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Cardiac mass and aortic distensibility following calcium blockade in hypertension
M E Safar1, B P Pannier, P J Lacolley
1Department of Internal Medicine, Broussais Hospital, Paris, France.
Insights
Verapamil effectively lowers blood pressure in hypertension patients. This calcium channel blocker reduces cardiac output and heart rate with minimal impact on cardiac performance and arterial structure.
Area of Science:
- Cardiology
- Pharmacology
- Hypertension Research
Background:
- Essential hypertension is a widespread condition requiring effective treatment.
- Calcium channel blockers, like verapamil, are commonly used antihypertensive agents.
- Understanding the impact of verapamil on cardiac and vascular function is crucial for optimizing treatment.
Purpose of the Study:
- To investigate the effects of verapamil on cardiac structure and function, and vascular properties in patients with sustained essential hypertension.
- To assess whether verapamil's blood pressure-lowering effect is associated with significant changes in cardiac performance or arterial stiffness.
Main Methods:
- Utilized noninvasive echo-Doppler methods to assess cardiac structure, function, and maximum aortic acceleration.
- Measured carotid-femoral pulse-wave velocity to evaluate arterial properties.
- Conducted measurements at baseline, after 12 weeks of verapamil treatment, and after a 4-week placebo period.
Main Results:
- Verapamil significantly reduced blood pressure (p < 0.001), cardiac output (p < 0.05), and heart rate (p < 0.002).
- No significant changes were observed in maximum aortic acceleration or the relationship between fractional shortening and end-systolic stress, indicating preserved cardiac performance.
- Cardiac mass decreased by approximately 6.3%, while pulse-wave velocity remained unchanged, suggesting limited impact on vascular impedance.
Conclusions:
- Verapamil demonstrates an antihypertensive effect with minimal alterations in cardiac performance and arterial structure.
- The observed decrease in cardiac mass may not directly translate to improved vascular capacitance.
- Calcium blockade by verapamil achieves blood pressure reduction independently of significant changes in cardiac and arterial hemodynamics.
Abstract:
Calcium-entry blockade produced by verapamil was studied in 13 subjects with sustained essential hypertension. Noninvasive echo-Doppler methods were used to evaluate cardiac structure and function, maximum aortic acceleration (used as an indirect index of cardiac performance), and carotid-femoral pulse-wave velocity. Measurements were performed in baseline conditions, following 12 weeks of active treatment, and 4 weeks of placebo. Following verapamil, blood pressure (BP) significantly decreased (p less than 0.001) with a slight reduction in cardiac output (p less than 0.05) and a more substantial decrease in heart rate (p less than 0.002). No significant change occurred in maximum acceleration and in the curve relating percent fractional shortening to end-systolic stress, suggesting that verapamil decreased BP with minor changes in cardiac performance. Cardiac mass decreased by approximately 6.3% whereas pulse-wave velocity did not change, suggesting that the small decrease in cardiac mass could be related to the lack of improvement in the capacitative component of vascular impedance, as judged from the determination of pulse-wave velocity. The study provides evidence that calcium blockade due to verapamil results in a dissociation between the antihypertensive effect and the absence of significant changes in cardiac and arterial structure and function.