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[Prognostic value of the exercise test performed less than 40 days after the first infarction]
Insights
Early stress testing after myocardial infarction helps identify high-risk patients. A negative test predicts an asymptomatic outcome, while a positive ischemic test indicates higher risks of post-infarction angina and bypass surgery.
Area of Science:
- Cardiology
- Exercise Physiology
Context:
- Post-primary myocardial infarction (MI) management.
- Evaluating early risk stratification in cardiac patients.
Purpose:
- To assess the predictive value of early stress testing (ST) following primary myocardial infarction.
- To correlate ST results with clinical outcomes over a 2-year follow-up period.
Summary:
- 159 men underwent ST 10-40 days post-MI. 53% had negative tests, 47% positive (23% ischemic, 24% non-ischemic). Over 2 years, 44% experienced post-infarction angina, 7% recurrent MI, and 4% died. Negative ST predicted asymptomatic outcomes (p<0.001).
- Positive ischemic ST correlated significantly with post-infarction angina and need for coronary bypass surgery (p<0.001).
- ST accuracy improved when performed 10-11 weeks post-MI compared to earlier testing, though early ST identified high-risk subgroups.
Impact:
- Early stress testing is valuable for identifying high-risk patients after myocardial infarction.
- Stress test results significantly predict the likelihood of developing post-infarction angina and requiring coronary bypass surgery.
- Optimal timing for stress testing post-MI is between 10-11 weeks for improved predictive accuracy, though early testing remains crucial for risk stratification.
Abstract:
Stress testing was performed in 159 men (mean age 49.83 years) between the 10th and 40th day after primary myocardial infarction. The average work achieved was 79 watts with a heart rate of 121/min, systolic blood pressure of 169 mmHg, and a double product of 20 544. The result was negative in 53 p. 100 of cases, and positive in 47 p. 100: the positive response was ischaemic in 23 p. 100 and non ischaemic in 24 p. 100 of cases. In the 2 years which followed, post-infarction angina was observed in 44 p. 100 of cases (14 p. 100 unstable angina), recurrent infarction in 7 p. 100 and death in 4 p. 100; coronary angiography was performed in 19 p. 100 of cases and coronary bypass surgery in 6 p. 100; 53 p. 100 of patients remained asymptomatic. The difference in predictive value between negative stress testing for an asymptomatic outcome and a positive ischaemic test for post-infarction angina and bypass surgery was important (p less than 0.001). The correlation was not as significant for death and recurrent infarction. The non-ischaemic positive result was of less value. There was no relationship to age but the prediction was more accurate in postero-inferior (p less than 0.001) than anterior infarction (p less than 0.05). The timing of the test affected the performance and patient comfort but had less influence on the results. Nevertheless, the predictive values were less good at 2 weeks than later on and significantly improved when testing was performed between the 10th and 11th week. However, early stress testing was valuable for identifying high risk subgroups.