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Comparative effects of verapamil and nitroprusside on left ventricular function in patients with hypertension
J E Brush1, J E Udelson, S L Bacharach
1Cardiology Branch, National Heart, Lung, and Blood Institute, Bethesda, Maryland.
Insights
Verapamil increased left ventricular end-diastolic volume without reducing ejection fraction, unlike nitroprusside. This study compares verapamil and nitroprusside effects on cardiac function in hypertensive patients.
Area of Science:
- Cardiology
- Pharmacology
Background:
- Hypertension management during cardiac catheterization requires careful drug selection.
- Verapamil and nitroprusside have distinct hemodynamic profiles.
- Assessing left ventricular pressure-volume relations is crucial for understanding drug effects.
Purpose of the Study:
- To compare the hemodynamic effects of verapamil and nitroprusside in hypertensive patients undergoing cardiac catheterization.
- To evaluate the impact of these drugs on left ventricular function and systemic vascular resistance.
Main Methods:
- 10 symptomatic hypertensive patients undergoing cardiac catheterization.
- Matched mean arterial pressures and heart rates were maintained.
- Simultaneous radionuclide angiography and micromanometer pressure measurements were used.
- Left ventricular pressure-volume relations were assessed.
Main Results:
- Verapamil increased left ventricular end-diastolic volume index without significantly altering ejection fraction or cardiac index.
- Verapamil decreased systemic vascular resistance index.
- Nitroprusside decreased left ventricular end-diastolic volume index, cardiac index, and stroke volume index, with no change in systemic vascular resistance.
Conclusions:
- Verapamil demonstrates a favorable hemodynamic profile in hypertensive patients during cardiac catheterization, increasing preload without compromising systolic function.
- Nitroprusside's effects are characterized by preload reduction and decreased cardiac output.
- These findings highlight differential effects of verapamil and nitroprusside on cardiac hemodynamics.
Abstract:
The effects of verapamil were compared with those of nitroprusside at matched mean arterial pressures and heart rates in 10 symptomatic hypertensive patients during cardiac catheterization. Simultaneous radionuclide angiography and micromanometer pressure measurements were obtained to assess left ventricular pressure-volume relations. Compared with control conditions, verapamil increased left ventricular end-diastolic volume index from 57 +/- 16 to 70 +/- 28 ml/m2 (p = 0.05) without a significant increase in left ventricular end-diastolic pressure (from 10 +/- 4 to 13 +/- 6 mm Hg). Despite a downward and rightward shift in the end-systolic pressure-volume relation indicating negative inotropic effects, ejection fraction did not decrease significantly (from 52 +/- 9% to 46 +/- 9%); cardiac index and stroke volume index remained unchanged. The change in stroke volume index with verapamil was directly related to the magnitude of change in end-diastolic volume index (r = 0.82, p less than 0.005), suggesting that the increase in end-diastolic volume did not arise purely from negative inotropic effects. Systemic vascular resistance index decreased from 42 +/- 8 to 34 +/- 7 mm Hg.min.m2/liter (p less than 0.05). In contrast, nitroprusside decreased left ventricular end-diastolic volume index from 57 +/- 16 to 41 +/- 10 ml/m2 (p less than 0.05), cardiac index from 3.2 +/- 0.7 to 2.8 +/- 0.6 liters/min per m2 (p less than 0.05) and stroke volume index from 28 +/- 6 to 24 +/- 5 ml/m2 (p less than 0.01), with no change in systemic vascular resistance index (40 +/- 10 mm Hg.min.m2).(ABSTRACT TRUNCATED AT 250 WORDS)