[Usefulness and pitfalls in clinical electrophysiological studies]

Clinical electrophysiological studies(EPS) have become useful tools for specific cardiac arrhythmias. However, these studies are expensive and occasionally cause major as well as minor complications such as serious arrhythmias, cardiac tamponade or thromboembolism. It is important to consider guidelines for clinical application of invasive studies. The indications for clinical electrophysiological studies have been categorized into three classes. Class 1: All experts agree that EPS is useful and important for patients treatment and patients with these condition benefit from EPS. Class 2: There is less certainty about usefulness of the information from EPS. Class 3: EPS does not provide useful information. EPS should be performed by trained cardiologist in adequately equipped laboratory. Such studies are performed either by intracardiac pacing and recording or esophageal pacing and recording, and evaluate electrophysiological properties such as automaticity, conduction and refractoriness; initiate and terminate tachycardias; mechanism of tachycardia by activation mapping and pace mapping; evaluate for antiarrhythmic drug, catheter ablation, and intracardiac defibrillator. EPS is useful tool for analysis of bradyarrhythmias and tachyarrhythmias and bring us useful information for the choice of treatment but has its limitation and pitfalls. In general, EPS is not so important to determine the indication of pacemaker for bradyarrhythmias such as sick sinus syndrome or atrioventricular(AV) block. But, it is very useful to analysis tachyarrhythmias and indicate antiarrhythmic drugs or catheter ablation for patients with Wolf-Parkinson-White(WPW) syndrome, AV nodal reentrant tachycardia, atrial tachycardia, atrial flutter, or ventricular tachycardia to cure the tachyarrhythmias.