Rodolphe Ruffy, MD, Assistant Professor of Medicine, Director, Cardiac Electrophysiologic Laboratories and Heart Station, Washington University School of Medicine, The Jewish Hospital of St Louis: In the past few years, the indications for invasive cardiac electrophysiologic studies have shifted from cases of atrioventricular conduction disorders or sinoatrial dysfunction to patients suffering from paroxysmal supraventricular tachycardia, wide QRScomplex tachycardia of unclear nature, or recurrent ventricular tachycardia and/or fibrillation. In such conditions, these studies are helpful in making a correct diagnosis as well as in selecting the appropriate therapy. Diagnostic indications for cardiac electrophysiologic studies are sporadic disorder of cardiac rhythm, equivocal mechanism of dysrhythmia, and equivocal association between symptoms and paroxysmal dysrhythmia; therapeutic indications are short-term drug testing, artificial termination and/or suppression of dysrhythmia, and preoperative intracardiac mapping. In addition, artificial electrical stimulation of the heart may be a reliable detector of subjects at high risk of sudden death.
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