Intracoronary ST-T alternans during coronary balloon angioplasty.
To evaluate the presence and clinical significance of electrical alternans during PTCA, intracoronary electrocardiography (ic-ECG) was performed in 65 consecutive lesions. ST-T alternans, defined as a beat-to-beat difference in the ST elevation > or = 1 mm, was present in five lesions (7.7%), all in the proximal left anterior descending (LAD) coronary artery. The phenomenon was seen only after 130 sec (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 alternans. Three of these five lesions required a second balloon inflation with duration of > or = 300 sec; there was no ST-T alternans 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 requisite 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 phenomenon.
Kwan
T
T
Department of Medicine, State University of New York, Health Science Center, Brooklyn 11203, USA.
Feit
A
A
Chadow
H
H
Chio
F
F
Huber
M S
MS
Chebaclo
M
M
Breitbart
S
S
Stein
R A
RA
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015906:Angioplasty, Balloon, Coronary / Q000379:methods; D003331:Coronary Vessels / Q000503:physiopathology; D004562:Electrocardiography / Q000379:methods; D004594:Electrophysiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative; D017202:Myocardial Ischemia / Q000175:diagnosis*; D012680:Sensitivity and Specificity