Pedro L. Ferrer

Dual atrioventricular nodal pathways: A benign finding in arrhythmia-free children with heart disease

The incidence and significance of dual atrioventricular (A-V) nodal pathways are described in 78 children with associated congenital or acquired heart disease. None of these patients had clinical or electrocardiographic evidence of arrhythmia. Dual A-V nodal pathways were observed in 35 percent of the preoperative group and in 33 percent of the postoperative group. Despite this substrate for A-V nodal reentry, supraventricular tachycardia was neither induced during electrophysiologic evaluation nor did it develop clinically over a follow-up period of 1 month to 15 years. It is concluded that dual A-V nodal pathways are common and may be a benign finding in arrhythmia-free children with heart disease.

Left isomerism and complete atrioventricular block: A report of six cases☆

Six children, aged 12 days to 13 years, with left isomerism and complete atrioventricular (A-V) block are presented. In all six patients the diagnosis of left isomerism was suggested by an interrupted inferior vena cava found during cardiac catheterization and angiocardiography; four patients had complex heart disease consisting of endocardial cushion defect, five had a common atrium, three had pulmonary stenosis, three had patient ductus arteriosus and two had dextrocardia. Further anatomic abnormalities included situs inversus of the viscera (four patients) as well as partial malrotation of the bowel. Of the six patients, four had congenital complete A-V block, whereas the remaining two had A-V conduction disturbances documented during early infancy that progressed to complete A-V block later in life. All six patients required pacemaker implantation and five of the six patients died. This report discusses the clinical presentation of complete AV block and left isomerism and reviews the literature.

Risk factors for coronary artery disease in children of affected families.

Risk factors for coronary artery disease were present to a greater degree in children of men who had experienced premature myocardial infarction when compared to children of unaffected male parents. Levels of cholesterol and body weight, as well as family history of premature CAD, differed significantly between the groups of children. The chance of identifying a child with hyperlipidemia was three times greater if the father had premature CAD. Data regarding familial aggregation of risk factors for CAD are reviewed and their significance discussed.

The fast-slow form of atrioventricular nodal reentrant tachycardia in children.

An unusual form of atrioventricular (A-V) nodal reentry is described as the underlying mechanism for incessant tachycardia in two children. During tachycardia a fast pathway was utilized for anterograde conduction and a slow pathway for retrograde conduction. This is the reverse of the usual form of A-V nodal reentrant tachycardia, in which the slow pathway is utilized for anterograde conduction and the fast pathway for retrograde conduction. One patient had a smooth ventriculoatrial (V-A) conduction curve demonstrating exclusive utilization of the slow pathway for retrograde conduction. The other had a discontinuous V-A conduction curve demonstrating failure of retrograde fast pathway conduction with resultant slow pathway conduction. In both cases the retrograde effective refractory period of the fast pathway was longer than that of the slow pathway, resulting in the establishment of this unusual reentry circuit. Both patients had a superior P axis with a P-R interval shorter than the R-P interval during tachycardia, features described in a significant number of children with incessant tachycardia. This unusual form of reentrant tachycardia can be suggested by its electrocardiographic pattern and is another mechanism for reentrant tachycardia not previously documented in children.

High-dose propranolol therapy in the management of supraventricular tachycardia

Five patients, age 3 weeks to 11 years, presented with supraventricular tachycardia that remained uncontrolled following adequate digitalization. Four of these patients underwent invasive electrophysiologic studies to determine the mechanism of the arrhythmias. Of these four patients, three had concealed Wolff-Parkinson-White syndrome, and one patient had evidence of dual A-V nodal pathways. Propranolol was added to the medical treatment and was administered orally in doses ranging from 7 to 14 mg/kg/day (average 9 mg/kg/day). All five children remain free of their tachycardia except for one patient who occasionally has supraventricular tachycardia with febrile illnesses. No adverse reactions to these high doses of propranolol were encountered.

Hemodynamics and intracardiac conduction after operative repair of tetralogy of fallot

Electrophysiologic studies were performed in 47 children aged 3 to 18 years, 15 of whom had cardiac arrhythmias 1 to 15 years after repair of tetralogy of Fallot. Six exhibited sinus or atrioventricular nodal dysfunction, 8 had ventricular extrasystoles, and 1 had supraventricular tachycardia. Hemodynamic and electrophysiologic data were obtained at postoperative catheterization. Although electrophysiologic responses were abnormal in a proportion of both the children with and those without arrhythmia, hemodynamic values were similar. Three of 6 children with impaired sinus impulse generation or atrioventricular nodal conduction had a prolonged A-H interval, and in 3 Wenckebach heart block developed at low pacing rates. Ventricular ectopic rhythm was not associated with any particular abnormality of basic intracardiac conduction intervals. Thus, arrhythmias and conduction abnormalities are not consistently related to residual right ventricular hypertension. Abnormalities in electrophysiologic function are common after repair of tetralogy of Fallot in patients with sinus rhythm and may have prognostic implications for these patients.

Infantile hypertrophic cardiomyopathy of glycogenosis type IX: isolated cardiac phosphorylase kinase deficiency.

Abstract. Glycogen storage disease confined to the heart due to cardiac phosphorylase kinase deficiency causes a fatal infantile cardiomyopathy. Cardiomegaly can be detected in utero and is progressive. Electrocardiographic and echocardiographic findings are characteristic but not specific; these include large QRS complexes, short PR interval, and a hypertrophic nonobstructive pattern. Conclusive diagnosis requires biochemical analysis of myocardium, which may not be possible premortem due to the amount of tissue required. Pathologic examination of a standard cardiac biopsy can provide a presumptive diagnosis. There is no current treatment except a heart transplant. Infants succumb to heart failure and/or respiratory compromise due to pulmonary compression. This is a rare entity; only three cases have been reported to our knowledge. We report two additional cases.

Atrial flutter and atrial fibrillation associated with Wolff-Parkinson-White syndrome in childhood

SummaryAtrial flutter, atrial fibrillation, or both, with the Wolff-Parkinson-White syndrome are reported in four children aged between 6 days and 12 years. The ECGs of all four patients revealed rapid ventricular rates and aberrant intraventricular conduction when atrioventricular (AV) conduction occurred via the accessory connection and slowing of the tachycardia with normalization of the QRS complex when AV conduction occurred via the AV node-His Purkinje system. Three had associated heart disease; one had a chronic congestive cardiomyopathy, one had Ebsteins anomaly of the tricuspid valve, while in the third patient an atrial septal defect was identified. When atrial flutter or fibrillation are combined with accessory AV connections, promotion by digoxin of very fast ventricular rates has been reported in adults but not in infants and older children. In two of our patients, one aged 6 days and one aged 6 months, digoxin may have produced this undesirable effect. Electrophysiologic studies as well as cardiac catheterization may be necessary for complete diagnostic evaluation in such cases. Quinidine should be considered in the management of these patients, and the use of digoxin alone may be contraindicated.

Atrioventricular reciprocal rhythm and chronic reciprocating tachycardia in a newborn infant with concealed Wolff-Parkinson-White syndrome.

A case of atrioventricular reciprocal rhythm and chronic reciprocating tachycardia in a newborn infant is presented. Electrophysiological studies suggest that these rhythm disturbances are related to the presence of a right-sided atrioventricular accessory pathway capable only of retrograde conduction (concealed Wolff-Parkinson-White syndrome). The technique of recording the sequence of atrial activation during the tachycardia is described and its clinical importance emphasised.

Pulsed Doppler echocardiographic detection of coronary artery to right ventricle fistula

SummaryThe pulsed Doppler echocardiographic (PDE) findings in a case of coronary artery right ventricle fistula are described. The PDE examination revealed normal flow patterns within the right atrium, pulmonary artery, and left ventricle, thus excluding these structures as the distal site of the fistula. Sampling within the right ventricular inflow revealed a turbulent, continuous, systolic-diastolic flow pattern that suggested the right ventricle was the distal end of the fistula. Postoperatively, the PDE examination of the right ventricle reverted to a normal, nonturbulent, phasic flow pattern. We conclude that PDE may be a useful noninvasive method of defining the site of drainage in cases of coronary artery fistula.