INTRACORONARY ST-T ALTERNANS DURING CORONARY BALLOON ANGIOPLASTY

To evaluate the presence and clinical significance of electrical alter nans during PTCA, intracoronary electrocardiography (ic-ECG) was perfo rmed in 65 consecutive lesions, ST-T alternans, defined as a beat-to-b eat difference in the ST elevation greater than or equal to 1 mm, was present in five lesions (7.7%), all in the proximal left anterior desc ending (LAD) coronary artery, The phenomenon was seen only after 130 s ec (mean 174 +/- 57) of balloon inflation. Only two of the five showed ST-T alternans simultaneously on both surface and ic-ECG, One of five patients had premature ventricular contractions following ST-T altern ans, Three of these five lesions required a second balloon inflation w ith duration of greater than or equal to 300 sec; there was no ST-T al ternans on the second inflation in any of these lesions, We conclude: (1) the detection of ST-T alternans during PTCA is enhanced by use of ic-ECG, (2) electrical alternans during PTCA was seen only in proximal LAD lesions, implicating a large amount of ischemic myocardium as a r equisite for the phenomenon, (3) electrical alternans is not immediate , requiring a certain duration of balloon occlusion and hence ischemia to occur, and (4) the absence of ST-T alternans during second balloon inflations suggests ischemic preconditioning may abolish this phenome non. (C) 1995 Wiley-Liss, Inc.