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Adrenergic activity and left ventricular function during treatment of essential hypertension with calcium antagonists
Insights
Verapamil effectively lowered blood pressure without altering heart rate or catecholamines. Nifedipine also reduced blood pressure but increased heart rate and catecholamines in hypertensive patients.
Area of Science:
- Cardiology
- Pharmacology
- Hypertension Research
Background:
- Essential hypertension is a prevalent cardiovascular condition.
- Calcium channel blockers are widely used antihypertensive agents.
- Understanding the differential effects of verapamil and nifedipine is crucial for clinical practice.
Purpose of the Study:
- To compare the effects of verapamil and nifedipine on hemodynamic and neurohormonal parameters in patients with essential hypertension.
- To assess the impact of these drugs on left ventricular anatomy and function.
Main Methods:
- A study involving 67 patients with essential hypertension.
- Assessment of blood pressure, heart rate, plasma catecholamines, and plasma renin activity.
- Echocardiographic evaluation of left ventricular parameters.
- A crossover comparison in 12 hospitalized patients.
Main Results:
- Verapamil demonstrated antihypertensive effects without significant changes in heart rate, plasma catecholamines, or plasma renin activity.
- Nifedipine lowered blood pressure, accompanied by significant increases in heart rate and plasma catecholamines.
- Both verapamil and nifedipine significantly decreased left ventricular mass after 3 months of treatment.
- Nifedipine treatment led to slight but significant increases in stroke volume and shortening fraction.
Conclusions:
- Verapamil offers an antihypertensive effect with minimal impact on sympathetic activity.
- Nifedipine's blood pressure reduction is associated with increased sympathetic drive.
- Both verapamil and nifedipine can beneficially remodel the left ventricle in hypertensive patients.
Abstract:
The effects of 2 calcium antagonist drugs, verapamil and nifedipine, on blood pressure, heart rate (HR), plasma catecholamines, plasma renin activity and some echocardiographic indexes of left ventricular anatomy and function were studied in 67 patients with essential hypertension. The short- and long-term antihypertensive effect of verapamil was not associated with significant changes in HR, plasma catecholamines or plasma renin activity; the decrease in blood pressure after nifedipine was associated with a significant increase in HR and plasma catecholamines (mainly noradrenaline) (p less than or equal to 0.05). These findings were confirmed in a crossover comparison in 12 hospitalized patients treated with verapamil and nifedipine for 8 days each. The dose of isoproterenol that increased HR by 25 beats/min was significantly increased during verapamil treatment (p less than 0.05) and decreased during nifedipine treatment (p less than 0.01). Stroke volume and shortening fraction increased slightly but significantly (p less than 0.05) with 3 months of nifedipine treatment, while no change was detected with verapamil treatment. Left ventricular mass was significantly decreased after effective antihypertensive treatment for 3 months with verapamil or nifedipine (p less than or equal to 0.05).