Serial exercise performance in children with surgically corrected congenital aortic stenosis.

We examined serial exercise test performance in children with congenital aortic stenosis (AS) treated surgically compared to that of nonoperated children with mild to moderate AS. Maximal treadmill exercise data were assessed in 21 children 5.5 +/- 3.8 years after aortic valve (AO) surgery. Patients had undergone the Ross procedure (n = 6) or previous aortic valvotomy, balloon valvuloplasty, or neonatal aortic valvotomy (n = 15). Follow-up treadmill tests were conducted 3.7 +/- 2.8 years later. Data were compared to those of 19 nonoperated AS patients (mean gradient by echocardiogram <50 mmHg). These patients were exercised 3.6 +/- 3.2 years apart. Endurance time, heart rate, systemic blood pressure, and electrocardiogram were compared as repeated measures between tests and to age- and sex-matched normative data. Postsurgical children with AS had normal endurance times despite low peak heart rates on the initial test, and they maintained endurance over time. Nonoperated children with mean AO gradients <50 mmHg also had normal endurance times on the initial test but increased endurance over 3.6 years. Children with operated and nonoperated AS were able to reach or exceed normal endurance times, which may make it difficult to achieve compliance to imposed activity restrictions in this population.

Exercise studies in patients with transposition of the great arteries after atrial repair operations (Mustard/Senning): a review.

Exercise evaluation studies of patients after atrial repair surgery for transposition of the great arteries, as in tetralogy of Fallot, represent only a small fraction of the 3970 Medline references (1966 to mid-1997) concerning this congenital heart lesion. We have abstracted data from 27 studies from 20 institutions reporting on measurements during exercise on work capacity, heart rate response, respiratory gas exchange, or radionuclide/radiographic systemic ventricular ejection fraction measurements in addition to resting pulmonary function measurements. These studies provide almost uniform general conclusions that even after 20 or more years of follow-up (1) most patients "report" that they are asymptomatic in performing usual levels of physical activities; (2) significant abnormalities are present, often in more than half of the patients studied, in one or more of the exercise measurements when compared to control subjects; and (3) the diminished exercise performance is related to a diminished cardiac output, results from diminished stroke volume but is also related to a blunted heart rate response.

Pulmonary fibrosis and myositis in a child with anti-Jo-1 antibody.

This is the first report of a child with anti-Jo-1 antibody. At 10, she had a chronic cough, wheezing, dyspnea on exertion, a combined obstructive and restrictive ventilatory defect, and a decreased diffusion capacity compatible with alveolar fibrosis (lung biopsy). By age 12, she developed arthralgias, malar rash, frontal alopecia, Raynaud's phenomenon, and was seropositive for antinuclear antibodies, (SSA)Ro, Jo-1 and rheumatoid factor. At 16, symptomatic inflammatory myositis (elevated creatinine kinase, muscle biopsy) was documented with persistent anti-Jo-1. Her pulmonary symptoms have progressed despite appropriate therapy. Although her digits have become sausage shaped with swan neck deformities, joint pain is not frequent.

Carnitine metabolites in infants with cystic fibrosis: a prospective study.

Acylcarnitine is low in cord blood in patients with cystic fibrosis, suggesting that fatty acid metabolism is disturbed in utero. Carnitine metabolites (total, free, short- and long-chain acylcarnitine) were measured prospectively in 23 newly diagnosed infants with cystic fibrosis treated with a carnitine-containing, predigested formula for 6-12 months. Total (p < 0.002), free (p < 0.004), and long-chain (p < 0.001) plasma concentrations of carnitines were significantly less than controls (n = 48) at diagnosis. Total and free concentrations were corrected with nutritional management, whereas short- and long-chain acylcarnitines remained unchanged. By three years of age all plasma concentrations of carnitine metabolites were significantly less than controls despite a carnitine-containing diet. Urinary carnitine metabolites were increased at diagnosis and follow-up. The physiological significance of these observations in cystic fibrosis is unknown, but could be compatible with disturbed regulatory control with resultant increased utilization.

Heart rate and oxygen uptake response to exercise in children with low peak exercise heart rate.

Normal children achieve the same increase of oxygen uptake (VO2) in response to exercise even though resting and submaximal exercise heart rates vary greatly as a function of age, body size and physical conditioning. To determine whether the VO2 response to exercise is altered when heart rate is significantly reduced by heart disease, we compared 78 children who achieved a peak exercise heart rate of less than or equal to 150 beats/min to 201 controls of similar body size and normal peak exercise heart rates of greater than or equal to 180 beats/min. All performed incremental (16.4 Watts/min) maximal cycle exercise. Separate analysis of males and females included heart rate, power (kg-m/min, Watts/kg), VO2 (ml/min, ml/min per kg), O2 pulse (VO2/heart beat), VE (l/min) and R (VCO2/VO2) at rest and during the 1st, 4th and last minute of exercise. Patients with low peak exercise heart rates had also lower resting submaximal exercise heart rates than controls. VO2 at comparable exercise levels did not differ from controls and consequently O2 pulse was greater in the patients than controls at rest and at all levels of exercise. A consistent gender difference was only found in controls where males achieved a higher VO2 and lower heart rates at comparable levels of exercise. The data show a normal exercise VO2 despite significantly lower heart rates. These findings cannot be explained by an increased arteriovenous difference alone and suggest that the patients retained the ability to effectively modulate stroke volume.

Acylcarnitine is low in cord blood in cystic fibrosis.

Carnitine metabolites (total, free, short and long chain) were analyzed in cord blood of cystic fibrosis (n = 5), non-CF siblings (n = 7), and controls (n = 8). Total acylcarnitine (short and long chain combined) was significantly lower (less than 0.001) in CF compared to both control groups. Total and free carnitine showed no significant differences between the three groups. These findings are compatible with disturbed fatty acid metabolism in utero and may be related to the increased energy expenditure characteristic of CF infants.

Exercise response before and after termination of atrial tachycardia after congenital heart disease surgery.

We studied exercise performance before and after conversion of atrial tachycardia to sinus rhythm, atrial bradycardia, or junctional rhythm in 10 patients 9-25 years of age 8-20 years after congenital heart disease surgery (complete transposition of the great arteries, seven of 10 patients). The same maximal cycle (five of 10 patients) or treadmill (five of 10 patients) exercise protocol was performed in atrial tachycardia and sinus rhythm 1-232 days after atrial tachycardia (mean, 34 days). Electrocardiogram, heart rate, and pulmonary gas exchange were recorded. Sinus rhythm exercise increased peak VO2 (mean, 28.7 [sinus rhythm] vs. 24.7 [atrial tachycardia], p less than 0.01), exercise time (p less than 0.01), and O2 pulse at rest (p less than 0.01) and at peak exercise (NS). Mean resting heart rate decreased from 109 to 70 beats/min (p less than 0.01). In atrial tachycardia, peak exercise heart rate was low (80-163 beats/min) because of fixed conduction (six of 10 patients) or high as conduction approached 1:1 (176-252 beats/min) (four of 10 patients). In sinus rhythm, rest to peak exercise heart rate increased in six of 10 patients (p less than 0.05). The data show improved exercise performance in sinus rhythm primarily because of improved heart rate adaptation to exercise, by either permitting increased heart rate response or eliminating excessively high heart rate with inadequate diastolic filling.

Fat intake is low in cystic fibrosis despite unrestricted dietary practices.

A prospective study of caloric intake and specific nutrient composition was performed in 64 cystic fibrosis patients aged 0.3 to 18 yr. Linear regressions and multiple stepwise regressions revealed no significant correlations between any individual dietary parameter and age, height, weight, percentile of weight or height, Shwachman Score, and pulmonary parameters. The caloric intake varied widely in individual patients and in different age groups. Despite unrestrictive dietary practices, the fat intake (33.7% +/- 8) was below that recommended for these linoleate deficient patients.

Successful reinnervation of the diaphragm after phrenic nerve transection.

A 16-month-old infant presented with bilateral diaphragmatic paralysis and respiratory failure after removal of a thoracic teratoma. Right diaphragmatic function recovered after end-to-end anastomosis of a transected phrenic nerve. We conclude that phrenic nerve repair can restore diaphragmatic function and should be attempted in selected cases of diaphragmatic paralysis due to phrenic nerve injury.

Integrated cardiopulmonary approach to exercise testing in pediatrics.

In the pediatric age groups exercise evaluation of cardiac and pulmonary disease has had a lesser impact on clinical care than in adults. Exercise evaluation complements clinical information, echocardiography, hemodynamics and lung function studies at rest to provide reproducible, quantitative information to answer questions of capacity for physical work, employment, insurability and participation in recreation and sports. To ensure serial studies in children measurements should be noninvasive and minimize demands of patient cooperation. Exercise evaluation should include evaluation of lung function at rest to exclude pulmonary limitations of exercise. Because of the close link of cardiovascular and pulmonary responses to exercise, assessment of ventilation and pulmonary gas exchange should be an integral part of exercise evaluation. Computerized systems can enhance the accuracy and precision of such measurements and can provide a data base for evaluation of individual patients and the natural history of treated congenital cardiac defects and pulmonary disease.

Computed tomography diagnosis of bronchial compression by the spine after surgical correction of scoliosis.

Compression of the bronchi by vertebral bodies is an uncommon cause of atelectasis. This report describes a patient with such a compression and the important role of CT in establishing the etiology.

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.

Tetralogy of Fallot with absent pulmonary valve. Should valve insertion be part of the intracardiac repair?

Thirteen patients with complex of tetralogy of Fallot and absent pulmonary valve were treated. Three infants presented with severe cardiorespiratory distress (Group I) necessitating surgical intervention in two and intensive medical treatment in the third; there were no late survivals. The remaining 10 patients were operated upon electively at an older age (Group II); in six the ventricular septal defect was closed and the right ventricular outflow obstruction relieved (Group IIA), and in the other four a valve was inserted at the pulmonary anulus at the time of intracardiac repair (Group IIB). There was no hospital mortality in Group II. Five of the six patients in Group IIA remained symptomatic postoperatively, and three needed a subsequent pulmonary valve insertion. All patients in Group IIB were symptom free following operation; one patient began having a progressive decrease in exercise performance, decrease in pulmonary artery size, and cardiothoracic ratio were more marked in those patients who had primary insertion of a pulmonary valve. The clinical results and postoperative assessment of cardiac function tend to indicate that pulmonary valve insertion should be performed at the time of the intracardiac repair.