Persistent changes in the body surface electrocardiogram following successful coronary angioplasty

One hundred twenty-lead body surface potential maps (BSPMs) were recorded immediately before and 24 hours after coronary angioplasty (PTCA) in 24 patients with symptomatic coronary aftery disease (single-vessel in 21 and two-vessel in 3). All PTCAs were uncomplicated and successful. The modified Gensini score decreased in every patient and the mean score fell from 43±36 to 21±28 (p<0.001). Resting spatial patterns of QRS, ST-segment, and T wave integral distributions over the torso surface were, unchanged from before to after PTCA. Quantitative temporal subtraction maps, however, revealed a large precordial area of decreased T wave integral values after PTCA. The sum (Σ) positive T wave integrals fell from 20,501±10,544 μV.s before PTCA to 17,647±10,310 μV.s after PTCA (p<0.02). In contrast, the Σ positive QRS (10,115±4,848 μ V.s before PTCA vs. 9,656±4,556 μV.s after PTCA) and the Σ negative ST integrals (-2,489±1,467 μV.s before PTCA vs. -2,359±1,505 μV.s after PTCA) were unchanged (NS). Thus, successful PTCA does not produce any persistent change in depolarization or early repolarization electrocardiographic variables but is associated with a decrease in late repolarization potentials that persists for at least 24 hours after the procedure. The pathophysiology of this persistent change is speculative, but myocardial ischemia during the PTCA procedure is a likely possibility. The clinical significance, including predictive value for subsequent stenosis, and the natural history of T wave effect remain incompletely defined. These data suggest that measures to decrease myocardial ischemia during PTCA are warranted.