Aborted Myocardial Infarction

"Aborted myocardial infarction" is a term first coined by Weaver when reporting the MITI trial of prehospital fibrinolysis.

Aborted MI is characterised by:

1. Resolution of ST elevation by > 50% from the initial levels in presentation ECG after 90 minutes post-fibrinolysis, and

2. Absence of cardiac enzyme elevation, or an increase less than twice the upper limits of normal

Early fibrinolysis results in lesser degrees of myocardial injury and necrosis thereby preventing significant enzyme release. An increased incidence of aborted infarction has been reported with prehospital fibrinolysis, patients with prior angina and well developed coronary collaterals, and with lesser degrees of ST elevation in the initial ECG.

The therapeutic significance of an aborted infarction lies in the fact that the extent of myocardial necrosis is less along with the presence of potentially viable myocardium thereby necessitating early coronary angiography and revascularisation procedures.