SHORT-TERM REPRODUCTIBILITY OF CARDIOPULMONARY MEASUREMENTS DURING EXERCISE TESTING IN PATIENTS WITH SEVERE CHRONIC HEART-FAILURE

Eleven men with severe chronic heart failure (peak cardiac index 4.0 /- 0.2 L/m(2)/min), six on a heart transplantation wait list, were pro spectively assessed. To determine reproducibility of cardiopulmonary a nd hemodynamic variables for clinical purposes during ramp bicycle erg ometry, the patients underwent two ramp bicycle ergometer tests (3 min utes unloaded, work rate increments of 12.5 W/min) with a 1-week inter val between tests, Oxygen uptake (VO2) carbon dioxide production (VCO2 ), and ventilation were measured breath by breath, and calculations we re performed to determine gas exchange ratio, oxygen pulse, ventilator y equivalents of oxygen and carbon dioxide, and end-tidal partial pres sure for oxygen and carbon dioxide. Additionally, heart rate, blood pr essure, and lactate levels were assessed. Measurements were performed at submaximum work rate levels of 25 W, 50 W, and 75 W at ventilatory threshold and at peak work rate. At all measurement points, the coeffi cient of variation for cardiopulmonary variables was between 1.4% and 71% for submaximum work rate levels, between 1.2% and 4.4% at ventilat ory threshold, and between 2.4% and 7.1% at peak work rate. For heart rate, blood pressure, and lactate levels, coefficient of variation was between 2.7% and 5.7% for submaximum work rate levels, between 1.4% a nd 6.1% at ventilatory threshold, and between 1.2% and 5.5% at peak wo rk rate. The data suggest high reproducibility for duplicate measureme nts of cardiopulmonory and hemodynamic variables during ramp bicycle e rgometry in patients with severe chronic heart failure. The results ma y be used to determine whether any variable in a single patient is sig nificantly different from that obtained in a previous exercise test or if the change is within experimental error.