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.

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.

We present two patients with thromboembolic pulmonary hypertension associated with unusual complications probably caused by disseminated fibromuscular dysplasia (FMD) or FMD-like vascular lesions. Intimal fibroplasia, which is typical of the vascular lesions associated with FMD, was observed in both patients. The presence of such intimal lesions suggests that there was a systemic factor that caused the formation of recurrent thrombi in the systemic vessels in these patients. These cases are the first ones reported in which an association between FMD and pulmonary hypertension has been observed. The pathogenesis of the thrombi in our patients was thought to be recurrent pulmonary thromboembolisms resulting from FMD.

ecause of its refractoriness to medical therapy and the high mortality rate, 1,2 junctional ectopic tachycardia (JET) has been treated by ablation of the atrioventricular (AV) junction using either direct 1 or radiofrequency (RF) current. 3,4 However, these therapies may result in the need for permanent cardiac pacing. Recently, selective ablation of the JET focus while preserving normal AV conduction was reported, [5][6][7][8][9] suggesting that the junctional focus is usually perinodal and that ablative lesions created over the anterior, mid or posterior septum, avoiding the His bundle, may be effective. However, in the present patient we believed that the automatic focus of the JET existed at a site ajacent to the His bundle. Case ReportThe patient was a 5-year-old boy with a tachyarrhythmia that had been present since birth and had been well controlled with propranolol and digoxin. For the 6 months prior to admission, he had recurrent episodes of tachycardia accompanied by signs of congestive heart failure, including vomiting, appetite loss, and cyanosis. Pharmacologic management with multiple antiarrhythmic drugs (excluding amiodarone) failed, and the patient was referred for catheter ablation. The 24-h Holter monitoring showed an incessant irregular narrow QRS tachycardia with a rate of 180 beats/min. Echocardiography showed a reduced left ventricular shortening fraction (22%).Two 5Fr quadripolar electrode catheters were introduced via the left femoral vein into the high right atrium and the right ventricle. A steerable 7Fr 20-pole catheter with a 2-mm interelectrode distance was placed across the tricuspid valve to record the AV junctional electrograms via a left femoral transvenous approach. A 6Fr 8-pole catheter was inserted from the right internal jugular vein into the coronary sinus. A baseline electrophysiologic study confirmed the diagnosis of JET based on the following observations: (1) during tachycardia, ventriculoatrial (VA) dissociation was present with a His potential always preceding the ventricular depolarization at an His-ventricular (HV) interval of 36 ms, (2) the earlier His potential recording was obtained by the more proximal electrode of the 20-pole catheter in the region expected to produce a His electrogram, (3) sinus beats that occasionally captured the ventricle caused a sudden shortening of the HH interval with subtle aberrancy in the QRS configuration, but the HV intervals were the same as those during tachycardia, (4) there was no evidence of retrograde atrial activation in the His bundle or the coronary sinus during tachycardia, (5) atrial overdrive pacing during tachycardia caused temporary suppression of the tachycardia, confirming normal AV nodal conduction, (6) with the termination of atrial overdrive pacing, the tachycardia immediately resumed with a warming-up of the HH interval and subtle changes in the QRS configuration (Fig 1), and (7) the tachycardia could not be terminated with either atrial or ventricular programmed pacing. A 7Fr ablation catheter (Medtronic CardioR...

A 13-year-old boy had recurrent ventricular tachycardia following surgical correction of tetralogy of Fallot. Pharmacological management with multiple antiarrhythmic drugs failed, and the patient underwent electrophysiological evaluation. A reentrant tachycardia involving a slowly conducting region in the left ventricular outflow tract was demonstrated. We performed radiofrequency catheter ablation after identifying the essential components of the reentrant circuit. The ventricular tachycardia could no longer be induced and did not recur spontaneously during a 13-month follow-up.

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.

Biochemical and radiographic abnormalities linked with phosphorus deficiency syndrome (PDS) developed in two very low birthweight (VLBW) infants fed exclusively with human milk. By increasing phosphorus (P) and calcium (Ca) intakes with the introduction of a specialized premature formula, osteopenia or rickets, as well as hypophosphatemia, hypo‐phosphaturia and increased serum alkaline phosphatase levels improved in both patients. We speculated that all VLBW infants who are being fed exclusively with human milk should be monitored for PDS and that if PDS develops, supplementation of human milk with both P and Ca appears to be necessary for its treatment.

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.