Prevention of sudden death after repair of tetralogy of Fallot: treatment of ventricular arrhythmias.

The majority of sudden deaths after repair of tetralogy of Fallot have been presumed to be due to ventricular arrhythmia; however, it remains to be demonstrated that antiarrhythmic medication reduces the incidence of sudden death. Since 1978, ventricular arrhythmias have been treated aggressively; these include any ventricular arrhythmia on routine electrocardiogram and more than 10 uniform premature ventricular complexes per hour on 24 hour electrocardiogram. A review was undertaken of 488 patients followed up for more than 1 month after repair of tetralogy of Fallot (mean follow-up time 6.

Long-term follow-up of dysrhythmias following the Mustard procedure.

Earlier reports have suggested that the incidence of dysrhythmias after the Mustard procedure can be reduced if the sinoatrial node (SAN) is protected during surgery. To determine if these initial differences continue after longer follow-up, we examined all ECGs available for three groups of patients operated upon from January, 1965, through December, 1977. Group A included 37 patients who survived the operation prior to January, 1972, when surgical modifications were initiated to protect the SAN; group B included 44 patients available for follow-up who were operated upon from 1972 through 1974; and group C consisted of the 39 patients available for follow-up operated upon from 1975 to 1977.

Supraventricular arrhythmias in children.

Sudden death may occur in children with supraventricular arrhythmias. Sick sinus syndrome, particularly if associated with tachycardia, may result in sudden death in children who have had open heart surgery and rarely in children with a normal heart. Children with supraventricular tachycardia rarely die.

Exercise testing in children with Wolff-Parkinson-White syndrome.

Exercise testing using a modified Bruce treadmill protocol was performed by 17 children with Wolff-Parkinson-White (WPW) syndrome. All had intracardiac electrophysiology studies as well. Endurance time, heart rate and blood pressure were normal during exercise.

Transvenous catheter ablation of a right atrial automatic ectopic tachycardia.

A 10 year old patient with right atrial automatic ectopic tachycardia underwent successful transvenous catheter ablation after endocardial mapping. Tachycardia had been present for 7 years before ablation and associated with development of dilated cardiomyopathy. A single 50 J discharge at the point of earliest atrial activation was followed by the establishment of sinus rhythm that remains at 10 months' follow-up.

The leftward deletion alpha-thal-2 haplotype in a black subject with hemoglobin SS.

We have identified a black individual with homozygous sickle cell anemia who is the silent carrier of alpha-thalassemia (genotype - alpha/alpha alpha) due to heterozygosity for the leftward deletion alpha-thal-2 haplotype. This deletion has not been described previously in a black subject and is the only leftward deletion that we have found among 255 alpha-thal-2 chromosomes from sickle cell subjects. Its effects on the clinical, hematologic, biosynthetic, and cellular pathology of sickle cell anemia resemble those reported for the common alpha-thalassemia genotypes of the black population.

Chronic supraventricular tachycardia. A curable cause of congestive cardiomyopathy.

Two cases of congestive cardiomyopathy were proved to be due to chronic atrial automatic-focus tachycardia. Surgical elimination of the tachycardia resulted in normalization of cardiac function in both cases. We suggest that patients with congestive cardiomyopathy be carefully screened for supraventricular tachycardia.

Wolff-Parkinson-White syndrome and supraventricular tachycardia during infancy: management and follow-up.

The records of 90 patients with Wolff-Parkinson-White syndrome who presented with supraventricular tachycardia in the first 4 months of life were reviewed. Among these, 63% were male. Structural heart disease was present in 20%, most commonly Ebstein's anomaly.

Surgical management of refractory supraventricular tachycardia in infants and children.

Sixty-seven children underwent attempted surgical correction of refractory supraventricular arrhythmias using a combination of intraoperative electrophysiologic mapping followed by surgical division or cryoablation of an aberrant conduction pathway or atrial ectopic focus. The patients ranged in age from 4 months to 18 years (mean 11.4 years).

Use of atrial pacing in a young population.

Forty pediatric and young adult patients (1-20 years; mean, 11 years of age) had implantation of atrial demand (AAI) pacemakers over a 5.5 year period. Nineteen were implanted by epicardial technique and 21 transvenously.

Critical analysis of sensors for physiological responsive pacing.

Physiological responsive pacing includes the application of sensors to measure physiologic variables, which in turn are used to control pacemaker rate. Six such systems are evaluated based on a comparison of (1) speed of response, (2) sensor reliability, and (3) system specificity. Although there is not a clear-cut solution, and every system has some weaknesses, several sensors seem more feasible than others.

Amiodarone treatment of critical arrhythmias in children and young adults.

The majority of sudden cardiac deaths in children occur in patients with prior arrhythmias and an abnormal heart. Amiodarone was given to 39 young patients (35 with an abnormal heart) with arrhythmias unresponsive to conventional treatment. Their age ranged from 6 weeks to 30 years with nine patients younger than 2 years of age.

A family history of seizures associated with sudden cardiac deaths.

Hereditary prolongation of the Q-T interval is associated with ventricular dysrhythmias. Children with hereditary prolongation of the Q-T interval may have symptoms that seem related to a neurologic abnormality. Two families had members who had been treated with phenytoin sodium for seizures and had died suddenly when the medication was discontinued.

Epicardial cryoablation of the bundle of His. An experimental study.

An extracardiac, transepicardial approach to the atrioventricular junction, allowing selective cryoablation of the bundle of His, was performed in 10 mongrel dogs. This technique appears to minimize dissection complications, the risk of endocardial damage, and injury to the tricuspid valve, which are reported with endocardial cryoablation. All dogs survived this experiment, and no morbidity was reported.

The incidence of retrograde conduction in children.

With the increasing use of "physiological" pacemakers in the pediatric age group, retrograde conduction in children has become of clinical importance. Pacemakers which sense atrial depolarization may sense "retrograde" P waves. The pacemaker may then act as the antegrade limb of a reciprocating tachycardia circuit, while the patient's own conduction system acts as the retrograde limb.

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.