[Prognostic factors of cardiac insufficiency: value of functional exercise capacity. Maximal oxygen consumption, anaerobic threshold].

This study concerned 43 patients with chronic cardiac failure. Twenty two patients had primary dilated cardiomyopathy and twenty one had ischaemic cardiomyopathy. Fifteen patients were in the NYHA functional Class II, 20 in Class III and 8 in Class IV. The parameters studied during a bicycle ergometric exercise stress test were the developed power (W), the duration (in seconds), the peak VO2 (in ml/kg/min), the anaerobic threshold (ml/kg/min) and pulse O2 (ml/beat). The ejection fraction and end systolic and end diastolic volumes were evaluated by M mode echocardiography. The results of the precited investigations were compared in survivors and patients who died. After 15 months, 7 patients had died and 36 survived, six of the patients who died were in NYHA Class IV. The peak VO2 was 10.1 ml/kg, the anaerobic threshold was 8.5 ml/kg and pulse 02 6.1 ml/beat in the patients who died compared to 17.6 ml/kg (p less than 0.001), 14.5 ml/kg (p less than 0.001) and 9 ml/beat (p less than 0.01) in the survivors. In addition, the ejection fraction was significantly lower in patients who died (24.7 +/- 8.3 versus 35.5 +/- 7.4%, p less than 0.001). Exercise capacity was therefore a predictive factor of mortality in cardiac failure. It is more discriminating than biological parameters such as natremia and serum adrenaline concentrations. However, these exercise stress parameters (VO2, anaerobic threshold) provide little complementary information with respect to the NYHA Classification in this study.