Causes of recoarctation after balloon angioplasty of unoperated aortic coarctation.

During the 35 month period ending December 1987, 30 children, aged 14 days to 13 years, underwent balloon angioplasty of unoperated aortic coarctation with resultant reduction in coarctation gradient from 43.6 +/- 20.4 to 9.5 +/- 7.6 mm Hg (p less than 0.001). None of the patients required immediate surgical intervention. On the basis of results of 6 to 30 month follow-up catheterization data in 20 children, the patients were classified as follows: Group A, 13 patients with good results (gradient less than or equal to 20 mm Hg and no recoarctation on angiograms) and Group B, 7 patients with fair or poor results (gradient greater than 21 mm Hg with or without recoarctation on angiography). No patient developed aortic aneurysm at the site of angioplasty. Thirty variables were examined by multivariate logistic regression analysis and four factors were identified as risk factors for development of recoarctation: 1) age less than 12 months, 2) aortic isthmus less than 2/3 the size of the ascending aorta immediately proximal to the right innominate artery, 3) coarcted aortic segment less than 3.5 mm before dilation, and 4) coarcted aortic segment less than 6 mm after angioplasty. The identification of risk factors may help in selection of patients for balloon angioplasty. Avoiding or minimizing the number of risk factors may help reduce the chance of recoarctation after angioplasty. The intermediate-term follow-up results with regard to recoarctation are comparable with those after surgical repair of coarctation. Recoarctation after angioplasty was dealt with by repeat balloon angioplasty or surgical resection for those requiring treatment and clinical follow-up for the remaining children.(ABSTRACT TRUNCATED AT 250 WORDS)

Intermediate-term follow-up results of balloon aortic valvuloplasty in infants and children with special reference to causes of restenosis.

Sixteen infants and children with valvular aortic stenosis underwent percutaneous balloon aortic valvuloplasty over a 36-month period ending August 1988. The mean systolic pressure gradient across the aortic valve decreased from 72 +/- 21 (mean +/- standard deviation) to 28 +/- 13 mm Hg (p less than 0.001) immediately after valvuloplasty; the degree of aortic insufficiency did not significantly increase. Follow-up catheterization (in 10 patients) and Doppler data (in all 16 patients) were available 3 to 32 months (mean 12 months) after valvuloplasty and revealed a residual aortic valvular gradient of 37 +/- 23 mm Hg, which continues to be significantly lower (p less than 0.001) than that before valvuloplasty. There was no increase in aortic insufficiency. On the basis of follow-up data, the 16 children were divided into 2 groups: group I with good results (gradients less than or equal to 49 mm Hg), 12 patients; and group II with poor results (gradients greater than or equal to 50 mm Hg), 4 patients. All 4 patients in group II required repeat balloon valvuloplasty or surgical valvotomy; none from group I required these procedures. Seventeen general, anatomic, physiologic and technical variables were examined by a multivariate logistic regression analysis to identify factors associated with restenosis; these risk factors were: age less than or equal to 3 years; and immediate aortic valvular gradient after valvuloplasty greater than or equal to 30 mm Hg. The immediate and intermediate-term follow-up results of balloon aortic valvuloplasty are encouraging. Recognition of the risk factors may help identify potential candidates for recurrence.(ABSTRACT TRUNCATED AT 250 WORDS)

Repetitive ventricular responses to ventricular extrastimulation studies in children and adolescents.

The effect of single premature ventricular extrastimuli during ventricular pacing was evaluated in 22 children with a mean age of 8.8+/-5.8 years. A repetitive ventricular response (V(3)) was observed at a critical coupling interval of prematurity in 10 of 22 children (45%). This response was similar in morphology and axis orientation to the premature and paced beats and was preceded by a His bundle depolarization. The V(3) response occurred nearly as frequently in patients without ventricular dysrhythmias as in those with ventricular dysrhythmias. The V(3) response is a normal phenomenon during ventricular stimulation.

Effect of age and heart rate on the conduction of the sinus node impulse to the ventricle.

The PR interval of the electrocardiogram is made up of the conduction intervals through the atrial muscle, the atrioventricular node, the bundle of His, and the bundle-branch and Purkinje fibers. Knowledge of normal conduction intervals and their relationship to age and sinus cycle length is important for the purpose of defining conduction delays at various sites. We analyzed intracardiac conduction intervals in 70 children with normal hearts, or with insignificant congenital heart lesions, who had been studied over the last 7 years. Linear and multilinear regressions were made, with age and sinus cycle length as the independent variable and the conduction interval as the dependent variable. The PR interval and intraatrial and AV node conduction times had a small but statistically significant positive correlation with age and were independent of sinus cycle length. The conduction time in the His-Purkinje system was not dependent upon either age or sinus cycle length. (The sinus cycle length increases with age.) By using mean values and two standard deviations, the normal range for intraatrial conduction was 2 to 38 msec; for AV node conduction, the range was 44 to 112 msec; and for the His-Purkinje conduction, the range was 23 to 55 msec.

The rare association of tetralogy of Fallot with hypertrophic cardiomyopathy. Report of 2 neonatal patients.

Although tetralogy of Fallot is commonly associated with other congenital heart defects, it is rarely found in conjunction with hypertrophic cardiomyopathy. We describe the cases of 2 neonates with this rare condition, both of whom required surgical intervention during infancy. Because hypertrophic cardiomyopathy is frequently familial, and tetralogy of Fallot is commonly found in patients diagnosed with chromosomal anomalies, we speculate about a possible genetic cause for this association.

Significance of infundibular obstruction following balloon valvuloplasty for valvar pulmonic stenosis.

This study was designed to define the prevalence and significance of infundibular obstruction following balloon pulmonary valvuloplasty. Thirteen of 62 children had infundibular gradients prior to valvuloplasty; five of these disappeared following balloon valvuloplasty. Five other children without pre-valvuloplasty infundibular gradients but with angiographic infundibular narrowing developed new infundibular gradients following valvuloplasty. Propranolol was administered to six children because of severe infundibular constriction, with improvement. None required surgical intervention. At follow-up the infundibular gradients either diminished or disappeared. The infundibular gradients appear to be more frequent with increasing age and severity of pulmonary valvar obstruction. Children developing systemic or suprasystemic right ventricular pressures after balloon pulmonary valvuloplasty may be candidates for propranolol therapy. Regression of the infundibular stenosis at follow-up can be expected, as has been observed after surgical pulmonary valvotomy. Because the infundibular obstruction can be successfully managed, balloon pulmonary valvuloplasty remains the treatment of choice for isolated valvar pulmonary stenosis. Use of balloon valvuloplasty in children less than 5 years of age and/or prior to development of pulmonary gradients in excess of 80 mm Hg may reduce the chance for development of infundibular reaction.

Use of propranolol for severe dynamic infundibular obstruction prior to balloon pulmonary valvuloplasty (a brief communication).

A case of severe pulmonary valvar stenosis and infundibular obstruction has been reported. Infundibular obstruction was so severe that no catheter could be advanced into the pulmonary artery. Propranolol, 0.5 mg given intravenously, reduced the obstruction and allowed the balloon dilatation of the pulmonary valve to be carried out without complication. Subsequently oral propranolol helped to remove the infundibular obstruction. We strongly recommend the use of propranolol when infundibular obstruction is present prior or after the balloon pulmonary valvuloplasty.

Dual atrioventricular nodal pathways: a common electrophysiologic response in children.

Electrophysiologic investigation was performed on 61 children and young adults during evaluation of either cardiac dysrhythmia or pre- or postoperative congenital heart disease. The results of these studies were reviewed retrospectively to determine if longitudinal dissociation of the atrioventricular node (AVN) was present. Dual AVN pathways were detected by the atrial extrastimulus technique, using His bundle electrograms. A discontinuous H1H2 response curve indicated the presence of dual AVN pathways. There was a higher incidence of dual AVN pathways in patients with clinically evident paroxysmal supraventricular tachycardia (PSVT) than in those without PSVT. Dual AVN pathways were equally prevalent in children with corrected and uncorrected congenital cardiac defects.

Urban outbreak of goat cheese brucellosis.

In 1983 an outbreak of human brucellosis caused by Brucella melitensis occurred among residents of a predominantly Hispanic neighborhood in Houston, TX. The source of the infections was traced to unpasteurized goats' milk cheese imported from Mexico. Nineteen of the 31 patients who contracted the disease were members of 5 families, which included 11 children ranging in age from 2 to 17 years. Infection was generally associated with protein complaints and a paucity of physical findings. Both immunoglobulin M and immunoglobulin G agglutinins were present in acute phase sera in the majority of patients, and low titers of immunoglobulin M antibodies remained in the sera of 43% who were retested 2 years later. Trimethoprim-sulfamethoxozole was highly effective in the treatment of children with brucellosis and was associated with no relapses.