Metabolic exercise data combined with cardiac and kidney indexes: MECKI score. Predictive role in cardiopulmonary exercise testing with low respiratory exchange ratio in heart failure

Cardiopulmonary exercise testing (CPET) is a gold standard for risk assessment in chronic heart failure (HF), but it is effort-dependent, thus influenced bymotivation. Themeasurement of peak respiratory exchange ratio (pRER) is away to ensure that patients are tested at their maximal effort level, as a high pRER is associatedwith energy release from anaerobic metabolism and exercise-induced metabolic acidosis. Regrettably, several HF patients are unable to achieve a high pRER, even though they feel exhausted.