A total of 114 children (age range 4 months to 18 years) underwent definitive operation for life-threatening or incessant tachydysrhythmias resulting from accessory conduction pathways (
Kent bundle) (79), atrial ectopic foci (18), or ventricular ectopic foci (17). Of the patients with the accessory pathway type of
supraventricular tachycardia, 63.3% (50/79) had classical
Wolff-Parkinson-White syndrome whereas 36.7% (29/79) had retrograde conduction only across the pathway. Locations of the pathways were as follows: left posterior 48.1% (38/79), right anterior or lateral 27.8% (22/79), posterior septal 16.5% (13/79), anterior septal 3.8% (3/79), and both right and left 3.8% (3/79). With increasing experience, the success rate (cure of
tachycardia) improved from 85% in the first 40 patients to 95% in the last 40 patients. One surgical death (1.3%) occurred secondary to a paradoxical air
embolus.
Atrial ectopic tachycardia was treated by
cryoablation (nine), excision (one), combined excision and
cryoablation (six), and atrial disconnection (two). The ectopic focus was located on the right atrial wall in 13 patients (72.2%) and
cardiopulmonary bypass was required in eight (44.4%). The operation was successful in 89%; two patients with multiple ectopic foci continued to have uncontrolled
tachycardia after the operation.
Ventricular tachycardia presenting in the first 2 years of life was due to gross
tumor in three cases (
rhabdomyoma two,
fibroma one) or microscopic hamartomatous change (Purkinje
tumor) in five cases and was treated by excision alone or with adjuvant
cryoablation. In four cases no
tumor was found but the area of ectopic focus was successfully cryoablated. One child with diffuse endocardial
tumor died of
low cardiac output after the operation.
Ventricular tachycardia in older children was localized to outflow patch
aneurysms or other areas in the right ventricle following
tetralogy of Fallot repair (three patients, treated by excision or
cryoablation) and
arrhythmogenic right ventricular dysplasia (two patients, treated by right ventricular disconnection). We conclude that mapping and operation for
supraventricular tachycardia resulting from accessory pathways are predictable and curative in a high percentage of patients.
Atrial ectopic tachycardias are more difficult to precisely localize but can be cured by a combination of excisional and cryoablative techniques.
Ventricular tachycardia in infants is lethal and is commonly due to ectopic foci or microscopic
tumors that may not be apparent on preoperative angiography or echocardiography. Electrophysiologically directed operations in these patients can be lifesaving.