A radioisotope first pass study was done on patients over a period of 1 to 15 years (average 4.6 years) after repair for ventricular septal defect or arterial septal defect with a left to right shunt. The age of the patients ranged from 6 to 32 years (average 14.2 year) at the time of the study. The total work of exercise and the right and left ventricular ejection fraction(EF) were evaluated at rest and after exercise. The results were compared with the preoperative hemodynamic findings and with the age of patient at the time of the operation. 1) When the total work of exercise was divided with the maximal exercise capacity of the normal individual corresponding to the patients' height and body surface area (the percentage of total work), it were very low with the average of 40% of normal. There was no sexual difference, but the percentage of total work of exercise had significant correlation with the patients' age at the time of operation (r = -0.52,p<0.01) and post-exercise left ventricular ejection fraction (LVEF)(r = -0.39,p<0.05). 2) LVEF at rest had some correlation with the preoperative mean pulmonary arterial pressure (r = -0.29, p = 0.05), but showed no relationship with Qp/Qs or Rp/Rs ratios. The right ventricular ejection fraction (RVEF) at rest had no relations with the preoperative hemodynamic findings with maximal workload. 3) The post-exercise RVEF showed linear correlation with the preoperative Rp/Rs ratio (r = -0.49,p<0.005), and mean pulmonary arterial pressure (r = -0.37,p<0.05). The post-exercise LVEF had no significant correlation with any preoperative hemodynamic factors. 4) When greater than 5% increase in ventricular EF after exercise is considered normal, the group with the normal right and left ventricular responses (n = 11) showed normal preoperative Rp/Rs ratio (7.6 +/- 4.1). In the group with normal left, but abnormal right ventricular response (n = 9) and the group with abnormal biventricular response (n = 11), both demonstrated incremental increase in Rp/Rs ratio (20.1 +/- 11.3, 26.3 +/- 19.8 respectively). Normal right, but abnormal left ventricular reaction (n = 2) was noted in patients with residual aortic valvular insufficiency and residual ventricular septal defect. In conclusion, post-operative ventricular response was much more sensitive and informative than that of ventricular function at rest and to detect subclinical cardiac dysfunction. Post-exercise RVEF was closely correlated with preoperative pulmonary vascular hemodynamics, while post-exercise LVEF seemed to be a majo determinant of working capacity after repair.
Adolescent ; Adult ; Child ; Child, Preschool ; Exercise Test ; *Exertion ; Female ; Heart Defects, Congenital/*physiopathology/radionuclide imaging/*surgery ; Human ; Infant ; Male ; *Stroke Volume

OBJECTIVETo assess the feature of pulmonary blood flow distribution after total cavopulmonary connection (TCPC) of different types, and to provide the selection of the best type.

METHODSThirty-two consecutive survival patients after TCPC underwent radionuclide lung perfusion imaging. According to the radionuclide counts in the left and right lungs, analyses of the distribution of blood flow from superior venous cava (SVC) and inferior venous cava (IVC) and the whole pulmonary blood flow in both lungs were made. All patients were divided into 4 groups by the the anastomosis between IVC and pulmonary artery.

RESULTSGroup I: The flow ratio of the IVC to left lung was greater than that to the right lung, P < or = 0.01; the flow ratio of the SVC to right lung was greater than that to the left lung, P < or = 0.01; and the whole pulmonary blood flow went dominantly to the left lung, P < or = 0.05, which is not in line with physiological distribution. Group II: the flows from the SVC and IVC were mixed in the middle of the junction and ran evenly into the right and left lungs, the whole pulmonay blood flow went to both lungs, P > or = 0.05. Group III: the flow ratio of the SVC to both lungs were the same, P > or = 0.05, and major part from IVC went to the right lung, P < or = 0.01; the pulmonary blood flow go dominantly to the right lung, P < or = 0.05, which is in accord with physiological distribution. Group IV: the flows from the right SVC went to right lung by 100%, P < or = 0.01, and that from the left SVC went to left lung by 100% too, P < or = 0.01; the flows from IVC went dominantly to the left lung, with little part to the right lung, P < or = 0.05.

CONCLUSIONSDifferent types of TCPC can result in different pulmonary blood distributions. The best flow distribution between the left and right lungs can be obtained by an offset of the IVC anastomosis toward the RPA with widening anastomosis for the patients without persist left superior venous cava (PLSVC).

Adult ; Child ; Child, Preschool ; Female ; Fontan Procedure ; methods ; Heart Defects, Congenital ; physiopathology ; surgery ; Humans ; Lung ; blood supply ; diagnostic imaging ; Male ; Pulmonary Artery ; surgery ; Radionuclide Imaging ; Regional Blood Flow ; Vena Cava, Inferior ; surgery ; Vena Cava, Superior ; surgery