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Cardiac and haemodynamic effects of enalapril
Insights
Enalapril reduces peripheral resistance and left ventricular hypertrophy in hypertensive patients by inhibiting angiotensin II generation. Its hemodynamic effects are consistent with other ACE inhibitors, preserving cardiac function.
Area of Science:
- Cardiology
- Pharmacology
- Nephrology
Background:
- Hypertension is a major risk factor for cardiovascular disease.
- Angiotensin II plays a key role in regulating blood pressure and cardiac remodeling.
- Angiotensin-converting enzyme (ACE) inhibitors are a cornerstone in hypertension management.
Purpose of the Study:
- To evaluate the hemodynamic effects of enalapril in patients.
- To assess the impact of enalapril on left ventricular hypertrophy.
- To elucidate the mechanism of action of enalapril.
Main Methods:
- Sequential radionuclide studies in 10 patients.
- Echocardiographic assessment of left ventricular structure and function.
- Hemodynamic and neurohumoral response evaluation during upright tilt.
Main Results:
- Enalapril reduced peripheral resistance without significant changes in cardiac output or heart rate.
- Minimal changes in blood volume were observed.
- Significant regression of left ventricular hypertrophy occurred in hypertensive patients.
- Ventricular performance was preserved despite reduced ventricular mass.
Conclusions:
- Enalapril's hemodynamic effects stem from inhibiting angiotensin II generation.
- Enalapril effectively reduces left ventricular hypertrophy in hypertensive patients.
- Enalapril preserves cardiac function while managing hypertension.
Abstract:
The haemodynamic effects of enalapril were evaluated by sequential radionuclide studies in 10 patients followed for three to seven months. The pattern of response was remarkably similar to that of angiotensin antagonists and other oral converting enzyme inhibitors; it consisted of a reduction in peripheral resistance, minimal blood volume changes and no significant increase in either cardiac output or heart rate. The haemodynamic and neurohumoral responses to upright tilt remained normal, despite the lack of supine tachycardia in response to peripheral vasodilation. The pattern of response suggests that the haemodynamic effects of enalapril resulted from interference with angiotensin II (AII) generation rather than from a direct drug effect. Serial echocardiographic studies showed a significant regression in left ventricular (LV) hypertrophy in six out of seven hypertensive patients followed sequentially for three to seven months. Ventricular performance was well preserved despite the reduction in ventricular mass, as indicated by maintenance of the normal relationship of LV fractional shortening (% Sh) to LV end-systolic stress.