Tetralogy of Fallot: postoperative electrophysiologic studies

The clinical profile and surgical treatment of tetralogy of Fallot in the adult: results of repair in 200 patients

This report describes our 17-year experience with intracardiac repair in 200 patients older than 14 years with tetralogy of Fallot. Congestive failure, hemoptysis, and cerebral abscess were present in 15, 10, and 3% of patients, respectively. Prior palliative shunts had been performed in 24.5% only. Polycythemia with a hematocrit greater than 60% was noted in 100 patients but was not considered an incremental risk factor (p greater than 0.05). A transannular gusset was utilized in 74% of patients in the last 5 years of the study. Hospital mortality was 1.3% in the last 5 years. Ninety-seven percent of survivors at follow-up are asymptomatic and leading an active life. Recatheterization data from 86 patients revealed excellent or good results in 88%. The incidence of residual ventricular defect was 1% overall, with a zero incidence in the last 12 years. On the basis of this review, we consider that easier and hemodynamically satisfactory repair has been achieved in the adolescent and older patient compared with the child. The ultimate longevity, however, must await the results of long-term functional and serial hemodynamic evaluation.

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.

Electrophysiologic residua and sequelae of surgery for congenital heart defects

Postoperative arrhythmias may occur in any patient who undergoes intracardiac surgery for a congenital heart defect. The correction of certain intracardiac heart defects predisposes to a large incidence of cardiac arrhythmias. Ventricular arrhythmias and conduction disturbances are seen after correction of tetralogy of Fallot, ventricular septal defect and atrioventricular canal defect. Supraventricular arrhythmias and sinus nodal dysfunction may be seen after surgery for transposition of the great arteries or atrial septal defect. The identification, evaluation and treatment of these patients are discussed.

Long-term evaluation (12 to 22 years) of open heart surgery for tetralogy of Fallot

Four hundred seventy-five patients underwent repair of tetralogy of Fallot from 1955 to 1964; 396 of these were hospital survivors and were followed up for 12 to 22 years. An excellent late clinical result was maintained by 87 percent of the 396 hospital survivors. A less than excellent result in the remaining 13 percent of hospital survivors was caused by late mortality in 7 percent (sudden death in 3 percent, death due to cardiac causes in 2 percnt and death due to noncardiac causes in 2 percent), required reoperation in 4 percent (mainly because of residual ventricular septal defect) and development of symptoms in 2 percent. Postoperative cardiomegaly (cardiothoracic ratio greater than 0.55) was observed in 60 (25 percent) of 246 patients who had a follow-up chest roentgenogram, and was more common among those who died late or remained symptomatic. Among the few patients with inadequate surgical relief of right ventricular hypertension who did not have transanular patch repair, the hypertension did not tend to decrease progressively, whereas it did decrease in patients who had patch repair. No late sudden deaths were encountered in 20 patients shown to have postoperative right bundle branch block plus left axis deviation (bifascicular block pattern). Pulmonary valve incompetence appeared to have relatively little harmful influence on the late result, causng cardiac disability in 1 percent of the patients and appeared to be the main contributing factor of postoperative cardiomegaly in 13 (5 percent) of the 246 patients who had a follow-up chest roentgenogram. Most late deaths and complicatins appeared within 2 years of operation, and accelerating deterioration in late results did not occur as the follow-up extended beyond 2 decades.

Sudden death after repair of tetralogy of Fallot. Electrocardiographic and electrophysiologic abnormalities

In order to try to determine the mechanism of sudded death in patients after surgical repair of tetralogy of Fallot, electrocardiographic, intracardiac electrophysiologic, and clinical data of 51 children who had postoperative intracardiac electrophysiologic studies were reviewed. Ninety-four percent had developed right bundle branch block (RBBB) and 16 percent had additional left anterior hemiblock (LAH). Two had had transient complete A-V block (CAVB) and one had permanent CAVB. Six had a first degree A-V block and nine had premature ventricular contractions (PVC). Nine patients were found to have prolonged intra-atrial conduction times, four prolonged A-V nodal conduction, four prolonged His-Purkinje conduction, and five prolonged corrected sinus node recovery times. Patients with first degree A-V block or LAH did not have an increased incidence of abnormalities on electrophysiologic study. No patient with RBBB and LAH developed complete A-V block or died. Three of the nine patients with PVCs died, one of intractable ventricular fibrillation and two suddenly, presumably of dysrhythmia. All three had significant congestive heart failure. Although late complete A-V block occurs and should be watched for, ventricular dysrhythmias in patients with PVCs may be the cause of most sudden deaths after tetralogy repair. We currently are treating all of our postoperative tetralogy patients who have PVCs with quinidine or propranolol.