Lung function in tetralogy of Fallot after intracardiac repair.

Earlier studies have shown significant restrictive lung volume patterns in virtually all patients after shunt palliation and/or subsequent intracardiac repair (ICR) of tetralogy of Fallot. We have studied lung volumes and capacities, maximum voluntary ventilation (MVV), and maximum mid-expiratory flow (MEF[25-75]) at least 1 year after ICR in 123 patients, 91 males and 32 females, which included 54 who underwent primary ICR. All were evaluated by stress testing and 61 were studied serially from two to eight times at 12 to 18 months intervals. In contrast to the previous studies, we found a lower incidence and lesser degrees of restrictive lung volume patterns. Lung volumes may be entirely normal particularly after primary ICR but also when ICR is preceded by shunt palliation. After reoperation for ICR normal lung volumes are uncommon. These is a high correlation between abnormal lung volumes and poor surgical results of ICR as manifested by residual cardiac disease, notably pulmonic valve insufficiency and increased heart size. In primary repair we found no correlation between the presence of abnormal lung volumes and the age at ICR (range 1.87 to 15.4 years). Abnormal lung volumes correlate with reduced exercise performance, but the latter is limited by cardiovascular rather than pulmonary factors. Serial studies show stable lung volume patterns with time, and we found no evidence that the increased level of physical activity usually present after ICR results in increases of lung volumes in excess of those predicted from somatic growth. We conclude that an excellent surgical repair of tetralogy is the best guarantee against a significant restrictive lung volume pattern after repair.