Haemodynamic findings at rest and during exercise before and after operation in 18 patients

Summary The results from haemodynamic investigations at rest and during exercise in 18 patients before and 11 months, on the average, after surgical repair of ASD sec are reported. One patient had pulmonary hypertension before the operation, but the values for the remaining patients did not deviate essentially from those reported for the whole series. Since the exercise tests were performed with the same work loads before as after operation, individual comparisons of the haemodynamic results could be made. The heart rate and oxygen uptake were the same postoperatively as pre‐operatively, both at rest and during exercise. An approximate evaluation of the magnitude of the left‐to‐right shunt during exercise was made by comparison between the pre‐ and postoperative flow conditions in the systemic and pulmonary circulations; the shunt appeared to remain unchanged by exercise. A tendency to hypokinetic circulation was observed postoperatively, and this was probably more pronounced before the operation. The distensibility index for the right ventricle was significantly higher (**) preoperatively than postoperatively, both at rest and during exercise; at rest, this index was significantly higher (***) for the right than for the left ventricle, both pre‐ and postoperatively. A more accurate indication of the mechanical efficiency of the ventricles was the work index. This was significantly lower (***) postoperatively for the right ventricle, and this indicated satisfactory restitution of the ventricular function despite the preoperatively greatly increased work load for the ventricle. The pressures at rest, pre‐ and postoperatively, agreed with previously reported values for normal persons. The pulmonary vascular resistance values lay, on the average, within the normal limits both at rest and during exercise, but preoperatively they were usually low and postoperatively somewhat higher. During exercise, however, an abnormal increase of the pulmonary vascular resistance was noted in half of the patients. There was no relationship, however, between this reaction and either physical work capacity, preoperative shunt or heart size. There was no statistically significant correlation either between the preoperative values of shunt index and heart volume or between their postoperative reductions.