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Impaired left ventricular functional reserve in hypertensive patients with left ventricular hypertrophy
J F Tubau1, J Szlachcic, S Braun
1Department of Medicine, University of California, San Francisco.
Insights
Hypertensive patients with left ventricular hypertrophy show abnormal cardiac function during exercise, even with normal resting ejection fraction. This dysfunction may indicate a higher risk for heart failure development.
Area of Science:
- Cardiology
- Cardiovascular Physiology
Background:
- Hypertension is a major risk factor for cardiovascular disease.
- Left ventricular hypertrophy (LVH) is a common adaptation to chronic hypertension.
- Subtle changes in cardiac function in hypertensive patients with LVH require further investigation.
Purpose of the Study:
- To investigate cardiac functional responses to exercise in hypertensive patients, particularly those with left ventricular hypertrophy (LVH).
- To assess if LVH in hypertensive patients is associated with altered ventricular performance during physical stress.
Main Methods:
- Echocardiography was used to assess left ventricular hypertrophy (LVH).
- Cardiac function was evaluated by measuring changes in left ventricular ejection fraction and systolic blood pressure to end-systolic volume index during exercise.
- 40 hypertensive patients and 16 normotensive controls were studied.
Main Results:
- Hypertensive patients with LVH exhibited increased resting end-systolic wall stress compared to controls.
- The increase in ejection fraction with exercise was significantly lower in patients with LVH.
- Hypertensive patients with LVH showed reduced systolic blood pressure to end-systolic volume index changes during exercise, indicating impaired ventricular function.
Conclusions:
- Hypertensive patients with LVH and normal resting ejection fraction demonstrate abnormal cardiac functional responses to exercise.
- These exercise-induced functional abnormalities may identify patients at increased risk for future heart failure.
- Echocardiographic assessment of LVH is crucial for identifying hypertensive patients with subtle cardiac dysfunction.
Abstract:
To determine whether patients with hypertension and especially those with left ventricular hypertrophy have subtle changes in cardiac function, we measured the increase in left ventricular ejection fraction and in systolic blood pressure to end-systolic volume index ratio with exercise in 40 hypertensive patients and 16 age-matched normotensive volunteers. Twenty-two hypertensive patients without hypertrophy had normal end-systolic wall stress at rest and exercise responses. In contrast, the 18 patients with echocardiographic criteria for left ventricular hypertrophy demonstrated a significant increase in end-systolic wall stress at rest compared with normal subjects (69 +/- 16 vs. 55 +/- 15 10(3) x dyne/cm2, p less than 0.05) despite having normal resting left ventricular size and ejection fraction. In patients with left ventricular hypertrophy, the increase in ejection fraction with exercise was less than in the normotensive control subjects (7 +/- 7 vs. 12 +/- 8 units, p less than 0.05), and delta systolic blood pressure to end-systolic volume with exercise was reduced (3.3 +/- 3.8 vs. 8.3 +/- 7.7 mm Hg/ml/m2, p less than 0.05). The hypertensive patients with hypertrophy displayed a shift downward and to the right in the relation between systolic blood pressure to end-systolic volume ratio and end-systolic wall stress compared with control subjects and hypertensive patients without left ventricular hypertrophy. Thus, hypertensive patients with left ventricular hypertrophy by echocardiography and normal resting ejection fraction exhibit abnormal ventricular functional responses to exercise. This finding may have implications in identifying patients at higher risk for developing heart failure.