DYNAMICS OF QT DISPERSION DURING MYOCARDIAL-INFARCTION AND ISCHEMIA

We studied the dynamics of QT dispersion over the first few days of my ocardial infarction and during coronary angioplasty. Ten patients with anterior myocardial infarction and an equal number with inferior infa rction had electrocardiograms (ECGs) recorded on admission to hospital (day 1), on the subsequent 2 days (day 2, 3), and prior to discharge (day 6). Ten patients undergoing therapeutic coronary angioplasty were studied; ECGs were recorded prior to, during; and after balloon infla tion. Simultaneous 12-lead ECGs were scanned into a personal computer; specially designed software skeletonised and joined each image. The i mages were then available for user-interactive measurement of QT dispe rsion. Mean (S.D.) QTc dispersion on day 1 of acute myocardial infarct ion was 107 (44.8) ms, rose further over the next 48 h, reaching a max imum on day 3 (QTc dispersion, 162.3 (64.8) ms, P<0.01), and was falli ng by hospital discharge (QTc dispersion, 117.4 (67.4) ms). There was no difference in QT dispersion measurement during coronary angioplasty . It is unlikely that acute ischaemia plays an important role in the d ynamic changes seen in QT dispersion over the first few days of myocar dial infarction. These rapid changes in QT dispersion have important i mplications in the design of any study of QT dispersion after myocardi al infarction, and in comparison of studies.