In electrophysiologic studies (EPS), recording and stimulating electrodes are inserted into all 4 cardiac chambers via right- or left-sided cardiac catheterization. Atria are paced from the right or left atrium, ventricles are paced from the right ventricular apex or right ventricular outflow tract, and cardiac conduction is recorded. Various mapping techniques are available. Programmed stimulation techniques may be used to trigger and terminate a reentrant arrhythmia.
Electrophysiologic studies are indicated primarily for evaluation and treatment of arrhythmias that are
- Difficult to capture
These studies may be used to make a primary diagnosis, to evaluate the efficacy of antiarrhythmic drugs, or to map arrhythmia foci before catheter ablation.