Ventilatory Abnormalities During Exercise in Heart Failure: A Mini Review

Heart Failure (HF) is a significant health care concern with in both the United States and Europe. While there are a number of mechanisms that lead to HF, a decline in the response to exercise is common amongst the various etiologies. Cardiopulmonary exercise testing (CPET) is a well established diagnostic and prognostic tool in the HF population. This exercise testing technique allows for the measurement of oxygen consumption (VO2), carbon dioxide production (VCO2) and minute ventilation (VE) across time. Cardiovascular and skeletal muscle dysfunction is considered central to the often abnormal exercise response observed in the HF population. As such, VO2 at peak exercise is the most recognized CPET variable in patients with HF. In recent years however, the importance of assessing VE during exercise, either alone or in combination with expired gases, has been highlighted in a number of investigations. The VE-VCO2 relationship, exercise periodic breathing (EPB) and the oxygen uptake efficiency slope (OUES) are, to this point, the most studied CPET measurements incorporating VE in the HF population. Of these, the VE-VCO2 relationship has received the greatest amount of attention. This review will address the clinical significance of these CPET measurements in the HF population.