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[Differences in left ventricular systolic performance during exercise in patients with hypertrophic cardiomyopathy
Insights
Hypertrophic cardiomyopathy (HCM) patients show impaired left ventricular systolic performance during exercise compared to healthy individuals and those with hypertension (HT). HCM patients exhibit unchanged end-systolic dimensions and no increase in shortening fraction with exercise.
Area of Science:
- Cardiology
- Cardiovascular Physiology
- Diagnostic Imaging
Context:
- Hypertrophic cardiomyopathy (HCM) and systemic hypertension (HT) can affect left ventricular (LV) function.
- Exercise echocardiography is a valuable tool for assessing cardiac performance under stress.
- Comparing LV systolic performance in HCM and HT with normal subjects provides insight into disease-specific adaptations.
Purpose:
- To evaluate differences in global and regional systolic performance of the left ventricle during submaximal exercise in patients with HCM and HT.
- To compare these performances with those of normal subjects.
Summary:
- Multi-stage submaximal exercise echocardiography was performed on 21 HCM patients, 14 HT patients, and 18 normal subjects with similar interventricular septal thickness.
- Unlike HT and normal groups, HCM patients did not show a decrease in end-systolic dimension or an increase in % shortening fraction during exercise.
- Systolic wall thickening of the interventricular septum and left ventricular posterior wall increased in HT patients but remained unchanged in HCM patients during exercise.
Impact:
- This study highlights distinct patterns of left ventricular systolic dysfunction during exercise in hypertrophic cardiomyopathy.
- Findings suggest that HCM impairs the heart's ability to increase contractility and optimize dimensions under stress.
- Understanding these differences is crucial for accurate diagnosis and management of cardiovascular conditions.
Abstract:
To evaluate differences in systolic global and regional performances of the left ventricle during exercise, multi-stage submaximal exercise echocardiography was used for 21 patients with hypertrophic cardiomyopathy (HCM) and 14 patients with systemic hypertension (HT), whose interventricular septa (IVS) were nearly the same in thickness (HCM; 16.5 +/- 2.4 mm, HT; 15.4 +/- 1.7 mm, NS). The data were compared with those of 18 normal subjects (N). During exercise, end-diastolic dimension (EDD) was increased in all three groups; however, there was no statistical differences among the three groups either at rest or during exercise. End-systolic dimension (ESD) was significantly decreased during exercise in HT (29.3 +/- 5.8 at rest to 28.1 +/- 5.8 mm at the peak exercise, p less than 0.05) and N (from 30.3 +/- 3.3 to 25.7 +/- 3.0 mm, p less than 0.001). On the other hand, ESD of HCM at rest, which was less than those of the other two groups, did not decrease with exercise (from 25.1 +/- 4.5 to 25.6 +/- 4.6 mm, NS), and rather they increased (more than 2 mm) during exercise in seven patients. The % shortening fraction (%SF) increased from rest to exercise both in HT (35.6 +/- 7.9% to 40.1 +/- 9.6%, p less than 0.001) and in N (from 35.1 +/- 4.2 to 45.9 +/- 4.7%, p less than 0.001). However, in the HCM group, the %SF, which was significantly greater at rest than in the other two groups, did not increase during exercise (42.5 +/- 6.8 to 42.5 +/- 8.8%, NS). In addition, in seven of 21 patients with HCM, the %SF increased more than 5% at the peak exercise. At rest, systolic wall thickening (%WT) of the IVS equally reduced both in HCM and HT. It increased in HT from 20.8 +/- 9.3% at rest to 24.6 +/- 12.7% at the peak exercise (p less than 0.05), but did not change in HCM (from 16.6 +/- 9.6% to 16.3 +/- 7.0%, NS). At rest, %WT of the left ventricular posterior wall (LVPW) was significantly greater in HCM than in HT. During exercise, it increased in HT (from 43.1 +/- 15.9% to 61.9 +/- 20.5%, p less than 0.01), but did not increase in HCM (from 81.0 +/- 27.7% to 85.5 +/- 29.6%, NS).(ABSTRACT TRUNCATED AT 400 WORDS)