Ventilatory efficiency predicts risk for major cardiac events

Kaplan-Meier analysis for two-year major cardiac-related events. Subjects meeting criteria for VC-1 (VE/VCO₂ slope ≤29.9; n = 144) experienced four major cardiac events (including two heart transplants); 97.2% were event-free. Subjects meeting VC-II criteria (VE/VCO₂ slope 30 to 35.9; n = 149) experienced 22 major cardiac events (including three LVAD implantations); 85.2% were event-free. Subjects meeting VC-III criteria (VE/VCO₂ slope 36 to 44.9; n = 112) experienced 31 major cardiac events (including three LVAD implantations and two heart transplants); 72.3% were event-free. Subjects who met VC-IV criteria (VE/VCO₂ slope ≥45; n = 43) experienced 24 major cardiac events (including two LAVD implantations and five heart transplants); 44.2% were event-free. Log-rank 86.8, p<0.0001.