Clinical cardiac electrophysiology: history, rationale, and future.

The discipline of clinical cardiac electrophysiology has evolved over the past 40 years. Intense interest has resulted in the clinical application of intracardiac electrophysiologic techniques over the past 20 years. Clinical cardiac electrophysiologic studies have developed since the demonstration that programmed electrical stimulation could be performed in the human heart to evaluate tachyarrhythmias and that cardiac electrical activity that could not be detected on the body surface could be measured with intracardiac electrodes. Clinical electrophysiologic techniques have evolved for the assessment of sinus nodal, AV nodal, and His-Purkinje system function. The evaluation of tachyarrhythmias has progressed rapidly, and pharmacologic, device, and surgical therapy can now be guided by electrophysiologic studies. Invasive electrophysiologic studies have confirmed the utility of noninvasive electrocardiographic analysis and in several circumstances have proved that invasive studies are not necessary. Alternatives to invasive electrophysiologic evaluation continue to be debated. It is clear that when performed by well-trained individuals in appropriately equipped laboratories, electrophysiologic studies are safe and can be shown to be beneficial. Clinical cardiac electrophysiology continues to evolve, and problems of uniformity of methods, definitions of terms, and protocols remain to be resolved. The future of clinical cardiac electrophysiology appears to be one of continued evolution of techniques, refinement of indications, and continued clinical applications.