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Electrophysiological effect of disopyramide on rabbit sinus node cells.
Journal of Electrocardiology
|October 1, 1985
Summary
Disopyramide slows heart rate by reducing electrical activity in sinus node cells. This antiarrhythmic drug depresses key ion currents, impacting cardiac electrical function.
Area of Science:
- Cardiac Electrophysiology
- Pharmacology
Background:
- Sinus node cells control heart rhythm.
- Antiarrhythmic drugs modulate cardiac electrical activity.
Purpose of the Study:
- Investigate disopyramide's effects on rabbit sinus node cell electrophysiology.
- Determine the ion current mechanisms underlying disopyramide's chronotropic effects.
Main Methods:
- Conventional microelectrode technique.
- Voltage clamp analysis.
- Rabbit sinus node cell models.
Main Results:
- Disopyramide decreased heart rate and action potential parameters.
- Reduced potassium outward current (IK) without altering kinetics.
- Decreased slow inward current (Isi) and hyperpolarization-activated current (Ih).
Conclusions:
- Disopyramide depresses sinus node electrical activity.
- Inhibition of IK, Isi, and Ih mediates disopyramide's negative chronotropic effect.