Dolores Tamer

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.

Rapidly progressive obstructive cardiomyopathy in infants with Noonan's syndrome. Report of two cases.

Two patients with hypertrophic obstructive cardiomyopathy and Noonans syndrome are presented. Both patients were found at postmortem examination to have gross malformation of the mitral valve and obliteration of the left ventricle due to muscle hypertrophy. Each case demonstrated similar clinical, echocardiographic, and angiographic findings. The poor response to medical and surgical therapy are noted.

Analysis of surgically-induced right bundle branch block pattern using intracardiac recording techniques.

SUMMARY Using intracardiac recording techniques, His bundle (H) and right ventricular apical (RVA) electrograms were recorded in 16 patients with a postoperative electrocardiographic pattern of right bundle branch block (RBBB). Their ages ranged from 5 to 12 years (mean 6.9 years) at surgery and the follow-up period was 1 to 7 years (mean 2.7 years). All were asymptomatic and in sinus rhythm at the time of study. The P-A interval was normal in all and the A-H, H-V, and V-RVA intervals were prolonged in one, one, and six patients, respectively. The V-RVA interval was normal (≤30 msec) in ten out of the 1I patients (91%) without associated left anterior hemiblock (LAH), indicating a physiologically intact main right bundle branch, and was abnormally lengthened (45–62 msec) in all five patients (100%) with associated LAH. These findings suggest that there are two subgroups of patients with surgically-induced RBBB pattern and the measurement of the V-RVA interval in conjunction with the H-V interval may be of ultimate importance in understanding the longterm prognostic implication of surgically-induced RBBB pattern with or without LAH.

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.

Two-dimensional echographic observations in major detachment of a prosthetic aortic valve

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Premature ventricular contractions as the presenting feature of mitral valve prolapse in childhood

REFERENCES 1. Furman S, Parker B, and Escher DJW: Transtelphone pacemaker clinic, J Thor Cardiovasc Surg 61:827, 1971. 2. Furman S, and Escher DJW: Transtelephonic pacemaker monitoring: Five years later, Ann Thorac Surg 20:326, 1975. 3. Starr A, Dobbs J, Dabolt L, and Pierie W: Ventricular tracing pacemaker and teletransmitter follow-up system, Am J Card 32:956, 1973. 4. Hasin Y, David D, and Rogel S: Diagnostic and therapeutic assessment by telephone electrocardiographic monitoring of ambulatory patients, Br Med J 2:609, 1976. 5. Scheidt S, McCAll J, Wilner G, and Killip T: Remote electrocardiography clinical experience with telephone transmission of electrocardiograms, JAMA 230:1293, 1974. 6. Williams RL: Use of transtelephonic electrocardiography in patients with symptoms suggesting cardiac arrhythmias, Pediatrics 61:493, 1978. 7. Crippled Childrens Representative Manual, Bureau of Personal Health Services, Regional Offices, Michigan Department of Public Health, Appendix, Exhibit 2, 1976, p 4.

Electrocardiographic changes following surgical treatment of congenital cardiac malformations

I MPROVEMENTS in surgical techniques in the past 20 yr have brought a significant decrease in operative mortality and the survival of many more patients with congenital cardiac malformations into adulthood) Various electrocardiographic (ECG) patterns evolve postoperatively in these patients. Cardiac surgery per se or the natural postoperative history of the defect may be responsible for these ECG changes. Regardless of the cause of these changes, the evaluation of the postoperative ECG is important in the clinical assessment of these patients. Many of these ECG changes are easily understood, but in some, controversies exist as to their etiology and their relationship to prognosis. Because of these controversies we will review the late and persistent postoperative ECG findings in congenital cardiac lesions, with particular reference to: (1) resolution of abnormal preoperative findings, (2) the development of new abnormal postoperative patterns, and (3) chronic rhythm disturbances. The following isolated congenital cardiac malformations will be considered: valvar aortic .stenosis, valvar pulmonic stenosis, simple coarctation of the aorta, complete transposition of the great arteries, atrial septal defects (primum and secundum), patent ductus arteriosus, ventricular septal defects, and tetralogy of Fallot.

The Ductus Debate: Ligation in Prematurity?

This report describes 20 premature infants who have undergone surgical ligation of a patent ductus arteriosus (PDA), diagnosed solely by physical examination in all but 2 instances. There were no operative deaths. Eleven of these 20 infants had severe associated hyaline membrane disease (HMD) necessitating mechanical ventilatory support from the first or second day of life. Only 3 of these 11 infants (27%) ultimately survived to leave the hospital. In contrast, 8 of 9 premature meonates (89%) with severe congestive heart failure but without HMD were discharged alive. Surgical ligation of the PDA in a premature infant is an appropriate and successful mode of treatment when congestive heart failure is refractory to medical management. Proof is lacking, however, to establish the efficacy of PDA ligation in the premature infant with HMD.