Pulmonary venous obstruction and atrioventricular canal anomalies: role of cor triatriatum and double outlet right atrium.

Two-dimensional echocardiographic findings and surgical repair in three infants with atrioventricular (AV) canal and pulmonary venous obstruction are described. The AV canal was complicated by cor triatriatum in two patients and by double outlet right atrium in the other. In patients with AV canal, anatomic obstruction of pulmonary venous return should be excluded by detailed cardiac ultrasound examination.

Potentially fatal cardiac dysrhythmia and hyperkalemic periodic paralysis.

An 11-year-old boy was evaluated for mild periodic muscular weakness exacerbated on separate occasions by disopyramide phosphate and procainamide. He and his mother both had bidirectional ventricular tachydysrhythmia (BVT), short stature, microcephaly, and clinodactyly. The mother, but not the child, had lingual myotonia. The two antiarrhythmic drugs worsened the muscular weakness without benefiting the cardiac dysrhythmia. Potassium loading produced skeletal muscle weakness and transient conversion of the BVT to normal sinus rhythm. Hypokalemia aggravated the BVT without causing weakness. Acetazolamide had no effect. The patient suffered a nonfatal cardiac arrest after several days of increased carbohydrate intake. Imipramine controlled the dysrhythmia without inducing weakness. Periodic paralysis should be considered as the diagnosis in children with BVT, a potentially fatal condition.

Postoperative assessment of porcine-valved right ventricular-pulmonary artery conduits.

Insertion of extracardiac right ventricular (RV)-pulmonary artery (PA) conduits for repair of severe forms of RV-PA discontinuity has become a widely used technique. During a 10-year period, 76 patients had open heart repair with a porcine-valved RV-PA external conduit. The most common diagnoses were truncus arteriosus (15%) and pulmonary atresia with ventricular septal defect (15%). The patients were 18 days to 37 years old (median 7 years). The postoperative median follow-up period was 4 years. Four patients (8%) have been lost to follow-up. Nineteen patients (25%) died in the early postoperative period and there were 10 late deaths (13%). Calculated probability of survival was 66% at 8 years. Thirty-six patients have undergone late hemodynamic studies. A residual shunt was present in 14% of the patients; moderate to severe PA hypertension was present in 25% and significant RV-PA gradients (greater than 30 mm Hg) in 50%. The mean RV pressure for the group was 78.5 +/- 38 mm Hg. The severity of the gradients appeared to be greater in patients who had been followed longer. Ten patients have undergone reoperation because of conduit obstruction or residual shunting; 6 are alive and well. Of the surviving patients, 95% are acyanotic and without significant exercise intolerance and only 5% have cardiovascular symptoms. Thus, open heart repair using an external RV-PA conduit provides a marked improvement in the quality of life in patients who survive.

Method for recording electrical activity of the sinoatrial node and automatic atrial foci during cardiac catheterization in human subjects.

A method for recording electrical activity of the sinoatrial (S-A) node and automatic atrial foci in human subjects is described. To record S-A nodal electrograms, an electrode catheter was inserted percutaneously into the femoral vein and advanced under fluoroscopic control to the superior vena caval-right atrial junction. The distal terminal of the catheter was placed in the area of the S-A node and the proximal terminal on the free right atrial wall or in the right atrial lumen. Polarity was reversed from the conventional electrocardiographic recording; high amplification (about 100 microV/cm) and selective filters (0.1 to 20 hertz) were used. S-A nodal electrograms recorded with this method in human subjects were similar to electrograms obtained previously from the dog and rabbit and revealed negatively directed diastolic and upstroke slopes preceding the P wave of the electrocardiogram. Sinoatrial conduction time measured from the S-A nodal electrograms in 15 cases was 34.9 +/- 2.1 ms(mean +/- standard error of the mean) for a sinus cycle length of 736.4 +/- 38.6 ms. The coronary sinus electrograms in a patient with coronary sinus rhythm were recorded by the same technique except that the distal terminal of the catheter was placed at the coronary sinus ostium. A negatively directed diastolic slope preceding the P wave was consistently recorded. This method for recording electrograms of the S-A node and ectopic automatic atrial foci should prove useful in (1) assessment of both normal and abnormal S-A nodal function, (2) direct determination of conduction time from the S-A nodal pacemaker to the atrium, and (3) localization of automatic atrial foci.

Cardiovascular malformations in the fetal alcohol syndrome.

Cardiovascular anomalies are a frequently reported feature of the fetal alcohol syndrome, but only rarely have such children been catheterized. This article fully described the cardiac anomaly in two infants with this syndrome. The malformations found in both cases include a ventricular septal defect, and the rather unusual finding of pulmonary artery dysplasia.

Comparison of the cardiocirculatory effects of exercise and isoproterenol in children with pulmonary or aortic valve stenosis.

Isoproterenol infusion during cardiac catheterization as a simulator of exercise was evaluated with hemodynamic studies in children with pulmonary (15) or aortic (8) valve stenosis. Cardiac function was monitored during rest, mild exercise and isoproterenol infusion. Similar heart rates were maintained in both procedures. Peak pulmonary and aortic valve gradients as well as right and left ventricular dp/dt/p were significantly higher and cardiac index significantly lower with isoproterenol as compared to exercise. Isoproterenol induced a significantly greater decrease in systemic vascular resistance, and systemic blood pressure than did exercise. Left ventricular systolic pressure rose to similar levels and this resulted in substantially higher peak aortic gradients with isoproterenol. A consistent correlation was observed for peak valvular gradients measured during exercise and isoproterenol in both groups of patients. Accordingly, regression equations were obtained allowing reasonably accurate prediction of exercise valvular gradients on the basis of the isoproterenol data.

Persistence of the fetal circulation: radiologic considerations.

Persistence of the fetal circulation is a recently recognized cause of severe cyanosis in newborn full term infants. Abnormally elevated pulmonary vascular resistance apparently stimulated by hypoxia, acidosis, and/or hyperviscosity results in cyanosis due to large right-to-left shunts through persistent fetal channels (patent foramen ovale and patent ductus arteriosus). Initial chest radiographs demonstrate clear lungs, decreased, normal, or mildly prominent pulmonary vascularity, and normal to moderately enlarged cardiac silhouettes. Angiocardiography, when required to rule out cyanotic congenital heart disease, demonstrates normal intracardiac anatomy, normal great vessel relationships, and right-to-left shunting across the patent foramen ovale and patent ductus arteriosus. Significant tricuspid regurgitation occurs in some of these infants, associated with variable right ventricular dilatation; the left ventricle is normal. The majority of babies with this condition ultimately survive. Treatment consists of intensive care including oxygen therapy and correction of acidosis. Vasodilators such as tolazoline may be helpful.

Reversibility of chronic obstructive lung disease in infants following repair of ventricular septal defect.

The signs of obstructive lung disease dominated the clinical course of ten infants with ventricular septal defects and large left-to-right shunts. Airway obstruction in these patients can be attributed (1) to increase in large airway resistance as the result of compression by enlarged pulmonary arteries or cardiac chambers and (2) to increase in small airway resistance as the result of accumulation of peribronchiolar fluid. The rapid regression of the signs of obstructive airway disease following open heart repair of the ventricular septal defect indicates that the lung disease observed in these infants is secondary to the ventricular septal defect, rather than a primary process. The most effective management in the refractory patients is that of open repair of the defect.

Radiation exposure to the pediatric patient during cardiac catheterization and angiocardiography. Emphasis on the thyroid gland.

Thermoluminescent dosimetry was used to measure the radiation exposure to the skin, thyroid and gonads in 50 consecutive pediatric patients undergoing cardiac catheterization and angiocardiography using cine photofluorography. Average exposures were 17.1 R to the skin, 2.3 R to the thyroid and 0.1 R to the gonads. Fluoroscopy accounted for approximately 80% of the skin and thyroid exposure and cine photofluorography for 20-25%. Occasional primary-beam irradiation was the major contributor to gonad exposure. Internal scatter of the incident x-ray beam was primarily responsible for thyroid exposure, so that infants received relatively high exposures; one receiving 7.3 R. The thyroid was not frequently in the primary beam. The significance of high radiation exposure to the thyroid, and in particular its relationship to thyroid carcinoma, are discussed. The results are compared with other series in the literature and relative exposures of cine photofluorography and serial filming are contrasted.

Accessory mitral valve tissue causing left ventricular outflow tract obstruction in D-transposition of the great arteries.

Two patients with D-transposition of the great arteries (D-TGA) were found to have an unusual form of left ventricular outflow tract obstruction. Both had ball-like accessory mitral valve tissue that partially occluded the outflow tract. In one patient there was an intact septum, while in the other there were ventricular septal defects. The appearances have been described previously, although not in D-TGA. Recognition of accessory mitral valve tissue may allow resection of the tissue at the time of repair of the transposition complex.

Pacemaker implantation in children: a 21-year experience.

Forty-one children, 20 boys and 21 girls, aged 11 days to 19 years (mean 9.9 years) at initial pacemaker implant, were followed 1 to 248 months (mean 90 months). Ten (mean age 8.2 years) were implanted between 1966 and 1972 (Group I), 14 (mean age 9.9 years) between 1973 and 1980 (Group II) and 17 (mean age 10.9 years) from 1981 through April 1988 (Group III). Arrhythmias were congenital complete heart block in 19, postoperative heart block in 15, acquired heart block in 3, sick sinus syndrome in 3, and bradycardia-induced ventricular fibrillation in 1. Twenty-eight of 41 children had a transvenous implant: 40% of Group I, 71% of Group II and 82% of Group III. Thirteen were cephalic, four subclavian and 11 jugular. Generator site was pectoral in 19, abdominal in 12, intrathoracic in one, and retromammary in nine of 12 girls aged 10 years or more at implant. In Groups I, II and III, 5, 14 and 6 had VOO or VVI units; 5, 0 and 8 dual chamber (VAT, VDD and DDD) pacemakers; 0, 0 and 1 AAI; and 0, 0 and 2 rate-modulated (VVIR) units at initial implant. The average interval between pacer-related hospitalizations in Groups I, II and III was 20, 42, and 39 months. Complications included infection in six, hemothorax in one, and impending pacemaker erosion in one. Six patients died, one of pacer infection, four from primary cardiac disease, and one suddenly without apparent reason. Follow-up continues in 31: 14 are employed full-time, three are homemakers, eight are full-time students, and six are active pre-schoolers.(ABSTRACT TRUNCATED AT 250 WORDS)

"Bedside" balloon septostomy in infants with transposition of the great arteries: new concepts using two-dimensional echocardiographic techniques.

We performed balloon atrial septostomies in six successive infants with transposition of the great arteries, using echocardiographic guidance at the bedside in the neonatal intensive care unit. In all cases adequate septostomy was obtained and instantaneously assessable. PaO2 values increased as expected (mean before septostomy 28 mm Hg; after, 42 mm Hg). In cases of transposition clearly diagnosed echocardiographically, this intervention need not be done in the catheterization laboratory. The need for a full hemodynamic study in the neonatal period is arguable.

Subpulmonary obstruction in congenitally corrected transposition of the great arteries due to ventricular membranous septal aneurysms.

The clinical, hemodynamic, and angiographic observations, as well as the surgical approach used for repair in three patients with congenitally corrected transposition of the great arteries and ventricular membranous septal aneurysms, are presented. In two of the three patients the membranous septal aneurysm caused subpulmonary obstruction, with 94 and 125 mm Hg systolic gradients. In each patient the aneurysm was demonstrated by angiocardiography, which also showed differences in size and shape with cardiac systole and diastole. Review of the previously described reports indicates that patients with congenitally corrected transposition often display various forms of pulmonary outflow obstruction and when a ventricular membranous septal aneurysm exists, a significant subpulmonary obstruction is present in most patients. The unique anatomic relationship between the pulmonary artery and a ventricular membranous septal aneurysm in patients with transposition of the great arteries with and without atrioventricular discordance explains why subpulmonary obstruction sometimes develops.

Postoperative left anterior hemiblock and right bundle branch block following repair of tetralogy of Fallot. Clinical and etiologic considerations.

Previous reports have indicated an incidence of right bundle branch block (RBBB) and left anterior hemiblock (LAH) pattern varying from 8-22% following corrective surgery in patients with tetralogy of Fallot. Among 207 patients with tetralogy of Fallot operated on at our institution, 8.7% developed an ECG pattern of RBBB and LAH. These patients were followed for 1-13 years (mean 6.2 years) for a total of 111 patient years. All patients are alive and none have had documented late atrioventricular dissociation, syncope, or other symptoms. Transient heart block was present in one patient in the immediate postoperative period but has not recurred. This group of patients differs significantly from other series in which such an ECG pattern was associated with a marked increase in morbidity and mortality. These data and the experimental evidence suggest that two distinct groups of patients exist: 1) a group in which this ECG pattern is secondary to lesions within the bundle of His and 2) a group in which the pattern is caused by lesions in the peripheral conduction system. It is postulated that these two groups which demonstrate the same ECG pattern may carry significantly different prognoses. Analysis of H-V intervals postoperatively may help identify patients at risk.

Relation of arachidonate metabolites to abnormal control of the pulmonary circulation in a child.

To evaluate the role of arachidonate metabolites in regulating pulmonary vascular tone, we performed multiple studies on a 17-month-old girl with idiopathic pulmonary hypertension, systemic arterial hypoxemia (due to ventilation-perfusion mismatching), and an elevated thromboxane A2 (TXA2) to prostacyclin (PGI2) ratio due to increased TXA2 (measured as their stable metabolites, TXB2 and 6-keto-PGF1 alpha, respectively). Intravenous infusions of PGI2 reduced mean pulmonary arterial pressure (from 80 to 47 mmHg), increased cardiac output (from 3.43 to 3.97 L/min), increased systemic arterial oxygen saturation (from 60 to 72 percent), and decreased the TXB2 to 6-keto-PGF1 alpha ratio (from 5.9 to 0.2); mean systemic arterial pressure was unchanged. Pharmacologically decreasing the TXB2 to 6-keto-PGF1 alpha ratio with administration of nifedipine or diltiazem also reduced pulmonary hypertension and increased systemic arterial oxygen saturation in this patient. Nifedipine and diltiazem decreased the ratio by decreasing TXB2. Prostacyclin decreased the ratio by increasing 6-keto-PGF1 alpha. These studies support the hypothesis that the balance between TXA2 and PGI2 is an important influence on pulmonary vascular tone.