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Immediate haemodynamic effects of verapamil in man
Insights
Verapamil, an antiarrhythmic drug, temporarily lowers blood pressure and reduces left ventricular contractility in patients. Hemodynamic effects were similar across different patient groups.
Area of Science:
- Cardiology
- Pharmacology
Background:
- Verapamil is an antiarrhythmic drug.
- Its effects on circulatory dynamics and myocardial contractility require detailed investigation.
Purpose of the Study:
- To assess the impact of intravenous verapamil on circulatory dynamics.
- To evaluate verapamil's effect on myocardial contractility in patients.
Main Methods:
- Six patients in sinus rhythm were studied (3 controls, 3 with rheumatic valvular disease).
- Verapamil (10 mg) was administered as an intravenous bolus.
- Hemodynamic measurements were recorded at baseline and at 1, 3, 5, and 10 minutes post-administration.
Main Results:
- Left ventricular systolic pressure decreased by 18% at 1 minute (p<0.01), returning to normal by 10 minutes.
- Heart rate increased; cardiac and stroke indices remained unchanged at 5 and 10 minutes.
- Peak LVdp/dt and Vmax decreased, while LV end-diastolic pressure increased, indicating reduced contractility.
Conclusions:
- Intravenous verapamil causes transient reductions in blood pressure and myocardial contractility.
- The observed hemodynamic effects were consistent in both digitalized and non-digitalized patients.
Abstract:
The effect of the antiarrhythmic drug verapamil (Isoptin) on circulatory dynamics and myocardial contractility was studied in six patients in sinus rhythm: three patients were control subjects and three had underlying rheumatic valvular disease. The drug was given as an intravenous bolus (10 mg) and measurements made in the control state and repeated 1, 3, 5 and 10 min after administration of verapamil. Left ventricular (LV) systolic pressure fell by 18% 1 min after intravenous verapamil (p less than 0.01) and returned twoards the range of normal after 10 min. Heart rate increased and cardiac and stroke index were not altered 5 and 10 min after administration of the drug. Peak LVdp/dt and Vmax were reduced while LV end-diastolic pressure increased reflecting a decrease in LV contractility. The hemodynamic effects were similar in digitalised and nondigitalised patients.