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Maximum stress-volume index ratio of the left ventricle in hypertrophic cardiomyopathy
M Nakagawa1, K Shirato, M Sakuma
1Department of Internal Medicine, Tohoku University School of Medicine, Sendai, Japan.
Insights
Patients with nonobstructive hypertrophic cardiomyopathy (HCM) may have depressed left ventricular contractile function. The maximum stress-volume index ratio (MSVR) can help identify these patients.
Area of Science:
- Cardiology
- Cardiovascular Physiology
Background:
- Hypertrophic cardiomyopathy (HCM) is a genetic heart muscle disease.
- Assessing left ventricular (LV) contractile state is crucial for managing HCM.
- Nonobstructive HCM presents diagnostic challenges for LV function.
Purpose of the Study:
- To evaluate the left ventricular contractile state in patients with nonobstructive HCM.
- To determine if the maximum stress-volume index ratio (MSVR) can differentiate contractile function in HCM.
- To compare MSVR between HCM patients and healthy controls.
Main Methods:
- Utilized catheter-tip cineangiography to measure LV volumes and pressures.
- Calculated the maximum stress-volume index ratio (MSVR) in 11 HCM patients and 16 normal subjects.
- Defined a normal MSVR range based on mean +/- 2 standard deviations in controls.
Main Results:
- Six HCM patients had normal MSVR (IN), while 5 had depressed function (RIGHT).
- RIGHT group showed larger end-diastolic and end-systolic volumes (EDVI, ESVI) than IN group (p<0.01, p<0.05).
- Ejection fraction did not differ; end-diastolic pressures were elevated in both HCM groups compared to controls (p<0.05).
Conclusions:
- A subset of patients with nonobstructive HCM exhibits depressed LV contractile state.
- MSVR is a potential indicator for identifying impaired contractility in nonobstructive HCM.
- Further research is needed to understand the clinical implications of depressed contractility in HCM.
Abstract:
To evaluate the left ventricular contractile state in patients with nonobstructive hypertrophic 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/cm5/m2 (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/m2, p less than 0.01, ESVI; 18.2 +/- 3.2 vs. 29.1 +/- 8.3 ml/m2, p less than 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 less than 0.05), but there was no difference between the two groups in HCM. End-systolic pressure did not differ among the three groups.(ABSTRACT TRUNCATED AT 250 WORDS)