LUNG-HEART INTERACTION AS A SUBSTRATE FOR THE IMPROVEMENT IN EXERCISECAPACITY AFTER BODY-FLUID VOLUME DEPLETION IN MODERATE CONGESTIVE-HEART-FAILURE

We investigated exercise capacity after fluid depletion in patients wi th moderate congestive heart failure (CHF). Twenty-one patients underw ent ultrafiltration (mean volume +/- SEM: 1,770 +/- 135 ml). Echocardi ography, tests of pulmonary function, and a cardiopulmonary exercise l est with hemodynamic and esophageal pressure monitoring were performed before ultrafiltration and 3 months later. Tests without invasive mea surements were repeated 4 and 30 days after ultrafiltration. Twenty-on e control patients followed the same protocol but did not have ultrafi ltration. Patients who underwent ultrafiltration and increased their o xygen consumption at peak exercise (peak VO2) by >10% at the 3-month e valuation (group A1, n = 9) were separated from those who did not (gro up A2, n = 8); 3 patients did not complete the follow-up. Four days af ter the procedure, peak VO2 had risen from 17.3 +/- 0.8 to 19.3 +/- 0. 9 ml/min/kg in group A1, and from 11.9 +/- 0.7 to 14.1 +/- 0.7 ml/min/ kg in group A2 (p <0.01). Plasma norepinephrine and pulmonary function were consistent with a greater severity of the syndrome in group A2. At 3 months in group A1, the relations of tilling pressure to cardiac index of the right and left ventricles were shifted upward; the esopha geal pressure swing (differences between end-expiratory and end-inspir atory pressure) for a given tidal volume was lower; the peak exercise dynamic lung compliance had increased from 0.10 +/- 0.05 to 0.14 +/- 0 .03 L/mm Hg (p <0.01). None of these changes were detected in group A2 and control patients. In moderate CHF, variations in lung mechanics a nd cardiac hemodynamics with body fluid volume withdrawal participate in the amelioration of the exercise performance; persistence of benefi ts is inversely related to the severity of CHF.