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Haemodynamic effects of diltiazem at rest and during exercise in patients with previous myocardial infarction
F Cobelli1, C Opasich, G Riccardi
1Fondazione Clinica del Lavoro di Pavia (IRCCS), Italy.
Insights
Intravenous diltiazem reduced afterload and preload in male patients post-myocardial infarction. This cardiovascular drug decreased blood pressure and myocardial oxygen consumption without significantly increasing cardiac index.
Area of Science:
- Cardiology
- Pharmacology
Background:
- Patients with previous myocardial infarction often experience altered hemodynamics.
- Exertional ischemia is a concern in post-myocardial infarction patients.
Purpose of the Study:
- To evaluate the hemodynamic effects of intravenous diltiazem in male patients with prior myocardial infarction.
- To assess the impact of diltiazem on cardiovascular parameters during rest and exercise.
Main Methods:
- A single-blind study comparing placebo and intravenous diltiazem (25 mg) in 20 male patients.
- Hemodynamic variables were measured using right heart and arterial catheterization at rest and during graded exercise.
- Diltiazem or placebo was administered before the second exercise test.
Main Results:
- Diltiazem significantly reduced resting blood pressure and systemic vascular resistance, while increasing cardiac index compared to placebo.
- During exercise, diltiazem lowered pulmonary arterial pressure, pulmonary wedge pressure, and total pulmonary resistance.
- Diltiazem decreased myocardial oxygen consumption and blood pressure, with a slight reduction in heart rate and right atrial pressure.
Conclusions:
- Intravenous diltiazem effectively reduces afterload and preload in patients post-myocardial infarction.
- Diltiazem demonstrates beneficial hemodynamic effects during exercise, including reduced pulmonary pressures.
- The drug decreases myocardial oxygen demand and improves cardiovascular parameters without significantly impairing cardiac output.
Abstract:
A single blind study between placebo and diltiazem (25 mg i.v. single dose) was carried out on 20 male patients with previous myocardial infarction and without exertional ischaemia. Patients, 50 +/- 6.1 (mean +/- SD) years of age, underwent a right heart catheterization with Seldinger's percutaneous approach and brachial or radial artery percutaneous catheterization. Haemodynamic variables were recorded in the supine position after catheterization in baseline conditions at rest, after a warming-up period of 6 min, before and after a first and second exercise test with stepwise increments of 25 W per 3 min. Before the second exercise test, either placebo or diltiazem (25 mg) was injected intravenously in 3 min. In comparison with placebo, diltiazem significantly reduced resting blood pressure (P less than 0.001) and systemic vascular resistance (P less than 0.001) and increased cardiac index (P less than 0.01); during exercise it also reduced the mean pulmonary arterial pressure (P less than 0.05), pulmonary wedge pressure (P less than 0.05), total pulmonary resistance (P less than 0.02), and increased the stroke volume (P less than 0.05). The present study demonstrated that intravenous diltiazem did not induce a significant rise in cardiac index but reduced the afterload and slightly reduced the preload. Diltiazem also reduced myocardial oxygen consumption and decreased blood pressure, mean right atrial pressure and slightly decreased the heart rate.
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