Assessments of functional capacity in cardiac rehabilitation

Functional capacity is an important predictor of mortality in patients with cardiovascular disease. Exercise walk tests, such as the modified shuttle walking test (MSWT) and the six-minute walking test (6-MWT), are the recommended protocols in the United Kingdom for evaluating functional capacity and the effects of therapeutic interventions on patients enrolled in cardiac rehabilitation (CR) programmes. Due to a lack of research into factors associated with walking test performance in cardiac patients, the main aim of this study is to identify whether routinely taken measures (clinical and non-clinical) and biomechanical parameters can predict test performance. A further aim is to establish reference equations or normative values to predict performance in this population. Finally, this research aims to improve the safety of exercise testing and training in community-based CR settings. After determining the long-term reliability of the MSWT, this study investigated the claim that only sex, age and anthropometric parameters (stature and weight), and not biomechanical or simple clinical parameters, can predict functional capacity assessed by the MSWT, in patients with less severe cardiac diseases or by the 6-MWT, in heart failure patients. Overweight heart failure patients showed a 13-fold increase, and older patients (>75 years) had a 5-fold increase, in the risk of poor prognosis via 6-MWT assessment. Furthermore, it is shown here that the effect of stature on the magnitude of change in MSWT results is powerful, and can be used to estimate functional capacity improvement in the cardiac population. Finally, poor functional capacity was shown to have no association with risk of cardiovascular events during exercise, and that exercise testing and training can be carried out safely in supervised community-based CR settings. These findings have implications in clinical practice and CR programme improvement, as they can help clinicians to make better-informed decisions about cardiac patients entering CR.