Safety and Efficacy of Radiofrequency Catheter Ablation for Tachyarrhythmia in Children Weighing Less Than 10 kg.

An increasing number of children are undergoing radiofrequency catheter ablation (RFCA) for tachyarrhythmia. However, infants and toddlers undergoing RFCA are often resistant to medication or need to eliminate arrhythmia substrate, and the risks of RFCA complications are still high in infants and toddlers. From April 2008 and December 2016, 285 children who underwent radiofrequency catheter ablation (RFCA) were stratified according to body weight (group A, less than 10 kg, n = 22; group B, over 10 kg, n = 263) and the clinical features of RFCA were retrospectively reviewed in these groups. Indications for RFCA included drug-refractory tachyarrhythmia or symptomatic tachycardia and tachycardia-induced cardiomyopathy. The acute success rate in this group was 90.9%, with a relatively low recurrence rate (15.0%) after 7.0 ± 1.6 years follow-up. We performed RFCA using only 2-4 catheters in all cases. Major complications included complete right bundle branch block in one patient. No significant differences in rates of success, recurrence, or complications were noted between children weighing less and more than 10 kg. RFCA is safe and efficacious for tachyarrhythmia even in patients weighing less than 10 kg.

Electrophysiologic studies and radiofrequency catheter ablation of ectopic atrial tachycardia in children.

Ectopic atrial tachycardia (EAT) often resists medical therapy, making radiofrequency catheter ablation (RFCA) the preferred treatment. This study reviewed the records of 35 patients who underwent electrophysiologic studies (EPS) and 39 RFCA procedures for EAT during a 10-year period. Of the 35 patients, 10 (28%) presented with decreased ventricular function and tachycardia-induced cardiomyopathy (TIC). The EAT originated on the right atrial side in 19 patients (54%) and on the left atrial side in the remaining 16 patients (46%). The right atrial sites included the right atrial appendage (RAA) (n = 9, 25%), the tricuspid annulus (n = 7, 20%), and the crista terminalis (n = 3). The left atrial sites included the left atrial appendage (LAA) (n = 6, 17%), the pulmonary veins (n = 5, 14%), the mitral annulus (n = 3), and the posterior wall of the left atrium (n = 2). The mechanism of all EAT probably is automaticity. All EATs could be abolished using RFCA. Follow-up data were available for all patients 2 to 8 years after RFCA. All 35 patients remained recurrence free, and ventricular function improved for all 10 patients with TIC. The origin of EAT in children differed from its origin in adults. The authors conclude that RFCA is a safe and effective treatment option for children with refractory EAT and should be considered early in the course of their illness.

Catheter ablation for a right anteroseptal accessory pathway in a patient with an endocardial cushion defect.

We report a radiofrequency catheter ablation for atrioventricular reentrant tachycardia in a patient with a right anteroseptal accessory pathway complicating an endocardial cushion defect. His bundle potential was recorded 20 mm posterior to the accessory pathway. In the presence of associated congenital heart disease, it is very important to understand the anatomy of the conduction system prior to radiofrequency catheter ablation.

Partial left ventriculectomy in association with dilated cardiomyopathy: echocardiographic follow-up.

Left ventricular function after a left ventriculectomy was assessed in a patient with idiopathic dilated cardiomyopathy (DCM) who has survived longer than any other patient in Japan after this operation. The 19-year-old male had a history of cerebral infarction because of left ventricular thrombus associated with DCM. In order to remove the thrombus and improve left ventricular function, an approximately 12x4cm piece of myocardial tissue was resected according to the methods of Batista's operation. Left ventricular diastolic dimension was temporarily reduced 1 month after surgery, but increased again. During the 45 months of follow-up, left ventricular diastolic dimension, cardiac output and New York Heart Association functional class remain unchanged from the preoperative values.

Right-to-Left Shunt Through a Ventricular Septal Defect During Sedated Sleep.

A 10-month-old infant with Down's syndrome developed cyanosis due to a right-to-left shunt through a ventricular septal defect during sedated sleep induced for echocardiography. During cardiac catheterization, arterial oxygen saturation decreased, and arterial carbon dioxide concentration increased. Various echocardiographic parameters during sedated and natural sleep were compared. It was considered that hypoventilation caused by the narrowed upper airway was induced by sedated sleep. We conclude that the influence of sedatives should be considered in the estimation of echocardiographic data if an infant with Down's syndrome has a ventricular septal defect with pulmonary hypertension.