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
Serious
Sustained
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 of arrhythmogenic foci in patients with supraventricular tachycardia, atrial fibrillation, and ventricular tachycardia, particularly when refractory to pharmacologic therapy.
