Over the last several decades there has been an impressive expansion in the study and management of cardiac arrhythmias. New developments in diagnostic and interventional clinical electrophysiology as well as research at the cellular tissue and whole heart levels have improved our understanding of the mechanisms of arrhythmias and have allowed the development of new and effective treatment modalities. During the 1960s (Early Decade-Enabling) the first lifesaving measures such as cardiac resuscitation, external defibrillation, and temporary pacing were introduced in the new coronary care units. Cardiac catheterization and reproducible techniques for recording of intracardiac potentials were developed. The decade of 1970 to 1980 (Middle Decade-Diagnosis) was characterized by the development of programmed stimulation for initiation and termination of arrhythmias. This represented a real revolution in clinical cardiology that led to the understanding of the nature of several tachyarrhythmias and related them to experimental mechanisms of arrhythmogenesis. In the same decade, two other diagnostic tools emerged for assessing cardiac arrhythmias and monitoring the efficacy of antiarrhythmic drug therapy: ambulatory ECG monitoring and exercise testing. In addition, the impact of antiarrhythmic drugs on ionic currents was studied and drug classifications based on these properties appeared. The decade 1980-1990 (Recent Decade-Therapy), witnessed the development of interventional electrophysiology techniques such as transcatheter ablation, and the use of cardiac surgery for the ablation of arrhythmogenic substrates. Another major advance was the design of implantable devices capable of recognizing tachyarrhythmias and treating them by programmed stimulation or defibrillation shocks. In parallel, the efficacy and safety of antiarrhythmic drugs has been reassessed and new compounds are being developed.(ABSTRACT TRUNCATED AT 250 WORDS)