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Determinants of exercise tolerance after acute myocardial infarction in older persons
N Marchionni1, F Fattirolli, S Fumagalli
1Department of Gerontology and Geriatric Medicine, University of Florence, Italy.
Objectives:
Exercise tolerance is reduced with advancing age. Identification of potentially reversible determinants of the age-related decrement in exercise tolerance, which remain largely unexplored in older subjects and in patients recovering from a recent myocardial infarction (MI), may have useful therapeutic implications. The objective of this study was to identify the independent determinants of exercise tolerance in older patients with a recent MI.
Design, Setting, And Participants:
Data is from baseline assessment of 265 post-MI patients (age range 45-85 years) enrolled in the Cardiac Rehabilitation in Advanced Age randomized, controlled trial. Patients with major comorbidities or severe MI complications were excluded from the trial. Exercise tolerance was determined from symptom-limited exercise testing and expressed as total work capacity (TWC, kg.m) or peak oxygen consumption (VO2peak, mL/kg/min). The associations between both TWC and VO2peak and baseline demographic, social, clinical, and neuropsychological variables and an index of health-related quality of life were determined with univariate and multivariate analysis.
Results:
With univariate analysis, TWC decreased by 1285 kg.m per decade of increasing age between 45 and 85 years of age. With multivariate analysis, TWC decreased by 922 kg.m per decade. Increasing age (P < .001), female gender (P < .001), a small body surface area (P < .001), a low level of usual physical exercise before MI (P < .002), and the presence of post-MI depressive symptoms (P < .024) were independently associated with a lower TWC. The same factors, in addition to a small arm muscle area (P < .002), were also independently associated with a lower VO2peak.
Conclusions:
Age per se accounts for approximately 70% of the age-related decay in TWC or VO2peak. However, the inclusion of modifiable factors such as physical exercise and depression in the prediction model reinforces the importance of a multidimensional approach to the evaluation and treatment of older patients with a recent MI.