Risk stratification by treadmill testing in acute myocardial infarction following thrombolytic therapy.

Survivors of acute myocardial infarction (AMI) should have risk stratification for assessment of their future risk of cardiovascular events. One of the important means of risk stratification is by treadmill test (TMT). Most of the algorithms for assessment were done in the prethrombolytic era. But in the post-thrombolytic era, risk stratification by TMT should be properly evaluated. Fifty males with confirmed AMI with age ranging from 38-62 years (mean 48 years) were tested with a symptom limited (Modified Bruce Protocol) TMT. The patients were followed up for a minimum of 6 months (range 6-10 months). Out of 50 patients, 38 reported for follow up. Among them 22 (Group A) had cardiac events and 16 (Group B) had no events. Among the patients (Group A), 6 had unstable angina, 7 had reinfarction, 2 had sudden death, 4 had coronary artery bypass grafting (CABG) and 3 had angioplasty. Comparison between the two groups, A and B in TMT parameters like ST segment depression > 2.5 mm (12 vs 9), no. of leads where ST depression occurred (66 vs 48) during exercise, mean work capacity (8.1 vs 7.9 mets), mean systolic blood pressure response were all statistically insignificant. Though TMT was believed to be a good prognostic indicator to assess further cardiac events after AMI, its efficacy in risk stratification after thrombolysis is yet to be determined. This study does not show its worth in post MI risk assessment.