Ventricular arrhythmias and electrophysiological consequences of myocardial ischemia and infarction.

The derangements of cardiac rhythm that result from occlusion of coronary arteries caught the attention of the earliest experimenters in the field. By the time of the studies of Porter in 1894, it was known that "fibrillar contractions" often were the end result of coronary occlusion and that irregularities of cardiac rhythm commonly preceded terminal ventricular fibrillation. Porter remarked that the pioneer investigator, Erichsen, in 1842, saw a "slight tremulous motion" after cessation of the regular heart beat following coronary occlusion. To Porter, disturbance of the cardiac rhythm was the salient feature of coronary occlusion. Thomas Lewis, in 1909, demonstrated the relationship of paroxysmal ventricular tachycardia to coronary occlusion in experimental animals; Robinson and Hermann, in 1921, established this relationship in man. Clinicians observed a multitude of arrhythmias resulting from ischemia and infarction but the fascination of experimenters with ischemic rhythm disorders waned. During the first half of the 20th century, the attention of researchers was focused more on the effects of ischemia and infarction on the configuration of the ventricular complexes, the QRS and T waves, than on rhythm.