 vs. 29.1 ±8.3 ml/m 2 , p <0.05), but the ejection fraction did not differ (IN 73.5±5.7 vs. RIGHT 69.6±8.3%, NS). End‐diastolic pressure of IN and RIGHT was higher than that of normal subjects (IN 16.5±4.5, RIGHT 16.7±4.6 vs. 8.3±2.5 mm Hg, both p <0.05), but there was no difference between the two groups in HCM. End‐systolic pressure did not differ among the three groups. End‐diastolic, mean systolic, and end‐systolic stresses of IN were similar to those of RIGHT Left ventricular wall thickness (RIGHT 1.66±0.22 vs. IN 1.36±0.14 cm, p <0.05) and mass index (RIGHT 272.2±25.5 vs. IN 176.1 ±19.0 g/m 2 , p <0.01) of RIGHT were larger than those of IN. Furthermore, there were linear inverse relations between the MSVR and the end‐diastolic volume index ( r = −0.84) and between the MSVR and mass index ( r =‐0.91) in the 11 patients with HCM. These results suggest that there were two groups among the HCM patients, that is, those with normal (or preserved) and those with depressed contractile states, and patients with large end‐diastolic volume indices and increased mass indices tended to have depressed contractile states.