Differential characteristics of the electrocardiogram in early repolarization and acute pericarditis.

Electrocardiographic mimicry necessitates differentiation between acute pericarditis and early repolarization. Among 96 persons, limb-lead RST deviations occurred in all 48 with pericarditis, but only 27 with early repolarization. RS-T vectors (A RS-T) in pericarditis tended to be horizontal (25 patients) and left of the T vector, A T (28 patients); in early repolarization, A RS-T was vertical in 15 subjects and right of A T (20 subjects); P less than or equal to 0.01. RS-T depression in Lead V1 was more common in pericarditis (14 vs. two); isoelectric RS-T in Lead V6 was more common in early repolarization (10 vs. one); P less than or equal to 0.01. PR segment deviations occurred in both limb and precordial leads in pericarditis; in early repolarization they were confined to either lead group. Thus, R-ST deviations in both limb and precordial leads with horizontal A RS-T to left of A T and RS-T depression in Lead V1 favor pericarditis; vertical A RS-T and isoelectric RS-T in Lead V6 favor early repolarization.