Haemodynamic response to dynamic exercise after heart-lung transplantation

The purpose of this study was to investigate the haemodynamic response to d ynamic exercise after heart-lung transplantation (HLT). Nine stable HLT recipients (6 males) were studied 12-55 months after transp lantation, While sitting on a cycle ergometer, they first underwent a maxim al symptom-limited exercise test (power increment was 10 W.min(-1)) to dete rmine the maximal tolerable workload, On the next day, they performed a sec ond exercise test at 0, 40, 60 and 80% of their predetermined maximal workl oad (mean+/-SD: 108+/-20 W). Stage duration was 6 min. Respiratory, gas exc hange, and haemodynamic measurements were performed at rest, during the las t minute of each stage, and after recovery. Haemodynamic variables at rest were within normal limits except heart rate (HR) which was greater and stroke volume index (SVI) which was lower than n ormal. Peak oxygen consumption was 61+/-8% of predicted. KR showed an initi al slow increase followed by a steeper rise, and a delayed return to baseli ne during the recovery period. SVI and cardiac index (CI) increased at the onset of exercise but did not change significantly at 40-80% of the maximal workload. Pulmonary capillary wedge pressure increased from 4+/-2 mmHg at rest to 14+/-3 mmHg at maximal exercise. It is concluded that during dynamic exercise, heart-lung transplantation re cipients demonstrate a chronotropic incompetence, a reduced increase in car diac index and stroke volume index, and an excessive rise in left ventricul ar filling pressures. These alterations may contribute to the persistent ex ercise limitation.