Impairment of ventilatory efficiency in heart failure - Prognostic impact

Background-Impairment of ventilatory efficiency in congestive heart failure (CHF) correlates well with symptomatology and contributes importantly to d yspnea. Methods and Results-We investigated 142 CHF patients (mean NYHA class, 2.6; mean maximum oxygen consumption [Vo(2)max], 15.3 mL O-2 . kg(-1) . min(-1) ; mean left ventricular ejection fraction [LVEF], 27%). Patients were compa red with 101 healthy control subjects. Cardiopulmonary exercise testing was performed, and ventilatory efficiency was defined as the slope of the line ar relationship of VCO2 and ventilation (VE), Results are presented in perc ent of age- and sex-adjusted mean values. Forty-four events (37 deaths and 7 instances of heart transplantation, cardiomyoplasty, or left ventricular assist device implantation) occurred. Among VO(2)max, NYHA class, LVEF, tot al lung capacity, and age, the most powerful predictor of event-free surviv al was the VE versus VCO2 slope; patients with a slope less than or equal t o 130% of age- and sex-adjusted normal values had a significantly better I- year event-free survival (88.3%) than patients with a slope >130% (54.7%; P <0.001). Conclusions-The VE versus VCO2 slope is an excellent prognostic parameter. It is easier to obtain than parameters of maximal exercise capacity and is of higher prognostic importance than VO(2)max.