Abstract: QT DISPERSION (QTd) in 61 dead patients with acute myocardia infarction (AMI) was measured- 60 live patients with AMI were studied in contrast with 60 normal controls. Our purpose is to proble into infection of increased QTd on prognosis of AMI. The results suggested: (1 ) QTd,QTcd, JTd, JTcd in patiedts with AMI were strikingly higher than that of controls (P CO- O1 ); (2)QTd, QTcd, JTd, JTcd with dead pstients with AMI were higher than of that 1ive patients with AMI (P 0. 05). (3) QTd of AMI patients dead in ventricular fibrillation wps remarkably higher. it lnd1cates that incrased QTd has significance on forecasting prognosis of AMI.