Ventricular arrhythmias and sudden death in children.

In children, sudden death related to ventricular arrhythmias occurs virtually always in a patient with an abnormal heart. Therefore, children with ventricular tachycardia should be thoroughly investigated by anatomic cardiac catheterization and possibly electrophysiologic study. Sudden death may occur in a patient who had been relatively asymptomatic. This especially occurs in patients after repair of congenital heart disease. The patient may also never have had documented ventricular tachycardia, although most have had at least premature ventricular complexes on a Holter monitor recording. Finally, sudden death related to ventricular arrhythmias can often be prevented with vigorous medical and surgical therapy.

Flecainide for supraventricular tachycardia in children.

The clinical efficacy, adverse effects and pharmacokinetics of flecainide were evaluated in 16 pediatric and young adult patients with supraventricular tachycardia (SVT). Patients had received an average of 2.8 drugs before flecainide was tried. The following mechanisms of supraventricular arrhythmias were determined in patients by intracardiac electrophysiologic studies: atrioventricular node reentry, 4; reentry through an accessory connection, 7; atrial automatic focus, 2; atrial flutter, 3. Twelve patients had normal cardiac anatomy and 4 had congenital heart disease. Each patient received 2.8 mg/kg/day of flecainide divided into 2 doses 12 hours apart. After 3 days, the dose was increased to 5.6 mg/kg/day if necessary. In 14 patients, serum flecainide concentrations measured 3 to 4 days after beginning therapy ranged from 0.1 to 0.8 micrograms/ml (mean 0.40). Flecainide successfully controlled SVT in 8 of 16 patients. SVT in 3 of 7 patients with accessory connections and in 3 of 4 patients with atrioventricular node reentry was successfully controlled. In 1 of 2 patients with atrial automatic tachycardia, SVT had been completely controlled over 16 months. Only 1 of 3 patients treated for atrial flutter responded. Follow-up for successfully treated patients ranged from 4 to 16 months (median 9). Seven patients continue to take flecainide. None of the patients had clinical congestive heart failure. No drug-related adverse effects were noted on the resting surface electrocardiogram. Flecainide rarely produced proarrhythmic effects in this series. The 2 that were observed were mild and caused no clinical problems. Noncardiovascular side effects also occurred infrequently.(ABSTRACT TRUNCATED AT 250 WORDS)

Management strategies for surgical treatment of dysrhythmias in infants and children.

To elucidate the role of surgery in the management of refractory pediatric dysrhythmias, the investigators' 1987 experience with this therapy was reviewed. Sixteen patients (8 male, 8 female) had surgery. Age ranged from 3 months to 21 years (mean 7.7 years) with 2 being younger than 1 year of age. Eight patients had Wolff-Parkinson-White syndrome with supraventricular tachycardia (SVT), 6 had SVT alone and 2 had ventricular tachycardia. Patient symptoms fell into 3 distinct categories. Nine patients had frequent non-life-threatening tachycardia episodes despite aggressive medical management, 4 patients had life-threatening symptoms either related to frequent tachycardia episodes or due to side effects of drugs and 3 patients had minimal tachycardia symptoms but were judged to be at risk for sudden death. The mechanisms of the tachycardias included reentrant SVT using an accessory atrioventricular connection in 9, the permanent form of junctional reciprocating tachycardia in 2, atrioventricular node reentrant SVT in 2, atrial ectopic focus in 1 and ventricular ectopic foci in 2. Ablation techniques involved either surgical dissection or cryoablation of the arrhythmogenic substrates. There was no surgical mortality and follow-up shows 15 of 16 patients to have had no recurrence of symptomatic tachycardia without any therapy. Based on this experience, management strategies for surgical control of recalcitrant pediatric dysrhythmias are proposed. Surgery for infant dysrhythmias should be performed only for life-threatening symptoms. Beyond the first year of life, after failing 2 medications, surgical options for SVT should be considered. For patients with ventricular tachycardia, aggressive medical management with class II, IC and III agents should be attempted before surgical therapy.

Mapping and radiofrequency ablation of intraatrial reentrant tachycardia after the Senning or Mustard procedure for transposition ofthe great arteries.

The Senning and Mustard procedures are often associated with the development of atrial tachyarrhythmias, which may be a cause of sudden death. We hypothesized that atrial surgery creates barriers to impulse propagation, establishing potential routes for atrial reentry, and that mapping combined with knowledge of the surgical anatomy could identify zones that are critical to the tachycardia to be targeted for radiofrequency catheter ablation. Patients underwent mapping to identify early sites of atrial activation that were related to anatomic or surgically created obstacles, with confirmation by pacing to demonstrate concealed entrainment. Radiofrequency lesions were placed to connect these obstacles, while observing for tachycardia termination. Thirteen tachycardias were attempted in 10 patients, 10 successfully. Three patients had 2 distinct tachycardias. Successful sites were in right atrial tissue, although in many, a retrograde approach to the pulmonary venous atrium was necessary. Ablation of the clinically documented tachycardia was successful in 9 of 10 patients. The most common successful site was the region of the coronary sinus mouth, approached antegrade or retrograde. Ablation of intraatrial reentrant tachycardias after the Senning or Mustard procedure is feasible using concealed entrainment mapping techniques, but requires a detailed knowledge of the individual surgical anatomy and the ability to approach the pulmonary venous atrium. Radiofrequency ablation offers significant advantages over other management modalities in this patient group.

Late results of valvoplasty for mitral regurgitation due to rupture of chordae of the posterior (mural) cusp.

Nine patients with rupture of chordae tendinea of the posterior cusp of the mitral valve are presented. All have been treated by plication of the posterior cusp and atrial wall. The presenting postoperative features have been described: 89 per cent are markedly improved; two patients have normal heart sounds with no murmurs; 6 patients have only a Grade 1 pansystolic apical murmur. The advantages of this procedure compared with mitral valve replacement for the same condition have been presented.

The Blalock-Taussig shunt in infants: standard versus modified.

In recent years, the modified Blalock-Taussig shunt--a polytetrafluoroethylene graft from the subclavian artery to the pulmonary artery--has been preferred over the standard shunt by some surgeons because (1) it requires less dissection and (2) length of native vessels is not critical. From January, 1979, to June, 1985, we operated on 51 infants less than 1 year of age, including 26 less than 1 week of age, to palliate severe complex cyanotic congenital cardiac malformations. Twenty-four modified Blalock-Taussig shunts and 29 standard Blalock-Taussig shunts were created. The groups were concurrent. We reviewed all available cineangiograms and measured branch pulmonary and subclavian arteries. Pulmonary artery index was not different preoperatively in patients given a modified versus a standard Blalock-Taussig shunt (144 +/- 118 and 118 +/- 59 mm2/m2, respectively), but it was greater postoperatively in patients with a modified shunt (431 +/- 188 and 189 +/- 106 mm2/m2) (p = 0.07). Distortion of the pulmonary artery occurred less often after a modified Blalock-Taussig shunt (4/11) than a standard Blalock-Taussig shunt (6/8) (p = 0.06), though none of the distortions was severe. Early and late shunt failure occurred less often with a modified shunt (5/24) than with a standard shunt (15/29) (p less than 0.05). The modified Blalock-Taussig shunt had advantages over the standard Blalock-Taussig shunt in our series: pulmonary artery growth was greater, distortion of pulmonary arteries was less commonly seen, and shunt failure occurred less often. Thus, in infants, we believe the modified Blalock-Taussig shunt should be considered a reasonable alternative to the standard Blalock-Taussig shunt.

Congenital complete atrioventricular block.

The various etiologies, pathologic findings, clinical concerns, and features of congenital complete atrioventricular block are presented and discussed. In addition, prenatal and antenatal diagnostic techniques are explained and analyzed. Lastly, treatment and the issues involved in deciding proper treatment are discussed in such a way that the general pediatrician can help the family to understand and handle the problem.

Neonatal cardiac arrhythmias and their potential role in sudden infant death syndrome.

A broad spectrum of dysrhythmias effects neonates. With modern monitoring techniques, we are detecting more of them. Modern treatment techniques should allow virtually all infants to be treated successfully and to lead normal lives.