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Exercise induces cardiac dysfunction in both moderate, compensated and severe hypertrophy
L Hittinger1, T Patrick, T Ihara
1Department of Medicine, Harvard Medical School, Brigham and Women's Hospital, Boston, Mass.
Circulation
|May 1, 1994
Summary
Severe left ventricular hypertrophy (LVH) impairs cardiac function during exercise, even when moderate. This study shows that significant LVH with elevated wall stress leads to abnormal responses to exercise, affecting blood flow and function.
Area of Science:
- Cardiology
- Physiology
Background:
- Ventricular hypertrophy initially adapts to cardiac overload but can become pathological.
- The impact of hypertrophy extent on exercise response requires further investigation.
Purpose of the Study:
- To examine how the degree of left ventricular (LV) hypertrophy influences cardiac function and myocardial blood flow during exercise.
- To compare exercise responses in dogs with moderate and severe LV hypertrophy.
Main Methods:
- Left ventricular hypertrophy was induced in puppies via aortic banding.
- Exercise responses (hemodynamics, LV function, blood flow) were compared between control dogs and those with moderate or severe LV hypertrophy.
Main Results:
- Moderate LV hypertrophy showed similar exercise responses to controls, but impaired contraction-afterload relations.
- Severe LV hypertrophy led to reduced cardiac function, decreased blood pressure, and a fall in endocardial/epicardial blood flow ratio during exercise.
- Subgroup analysis of severe LV hypertrophy did not reveal significant differences, but overall function was more impaired than in moderate hypertrophy.
Conclusions:
- Severe LV hypertrophy with elevated wall stress causes abnormal exercise responses in global and regional function and blood flow.
- Qualitatively impaired contraction-afterload relations were observed even in moderately hypertrophied, compensated hearts during exercise stress.