• Fátima Palha de Oliveira and Roberto Coury Pedrosa.
• Hospital Universitário Clementino Fraga Filho, Universidade Federal do Rio de Janeiro, Rua das Laranjeiras 136/203, CEP 22240-000, Rio de Janeiro(RJ), Brazil. palha@ufrj.br
• Sao Paulo Med J. 2006 Sep 7; 124 (5): 280284280-4.

Context And ObjectiveThe change in slope of the .VE/.VCO2 curve with time during exercise (.VE/.VCO2 slope) has been recommended as a parameter for analyzing the ventilatory response during exercise among patients with heart failure of different etiologies. The aim of this work was to evaluate the ventilatory response among patients with chronic Chagas cardiopathy.MethodsForty-eight patients, divided into four groups according to the Los Andes clinical/hemodynamic classification, were studied. They were also classified according to peak oxygen uptake (peak .VO2) for a second analysis. The results from the patients were compared with results from a control group consisting of 21 healthy male volunteers (no Chagas disease). Exercise was performed on a cycle ergometer with loads increasing at the rate of 12.5 watts/min, and exercise duration was symptom-limited. Gas concentration and flow rate data were fed into a computer, which produced a real-time report on ventilatory and gas exchange parameters (breath-by-breath). The ventilatory parameters of .VE/.VCO2 slope and .VE/.VCO2 ratio computed at different times of the test were adopted.ResultsAlthough there were no significant differences in .VE/.VCO2 ratio and .VE/.VCO2 slope when patients were grouped using the Los Andes clinical/hemodynamic classification, these parameters varied significantly when peak .VO2 was used to define patient groups.ConclusionOur results indicate that progressive deterioration in ventilatory response among chronic Chagas cardiopathy patients during exercise is more evident when the functional capacity (peak .VO2) is reduced, than when changes are related to the Los Andes classification.

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