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Haemodynamic effect of intravenous verapamil in controlled atrial fibrillation
Insights
Intravenous verapamil slowed heart rate and increased stroke volume in patients with atrial fibrillation. However, it did not regularize the R-R interval or significantly change cardiac output during rest or exercise.
Area of Science:
- Cardiology
- Pharmacology
Background:
- Atrial fibrillation is a common arrhythmia affecting ventricular rate control.
- Verapamil is a calcium channel blocker used in managing cardiac conditions.
Purpose of the Study:
- To assess the haemodynamic effects of intravenous verapamil in digitalised patients with atrial fibrillation.
- To examine the effect of verapamil on ventricular rate regularization during rest and exercise.
Main Methods:
- Eight patients with atrial fibrillation, who were digitalised, were studied.
- Haemodynamic parameters were measured at rest and during and after exercise.
- Intravenous verapamil was administered.
Main Results:
- A significant slowing of heart rate occurred at rest, during, and after exercise.
- Stroke volume significantly increased, consistent with heart rate slowing.
- Cardiac output remained unchanged.
- Regularisation of the R-R interval was not observed despite heart rate slowing.
Conclusions:
- Intravenous verapamil effectively slows heart rate and increases stroke volume in digitalised patients with atrial fibrillation.
- Verapamil does not consistently regularize the ventricular rhythm in atrial fibrillation.
- The haemodynamic effects of verapamil are significant for stroke volume and heart rate but not cardiac output in this patient group.
Abstract:
The haemodynamic effect of intravenous verapamil was assessed in eight digitalised patients with atrial fibrillation, at rest and on exercise. The reported regularisation of the ventricular rate in atrial fibrillation with verapamil, was also examined. The only significant haemodynamic effect attributable to the drug was an increased stroke volume which was in accordance with significant heart rate slowing which occurred at rest and both during and after exercise. There was no significant change in cardiac output. Although the heart rate slowed in all studies, regularisation of the R-R interval did not occur.