PREDICTORS OF RESPONSE TO EXERCISE TRAINING IN SEVERE CHRONIC CONGESTIVE-HEART-FAILURE

We prospectively assessed whether baseline central hemodynamics and ex ercise capacity can predict improvement of (V)over dot O-2 at ventilat ory threshold (VT) after exercise training in patients with severe chr onic congestive heart failure. Eighteen patients (mean +/- SEM; age 52 +/- 2 years), half of them listed for transplant, underwent 3 weeks o f exercise training (interval cycle and treadmill walking; 5 x/week) a nd 3 weeks of activity restriction in a random-order crossover trial. Baseline data were nor significantly different for groups with exercis e training first and activity restriction first: cardiac index at rest (2.1 +/- 0.1 L/m(2)/min), maximum cardiac index (3.1 +/- 0.2 L/m(2)/m in) (Fick), and echocardiographic ejection fraction (21 +/- 1%). The s ame was true for cardiopulmonary exercise data (cycle ergometry; up ar row 12.5 W/min): (V)over dot O-2 at VT (9.3 +/- 0.4 ml/kg/min), maximu m (V)over dot O-2, (12.2 +/- 0.7 ml/kg/min), VT in percentage of predi cted maximum (V)over dot O-2 (31 +/- 2%), heart rote at VT (95 +/- 4 b eats/ min), and decrease of dead space-to-tidal volume ratio from rest to VT (33 +/- 1 --> 29 +/- 1). Improvement of (V)over dot O-2 at VT a fter training (2.2 +/- 0.4 ml/kg/min; p <0.001) was not related to bas eline central hemodynamics (r = <0.10 for each), but was greater in pa tients with a lower baseline (V)over dot O-2 at VT (r = -0.65; p <0.01 ), peak (V)over dot O-2 (r = -0.66; p <0.01), VT in percentage of pred icted maximum (V)over dot O-2, (r = -0.74; p <0.001), heart rate at VT (r = -0.63; p <0.01), and smaller decrease of dead space-to-tidal vol ume ratio from rest to VT (r = 0.65; p <0.01). Ejection fraction after exercise training (24 +/- 2%) and activity restriction (23 +/- 2%) di d not differ significantly compared with baseline, and patient status (heart failure and cardiac rhythm) remained stable. Three parameters a ccounted for 84% of the variance of improvement in (V)over dot O-2 at VT: (V)over dot O-2 at VT in percent predicted maximum (V)over dot O-2 , decrease of dead space-to-tidal volume ratio, and heart rate at VT. The findings suggest that there was a greater increase in (V)over dot O-2 at VT after exercise training in patients with greeter peripheral deconditioning at baseline. The improvement was unrelated to central h emodynamics. Clinically stable patients with severe chronic congestive heart failure, potential heart transplant candidates, and those await ing transplantation may benefit from involvement in a short-term exerc ise training program. (C) 1997 by Excerpta Medica, Inc.