How to perform and report a cardiopulmonary exercise test in patients with chronic heart failure.

In the present practice review, we will explain how to perform and interpret a cardiopulmonary exercise test (CPET) in heart failure patients. Specifically, we will explain why cycle ergometer should be preferred to treadmill, the type of protocol needed, and the ideal exercise duration. Thereafter, we will discuss how to interpret CPET findings and determine the parameters that should be included. We will focus specifically on: peak VO2 (absolute value and a percentage of its predicted value), exercise duration, respiratory exchange ratio, peak work rate, heart rate, O2 pulse, end-tidal carbon dioxide pressure (PetCO2), PetO2, and -if blood gas samples are obtained-dead space to tidal volume ratio. Moreover, we will discuss the physiological and clinical value of anaerobic threshold, respiratory compensation point, ventilation vs. VCO2 and VO2 vs. work relationships. Finally, attention will be dedicated to exercise-induced periodic breathing. We will also discuss when and why CPET should be integrated with other measurements in the so-called complex CPET. Specifically: a) when and how to use a complex non-invasive CPET, which integrates CPET measurements with non-invasive cardiac output determination, working muscle near-infrared spectroscopy, transthoracic echocardiography, thoracic ultrasound, and lung diffusion analysis; b) when and how to use a complex minimally invasive CPET, in which CPET is combined with esophageal balloon recordings or with serial arterial blood sampling for blood gas analysis; c) when and how to use a complex invasive CPET, which usually implies the presence of a Swan Ganz catheter in the pulmonary artery and an arterial line.