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Impaired left ventricular rapid filling during exercise in patients with hypertrophic cardiomyopathy
Insights
Patients with hypertrophic cardiomyopathy (HCM) show depressed diastolic reserve during exercise. This study found impaired left ventricular filling in HCM patients, suggesting factors beyond hypertrophy contribute to diastolic dysfunction.
Area of Science:
- Cardiology
- Exercise Physiology
Background:
- Hypertrophic cardiomyopathy (HCM) is a genetic heart condition characterized by abnormal thickening of the heart muscle.
- Diastolic dysfunction, impaired relaxation and filling of the left ventricle, is a common feature of HCM.
Purpose of the Study:
- To investigate the influence of dynamic exercise on left ventricular (LV) diastolic filling in patients with HCM compared to normal controls (NC).
- To assess whether LV hypertrophy correlates with diastolic abnormalities during exercise in HCM.
Main Methods:
- Dynamic exercise echocardiography was performed on 14 HCM patients and 14 NC.
- Normalized peak rate of change of LV dimension during systole (pVs) and rapid filling phase (pVd) were measured at rest and during exercise (heart rate ~100 beats/min).
- The ratio of pVd to pVs was calculated to assess diastolic reserve.
Main Results:
- pVs was significantly higher in HCM patients than NC at rest and during exercise.
- pVd was not significantly different between HCM patients and NC at rest or during exercise.
- The ratio of pVd/pVs significantly increased with exercise in NC but not in HCM patients, indicating reduced diastolic reserve in HCM.
- No correlation was found between pVd and the degree of LV hypertrophy.
Conclusions:
- Diastolic reserve to exercise is depressed in patients with hypertrophic cardiomyopathy.
- Factors other than left ventricular hypertrophy may contribute to the diastolic abnormalities observed in HCM during exercise.
Abstract:
The influence of exercise on left ventricular diastolic filling was evaluated in 14 patients with hypertrophic cardiomyopathy (HCM) and 14 normal controls (NC) by dynamic exercise echocardiography. Using X-Y digitizer and computer, normalized peak rate of change of the left ventricular dimension during systole (pVs) and the rapid filling phase (pVd) were determined from the left ventricular echocardiograms at rest and during exercise when heart rate reached 100 beats/min. At rest and during exercise, pVs was significantly higher in HCM (3.2 +/- 0.4/s at rest, 4.3 +/- 1.4/s during exercise) than in NC (2.4 +/- 0.5/s at rest, 3.0 +/- 0.4s during exercise) (p less than 0.001, p less than 0.001, respectively), but pVd in HCM (4.2 +/- 1.0/s at rest, 5.8 +/- 1.0/s during exercise) was not significantly different from that in NC (4.1 +/- 1.0/s at rest, 6.0 +/- 0.7/s during exercise). The ratio of pVd to pVs (pVd/pVs) in HCM did not show significant increment during exercise (1.35 +/- 0.38 to 1.43 +/- 0.35), though that ratio in NC was significantly increased by exercise (1.67 +/- 0.22/s to 1.97 +/- 0.19/s, p less than 0.001). There was no correlation between pVd and the degree of left ventricular hypertrophy. These results suggest that diastolic reserve to exercise is depressed in HCM and that other factors besides left ventricular hypertrophy may account for diastolic abnormality.