Abstract: From 1974-1984 among 1197 cases of AMI admitted into our hospital,262 cases were complicated with supraventricular arrhythmias with anincidence of 21.8%.The supraventricular arrhythmias in this group included APB,JPB,PSVT,Atrial Flutter and Atrial Fibrillation.The types,causative factors and prognosis were discussed and theresults revealed that supraventricular arrhythmias were significantly morefrequent in patients with congestive heart failure and not definitelyrelated to the location of AMI,the blood supply to the sino-atrial node,the occurrence of pericarditis and atrial injury.The mortality of AMI complicated with supraventricular arrhythmiaswas not different from that of the total group of AMI,but we consideredthat when supraventricular tachyarrhythmias especially atrial fibrillationand PSVT were secondary tn congestive heart failure,they could causethe cardiac performance to deteriorate further and the mortality toincrease significantly.If effective treatment with digoxin or cardioversion was promptlygiven to improve the cardiac performance,the mortality might bedecreased.