Long-term evaluation of early repolarization syndrome (normal variant RS-T segment elevation).

The electrocardiograms of 65 patients with the "early repolarization syndrome" (normal variant of RS-T elevation) were analyzed to delineate the features and evaluate the natural history of this electrocardiographic entity. Maximal follow-up was 26 years. The syndrome was characterized by (1) an upward concave elevation of the RS-T segment with distinct or "embryonic" J waves, slurred downstroke of R waves or distinct J points or both; (2) RS-T segment elevation commonly encountered in the precordial leads and more distinct in these leads; (3) rapid QRS transition in the precordial leads with counterclockwise rotation; and (4) persistence of these characteristics for many years although some intraindividual changes were common. Less commonly found were (5) tall R and T waves in the precordial leads; (6) "labile" or "juvenile" T wave patterns; (7) "pseudo-R" waves; and (8) "isolated T negativity syndrome." These changes commonly simulate pericarditis, myocardial ischemia, left ventricular hypertrophy and right bundle branch block.