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Echocardiographic assessment of the effect of an antihypertensive regimen on left ventricular performance
Insights
This study shows a three-drug regimen of chlorthalidone, hydralazine, and propranolol effectively lowers blood pressure in hypertensive patients. Propranolol neutralizes hydralazine
Area of Science:
- Cardiology
- Pharmacology
- Hypertension Management
Background:
- Hypertensive patients with coronary artery disease or aortic dissection require careful treatment.
- Hydralazine can cause reflex cardiac stimulation, potentially worsening outcomes.
- Propranolol's ability to counteract this stimulation is crucial for combination therapy.
Purpose of the Study:
- To evaluate the efficacy and safety of a three-drug regimen (chlorthalidone, hydralazine, propranolol) for hypertension.
- To determine if propranolol neutralizes hydralazine-induced reflex cardiac stimulation.
- To assess the impact on blood pressure, heart rate, cardiac contractility, and plasma renin activity.
Main Methods:
- A prospective study involving nine hypertensive patients.
- Sequential treatment over three weeks: chlorthalidone alone, then with hydralazine, and finally with hydralazine and propranolol.
- Weekly measurements of blood pressure, heart rate, echocardiographic VCF, and plasma renin activity.
Main Results:
- The three-drug regimen significantly reduced mean blood pressure from 142 to 102 mm Hg.
- Propranolol normalized elevated heart rate, VCF, and plasma renin activity induced by chlorthalidone and hydralazine.
- Left ventricular contractility (VCF) correlated with the rate of aortic pressure rise (dP/dt).
Conclusions:
- The combination of chlorthalidone, hydralazine, and propranolol is a potent antihypertensive regimen.
- Propranolol effectively counteracts the adverse cardiac effects of hydralazine in this context.
- This regimen appears safe for hypertensive patients with ischemic heart disease and aortic dissection.
Abstract:
A regimen consisting of chlorthalidone, hydralazine and propranolol would be useful in some hypertensive patients with coronary artery disease or aortic dissection if it could be shown that reflex cardiac stimulation induced by hydralazine is completely neutralized by propranolol. Nine hypertensive patients were treated with chlorthalidone during week 1, chlorthalidone and hydralazine during week 2 and a combination of chlorthalidone, hydralazine and propranolol during week 3. Blood pressure, heart rate, mean velocity of circumferential fiber shortening (VCF) measured echocardiographically and plasma renin activity were measured weekly. This potent three drug regimen reduced mean blood pressure from 142 to 102 mm Hg, and with the third drug, propranolol, heart rate, VCF and plasma renin activity returned to control levels from the greater elevated levels produced by the diuretic drug and hydralazine. In six additional patients VCF (an index of left ventricular contractility) was found to be proportionate to the rate of rise of aortic pressure (dP/dt) or aortic shearing force. This regimen appears safe for use in patients with ischemic heart disease and aortic dissection.