Peter S. Hesslein

Atrial flutter in the young: a collaborative study of 380 cases

As children with cardiac disease grow older, atrial flutter becomes more prevalent. A collaborative study was performed in 19 institutions to determine the clinical characteristics of these children and the factors affecting prognosis. There were 380 patients with one or more electrocardiographically documented episodes of atrial flutter that first occurred between ages 1 and 25 years (mean age at onset 10.3). Episodes of flutter continued to occur for a mean of 2.5 years after the onset. Of the 380 patients, 60% had repaired congenital heart disease, 13% palliated congenital heart disease, 8% unoperated congenital heart disease, 8% an otherwise normal heart, 6% cardiomyopathy, 4% rheumatic heart disease and 2% other lesions. Overall, drugs were effective in eliminating atrial flutter in 58% of patients; specifically, amiodarone and digoxin plus quinidine were effective in 53%, digoxin alone in 44% and propranolol in 21%. Amiodarone was effective in seven (78%) of nine patients. Corrective surgery was performed after the onset of atrial flutter in 66 patients; in 52% the atrial flutter was easier to control or it resolved and in only 4% it was worse. At follow-up (mean 6.5 years), 83% of the patients were alive (49% without atrial flutter and 34% with atrial flutter) and 17% died (10% suddenly, 6% of nonsudden cardiac cause and 1% of noncardiac cause). Cardiac death occurred in 20% of those for whom an effective drug could not be found to eliminate atrial flutter compared with 5% of those who were treated with an effective drug (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Congenital Stenosis of Individual Pulmonary Veins: Clinical Spectrum and Unsuccessful Treatment by Transvenous Balloon Dilation

Congenital stenosis of the pulmonary veins is a rare but frequently lethal congenital cardiac abnormality. Eight patients with this malformation were diagnosed, evaluated and treated. All eight patients had associated congenital cardiac defects. Two of the eight died, one of sepsis and one after operative pulmonary venoplasty. In three patients who underwent transvenous balloon catheter dilation of the stenosis the procedure provided immediate but transient relief of the stenosis. The prognosis for symptomatic infants with pulmonary vein stenosis is poor and its treatment an enigma.

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. Atrial flutter was present in 16 patients, ventricular tachycardia in 14 patients and supraventricular tachycardia in 9 patients. The most common diagnosis (14 patients) was postoperative repair of congenital heart disease. The dose ranged from 2.5 to 21.6 mg/kg per day (mean 8.2). Elimination of arrhythmia (on 24 hour electrocardiography) occurred in 15 of 16 patients with atrial flutter, 11 of 14 with ventricular tachycardia and 5 of 9 with supraventricular tachycardia. Symptomatic side effects were: rash (three patients), headache (two patients), nausea (one patient) and peripheral neuropathy (one patient); seven patients had asymptomatic corneal microdeposits which normalized in all after the drug was discontinued. No side effects occurred in patients younger than 10 years of age. The following changed with treatment (p less than 0.05): heart rate decreased (three patients with atrial flutter and sick sinus syndrome required pacemaker implantation for bradycardia) and QTc increased; thyroxine (T4) and serum reverse triiodothyronine (T3) increased. During follow-up study (range 6 months to 3 years), 21 of the 39 patients continued to take amiodarone with complete control of arrhythmias, 9 were no longer taking the drug and 9 died (7 nonsudden and 2 sudden deaths). Amiodarone is an extremely effective treatment for infants and children with tachyarrhythmias resistant to conventional treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Congenital complete atrioventricular block: Clinical and electrophysiologic predictors of need for pacemaker insertion

Because of initial Adams-Stokes attack in the patient with congenital complete atrioventricular (A-V) block may sometimes prove fatal, there is a need to be able to identify the patient at great risk of having such attacks. Twenty-four children with congenital complete A-V block were followed up for 1 to 19 years to determine the efficacy of current methods of predicting risk for Adams-Stokes syncope and the usefulness of pacemaker therapy in relieving symptoms. The heart rate at rest, configuration of surface electrocardiographic complexes, data obtained during intracardiac electrophysiologic study and response to graded treadmill exercise testing were compared in children with and without syncope. One or more Adams-Stokes episodes were experienced by eight children, one of whom died. Only a persistent heart rate at rest of 50 beats/min or less demonstrated any significant (probability [p] less than 0.01) correlation with the incidence of syncope. Intracardiac electrophysiologic study was of little benefit because of site of block did not correlate with syncope. Although the increase in heart rate during treadmill exercise testing showed no correlation with prevalence of syncope or location of block, exercise-induced ventricular ectopic beats may have predictive value in older children and young adults. Ventricular pacemakers were implanted in 10 children. Each child was asymptomatic over a 1 to 10 year follow-up period. Because extreme bradycardia may contribute to the prevalence of Adams- Stokes attacks in children with congenital complete A-V block, careful evaluation of heart rate at rest may be an effective means of differentiating patients at risk of syncope. Pacemaker therapy is a feasible and effective method of treatment in young children and relieves symptoms

Atrial automatic tachycardia in children

Abstract Atrial automatic tachycardia (AAT) is an uncommon arrhythmia that usually occurs in the young and persists for months or years. 1 Although a variety of names has been applied to it, there is general agreement as to its clinical manifestations 2,3 and presumed mechanism. 1,3 It is characterized by distinct P waves with a normal or minimally prolonged PR interval. Abnormalities in atrial rate, P-wave axis or morphology help to distinguish it from sinus tachycardia, while the observation of second-degree atrioventricular block without interruption of the atrial rhythm eliminates all forms of atrioventricular reciprocating tachycardia from consideration. The wide variability in tachycardia rate, both at its initiation and as it persists over time, has tended to support the impression that this arrhythmia is due to rapid discharges from an automatic focus in the atrium rather than involving reentry in a well-defined circuit. The inability to induce or terminate the arrhythmia by standard programmed electrical stimulation techniques lends further credence to this hypothesis. AAT is difficult to treat medically 1,3 and may cause dilated cardiomyopathy. 4 Recently, surgical ablation of the tachycardia focus has been recommended as a curative treatment for AAT and associated cardiomyopathy. 4 We report 9 welldocumented cases of ATT in children and use this experience as the basis for proposing a treatment rationale.

Successful surgical treatment of atrial, junctional, and ventricular tachycardia unassociated with accessory connections in infants and children

Five children with severe, life-threatening tachydysrhythmias were treated successfully with surgery. Three had atrial ectopic automatic tachycardia (AET), one had AV junctional (his bundle) automatic ectopic tachycardia (JET), and one had ventricular reentry tachycardia (VT). The mechanism and site of the tachycardia were diagnosed preoperatively using intracardiac electrophysiologic studies (EPS). Medical management with all available drugs failed to control the tachycardia in each patient. The two patients with left atrial AET underwent cryoablation of the focus using cardiopulmonary bypass. The patient with right atrial AET had removal of the anterior one third of the right atrial appendage and cryoablation of the edges. The patient with AV JET first had incision and suture ligation of the bundle of His and implantation of a ventricular pacemaker, but the tachycardia recurred 2 weeks later. Cryoablation of the bundle of His prevented further recurrences. Tachycardia stopped in the patient with VT during incision of a tumor in the apex of the left ventricle. No patient had tachycardia after surgery and none has required medical treatment.

Effects of verapamil on supraventricular tachycardia in children

Abstract Thirteen patients, aged 6 weeks to 16 years, with uncontrolled recurrent Supraventricular tachycardia were given intravenous verapamil in an attempt to abolish an episode of Supraventricular tachycardia. All patients had had intracardiac electrophysiologic studies to define the mechanism of their tachycardia. In seven patients conversion to sinus rhythm occurred after administration of verapamil: Five of the seven had atrioventricular (A-V) nodal reentry as the mechanism of their supraventricular tachycardia; the other two had reentrant tachycardia involving an accessory pathway. Verapamil was effective in abolishing the Supraventricular tachycardia in these patients, probably by prolonging the A-V nodal refractory period and conduction, thus breaking the reentrant circuit. In six patients there was no conversion to sinus rhythm: Four of the six had automatic atrial ectopic tachycardia and two had automatic junctional ectopic tachycardia. Among the four patients with automatic atrial ectopic tachycardia, a junctional escape rhythm developed in one, and second degree A-V block developed in the others. The two patients with junctional ectopic tachycardia had severe symptomatic arterial hypotension after verapamil and required resuscitation with intravenous calcium chloride. In spite of the good response to intravenous verapamil in the seven patients with reentrant tachycardia, only four of the seven could be maintained successfully on long-term oral therapy. The patients who experienced conversion to sinus rhythm with an intravenous bolus dose of verapamil but in whom Supraventricular tachycardia could still be induced with programmed stimulation could not be maintained successfully on oral therapy. It is concluded that verapamil is an effective antiarrhythmic agent that can (1) abolish the acute episode of Supraventricular tachycardia only in cases due to reentrant mechanisms, and (2) be used as an oral medication to prevent recurrences of supraventricular tachycardia in patients in whom the arrhythmia cannot be induced with programmed stimulation after intravenous doses of the drug.

Exercise assessment of sinoatrial node function following the Mustard operation

To screen for sinoatrial node dysfunction following the Mustard procedure for transposition of the great arteries, we studied the chronotropic response to graded maximal treadmill exercise in 29 patients at mean 6.7 years after operation. Although 93% of patients had normal resting heart rate (HR), 83% demonstrated significant depression of maximum HR and/or recovery HR after termination of exercise. These findings were similarly present among a subset of 13 patients with normal exercise tolerance. Resting and exercise-induced HR in 10 patients receiving chronic digoxin therapy were no different than in the 19 patients without medication. Sixteen patients with abnormal chronotropic responses to exercise had intracardiac electrophysiologic evaluation which confirmed sinoatrial node dysfunction in nine. Abnormal HR responses did not correlate with clinical symptoms, cardiac arrhythmias, or postoperative hemodynamics. Maximal exercise testing may be a sensitive noninvasive method to identify sinoatrial node dysfunction in postoperative children.

Prognosis of symptomatic coarctation of the aorta in infancy

Medical and surgical advances have improved the outlook for infants with symptomatic coarctation of the aorta. To help predict the clinical course of individual patients and to aid in individualizing their treatment, a 10-year experience with this condition was reviewed. Of 97 infants with symptomatic coarctation, 10 had isolated defects. In these patients, medical treatment was successful and surgical intervention could be postponed to allow for growth. The 87 other patients with associated cardiac defects were generally sicker at presentation and required earlier operation. Eleven of these died before surgical correction, 10 died at the time of repair, and 13 died later. The overall survival rate after 8 years was 62%, with most deaths occurring in the first 6 months of life. Late surgical results are flawed by a 32% rate of residual coarctation. Late postoperative hypertension is uncommon, and is usually attributable to a residual coarctation.

Ventricular tachycardia related to transcutaneous pacing.

A 3-year-old child with Haemophilus influenzae endocarditis and aortic route abscesses presented with sudden cardiovascular collapse. During resuscitation, the child was noted to be in complete heart block. Transcutaneous pacing was instituted three times, and ventricular dysrhythmias were associated with each pacing attempt. When pacing was discontinued, the patient spontaneously reverted to complete heart block without ventricular ectopy. An emergency thoracotomy revealed rupture of the aortic route, and the patient died during surgery. Transcutaneous pacing may precipitate serious dysrhythmias; appropriate precautions are recommended.