An Index for Evaluating Exercise Capacity Improvement After Cardiac Rehabilitation in Patients After Myocardial Infarction

Abstract

We investigated relationships among predictors of improvement in exercise capacity after cardiac rehabilitation programs in patients after acute myocardial infarction. Methods: We carried out a secondary analysis of data from 41 patients with a left ventricular ejection fraction ≥ 40% who underwent cardiac rehabilitation after the first myocardial infarction. Participants were assessed using a cardiopulmonary exercise test and stress echocardiography. A cluster analysis was performed, and the principal components were analyzed. Results: Two distinct clusters with significantly different ( P = .005) proportions of response to treatment (peak VO 2 ≥ 1 mL/kg/min) were identified among patients. The first principal component explained 28.6% of the variance. We proposed an index composed of the top 5 variables from the first component to represent the improvement in exercise capacity. The index was the average of scaled O 2 uptake and CO 2 output at peak exercise, minute ventilation at peak, load achieved at peak exercise, and exercise time. The optimal cutoff for the improvement index was 0.12, which outperformed the peak VO 2 ≥ 1 mL/kg/min criterion in recognizing the clusters, with a C-statistic of 91.7% and 72.3%, respectively. Conclusion: The assessment of change in exercise capacity after cardiac rehabilitation could be improved using the composite index.

Development of a prediction model for exercise tolerance decline in the exercise assessment of patients with acute myocardial infarction undergoing percutaneous coronary intervention revascularization in the acute phase

“…It’s widely recognized that exercise incapacity serves as a significant forecaster of adverse outcomes and impairment, not only in patients grappling with cardiovascular disease and chronic heart failure, but also within the general populace ( 3 - 5 ). The cardiopulmonary exercise test (CPET) measures peak oxygen consumption (VO 2 peak), which is widely used as the gold standard for measuring exercise capacity ( 6 , 7 ). Additionally, the CPET has become the most important and valuable noninvasive diagnostic test for clinical evaluation of cardiac rehabilitation in patients with AMI and is also widely used to evaluate the efficacy of PCI.…”