What is the optimal evaluation time of the QT dispersion after acute myocardial infarction for the risk stratification?

The sequential changes of the corrected QT dispersion (QTcD) were studied i n 136 patients 1 day to 30 days after a transmural acute myocardial infarct ion (AMI) to investigate the optimal measurement time of QT dispersion for risk stratification. The study group included 136 patients (89 men; mean ag e, 57 +/- 10 years) with transmural AMI who were treated with thrombolytics (Tr+ group, n = 73) or not (Tr- group, n = 63) and 65 healthy controls (43 men; mean age, 56 +/- 7 years). Fourteen patients in whom ventricular tach ycardia (VT), ventricular fibrillation (VF), or sudden cardiac death develo ped during the 30-day period were also evaluated as major cardiac arrhythmi a (MCA) group. ECGs were obtained for each patient on days 1, 3, 5, 10, 15, and 30 after AMI. QTc dispersion in patients with AMI (for every period of QTcD after Mi) was significantly more prolonged than in normal controls (4 9.3 +/- 16.3 ms) (p < 0.001). QTcD was significantly greater in patients wi thout thrombolytics than in patients with thrombolytics for every period (d ays 1, 3, 5, 10, 15, and 30) of QTcD after MI (p < 0.001). The mean of QTcD was significantly greater in patients with MCA than in patients without MC A group for every period (days 1, 3, 5, 10, 15, and 30) of QTcD after MI (p < 0.05). Maximal QTcD was seen on day 10 (p < 0.05 Ist vs day 10 for each group) after myocardial infarction, and then reached a plateau for an each group. The ideal time to measure the QTD for risk stratification is at leas t 10 days after AMI.