Related Experiment Videos
Effect of procainamide on myocardial contractile function and digoxin inotropy
Journal of the American College of Cardiology
|December 1, 1984
Summary
Procainamide enhances heart muscle contractility in therapeutic doses, but this effect is masked during high contractile states. Its positive inotropic action is linked to calcium channels and beta-adrenergic stimulation, not altering digoxin
Area of Science:
- Cardiovascular Pharmacology
- Cardiac Electrophysiology
Background:
- Procainamide is an antiarrhythmic drug.
- Digoxin is a cardiac glycoside used to treat heart failure.
Purpose of the Study:
- To investigate the effects of procainamide and digoxin on right ventricular papillary muscle contractility.
- To determine the interaction between procainamide and digoxin on cardiac muscle function.
Main Methods:
- Isolated right ventricular papillary muscles from adult cats were used.
- Muscles were exposed to varying concentrations of procainamide and digoxin.
- Force development and rate of force development were measured.
Main Results:
- Procainamide demonstrated dose-dependent positive inotropic effects.
- These effects were attenuated at high contractile states.
- Propranolol reduced and verapamil abolished procainamide's inotropic effect.
- Procainamide did not alter digoxin's inotropic action.
Conclusions:
- Procainamide exhibits significant positive inotropic effects within therapeutic concentrations.
- The mechanism involves calcium channels and potentially beta-adrenergic stimulation.
- Procainamide's inotropic effects can be masked by increased cardiac workload.
- Procainamide does not interfere with digoxin's positive inotropic effects.