Arq. Bras. Cardiol. 2022; 119(3): 424-425

Measurement of PETCO2 at Anaerobic Threshold: A Best Prognostic Marker in Patients with Cardiac Resynchronization Therapy?

Anderson Donelli da Silveira , Maurício Pimentel

DOI: 10.36660/abc.20220477

This Short Editorial is referred by the Research article "Predictive Ability of Cardiopulmonary Exercise Test Parameters in Heart Failure Patients with Cardiac Resynchronization Therapy".

The cardiopulmonary exercise test (CPET) is a consolidated tool in the functional and prognostic assessment of patients with heart failure with reduced ejection fraction (HFrRF), being a cornerstone in the evaluation for the indication of advanced therapies in HFrEF. ^, Cardiac resynchronization therapy (CRT), in addition to reducing mortality, can improve cardiorespiratory fitness, leading to an increase in peak oxygen consumption (VO₂peak) and a reduction in the slope of the respiratory equivalent CO2 ratio (VE /VCO2 slope). ^– In recent years, with the evolution of treatments, general mortality and the risk of the sudden death of patients with HFpEF have been reduced. ^, In this context, reviewing the prognosis and the values associated with a higher risk among the CPET variables in patients undergoing CRT becomes important.

The measurement of end-tidal carbon dioxide pressure (PETCO2) during CPET, both at rest, and at the first ventilatory threshold or anaerobic threshold (P_ETCO2_LA), has a well-established prognostic value in heart failure. ^, The increase of dead space ventilation, caused by the impairment of the ventilation/perfusion (V/Q) ratio, for example, in patients with left ventricular dysfunction, leads to a reduction in alveolar CO2 and, consequently, in P_ETCO₂. It is expected that there will be an increase in its measurement up to the anaerobic threshold, which is correlated with an increase in cardiac output.

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