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Prognosis in patients with low left ventricular ejection fraction after myocardial infarction. Importance of exercise
L Pilote1, J Silberberg, R Lisbona
1Division of Cardiology, Royal Victoria Hospital, Montreal, Quebec, Canada.
Insights
Exercise capacity after myocardial infarction provides crucial prognostic information for patients with low left ventricular ejection fraction (LVEF). This assessment aids in stratifying risk for death or reinfarction, independent of LVEF alone.
Area of Science:
- Cardiology
- Clinical Medicine
- Exercise Physiology
Background:
- Left ventricular ejection fraction (LVEF) is vital for managing patients post-myocardial infarction (MI).
- Accurate risk stratification is essential for optimizing patient outcomes after acute MI.
Purpose of the Study:
- To determine if exercise capacity 1 month post-MI offers additional prognostic value in patients with reduced LVEF.
- To assess the utility of exercise testing for risk stratification in this patient cohort.
Main Methods:
- A cohort of 115 patients with MI and LVEF < 35% was studied.
- Exercise capacity was assessed via treadmill testing 1 month post-MI.
- Patients were followed for 2 months to 7 years, with outcomes including death or reinfarction.
Main Results:
- Exercise capacity was a significant predictor of death or reinfarction (Cox proportional hazards model).
- Patients in the lowest exercise capacity quintile (< 4 METS) had a 3.5-fold higher risk of adverse events compared to the highest quintile (> 7 METS).
- The prognostic value of exercise capacity was independent of LVEF in multivariate analysis.
Conclusions:
- Exercise testing 1 month after myocardial infarction provides significant prognostic information in patients with low LVEF.
- Exercise capacity assessment can enhance risk stratification beyond LVEF alone.
- Treadmill testing is a valuable tool for identifying high-risk patients post-MI.
Abstract:
The measurement of left ventricular ejection fraction (LVEF) plays a key role in many strategies for managing patients after acute myocardial infarction. We tested the hypothesis that exercise capacity 1 month after myocardial infarction provides additional information in patients with a low LVEF and therefore assists in risk stratification. One hundred fifteen patients, with documented myocardial infarction and LVEF less than 35% by gated radionuclide scan 1 month after acute myocardial infarction, were followed up for 2 months to 7 years. Exercise capacity was estimated from a treadmill test 1 month after infarction. Using the Cox proportional hazards model, exercise capacity was a significant predictor of death or reinfarction. The relative risk of death, based on a comparison between the lowermost quintile (less than 4 METS) and uppermost quintile (greater than 7 METS), was 3.5 (95% confidence interval, 1.1-9.7); the relative risk in the fourth, third, and second quintile was 2.7, 2.1, and 1.6, respectively. In a multivariate analysis, the observed effect of a good exercise capacity was independent of LVEF. These data indicate that in patients with a low LVEF after myocardial infarction, useful prognostic information can be obtained from exercise testing.