Early recovery cardiopulmonary parameters after exercise testing as predictors of mortality in CHF patients

Patients (pts) with chronic heart failure (CHF) are characterized by a prolonged early recovery of Vo2 and heart rate (HR) kinetics after exercise that reflects an increased oxygen debt and an attenuation of parasympathetic tone during early recovery period. Aim of this study was to evaluate the prognostic significance of these abnormalities in CHF pts. Eighty-one (74M/7F) CHF pts underwent incremental symptomlimited cardiopulmonary exercise testing (CPET) on treadmill. Early recovery of HR and Vo2 kinetics was evaluated by HR-recovery (HRR), defined as HR difference from peak exercise to 1 min after exercise (“abnormal” if HRR was 12b/min) and by half-time [T1/2, (min)] of Vo2 peak decay as time required for a 50% fall from Vo2 peak (“abnormal” if T1/2 was 1.3 min). Exercise capacity was evaluated by Vo2 peak, anaerobic threshold (AT) and VE/VCO2 slope. Pulmonary capillary wedge pressure (PCWP) and left ventricular ejection fraction (LVEF) were also calculated. Pts were followed-up for 21 1 months and the primary end-point was cardiac mortality. Eighteen (17M/1F) pts (22.2%) died from cardiac events during the follow-up period. Non-survivors had a lower HRR and a higher T1/2, than survivors (11.4 6.4vs20.6 8.1;p 0.001and1.7 0.8vs1.4 0.6;p 0.03, respectively). Assessing a multivariate survival analysis among previous noted prognostic parameters as Vo2 peak ( or 14ml/kg/min), AT ( or 11ml/kg/min), PCWP ( or 12mmHg), LVEF ( or 35%), VE/ VCO2 slope ( or 34), NYHA (I,II vs III,IV) and T1/2 ( or 1.3min), only T1/2 was an independent predictor of mortality (OR:4.5;95%IC:1.3– 15.4;p 0.02). When HRR ( or 12b/min) was included in the above multivariate model, it was found to predict either independently mortality (OR:7.9;95%IC:3–21.1;p 0.001).Both HRR and T1/2 of Vo2 peak decay after exercise are significant prognostic parameters in risk stratification of CHF pts.