Catheter ablation in ASymptomatic PEDiatric patients with ventricular preexcitation: results from the multicenter "CASPED" study.

BACKGROUND: As there are limited data about the clinical practice of catheter ablation in asymptomatic children and adolescents with ventricular preexcitation on ECG, we performed the multicenter "CASPED" (Catheter ablation in ASymptomatic PEDiatric patients with Ventricular Preexcitation) study. METHODS AND RESULTS: In 182 consecutive children and adolescents aged between 8 and 18 years (mean age 12.9 ± 2.6 years; 65% male) with asymptomatic ventricular preexcitation, a total of 196 accessory pathways (APs) were targeted. APs were right sided (62%) or left sided (38%). The most common right-sided AP location was the posteroseptal region (38%). Ablation was performed using radiofrequency (RF) energy (93%), cryoablation (4%) or both (3%). Mean procedure time was 137.6 ± 62.0 min with a mean fluoroscopy time of 15.6 ± 13.8 min. A 3D mapping or catheter localization system was used in 32% of patients. Catheter ablation was acutely successful in 166/182 patients (91.2%). Mortality was 0% and there were no major periprocedural complications. AP recurrence was observed in 14/166 patients (8.4%) during a mean follow-up time of 19.7 ± 8.5 months. A second ablation attempt was performed in 20 patients and was successful in 16/20 patients (80%). Overall, long-term success rate was 92.3%. CONCLUSION: In this retrospective multicenter study, the outcome of catheter ablation for asymptomatic preexcitation in children and adolescents irrespective of antegrade AP conduction properties is summarized. The complication rate was low and success rate was high, the latter mainly depending on pathway location. The promising results of the study may have future impact on the ongoing risk-benefit discussion regarding catheter ablation in the setting of asymptomatic preexcitation in children and adolescents.

Implantation of an "extracardiac" internal cardioverter defibrillator in a 6-month-old infant.

In infants and small children, ICD implantation is a challenge due to technical limitations and a significant number of complications. This report describes ICD implantation in a 6-month-old infant (body weight 5.5 kg). A completely extracardiac defibrillation system was implanted using a transvenous lead subcutaneously in the back below the left scapula as the defibrillation electrode and an active-can device in the right upper abdomen. Defibrillation threshold of implantation was < or =10 J. During the follow-up of 3 months, 8 adequate ICD discharges were noted. The technique described seems feasible to facilitate ICD implantation in small infants.

[Arrhythmogenic right ventricular dysplasia/cardiomyopathy - diagnosis in childhood]. / Arrhythmogene rechtsventrikuläre Dysplasie/Cardiomyopathie. Diagnostik im Kindesalter.

Arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) is a rare, but important cause for sudden death in adolescents and young adults. Part of the patients affected show the pattern of autosomal-dominant inheritance. Two pediatric patients with ARVD/C are presented who may reflect the spectrum of clinical presentation of ARVD/C in childhood resulting in difficulties or even delay to establish the correct diagnosis. One patient with a sporadic form of ARVD/C presented with a syncope and spontaneous as well as inducible ventricular tachycardia. On the ECG, an epsilon wave could be identified. An automatic cardioverter defibrillator was implanted. The second patient had a familiar form of ARVD/C with no symptoms. There was a history of frequent sudden deaths in this family. Biopsies of the right ventricular myocardium showed fibrosis with deposition of fatty tissue. There was clear evidence of ARVD/C in the necropsy of the patient's aunt. Therapy with propanolol was started in this patient.

[Systemic lupus erythematosus-associated endocarditis in a 7-years-old girl]. / Lupus erythematodes-assoziierte Endokarditis bei einem 7 Jahre alten Mädchen.

Systemic Lupus erythematosus (SLE) is a chronic inflammatory disease, caused by a fault of the immune regulation. The etiology of the SLE is still unknown, a possible virus infection is discussed. Libman Sacks endokarditis is the most important cardiac manifestation of this illness. Diagnosis, therapy and clinical course of a 7 years old so far healthy girl, which suffered from an acute Libman-Sacks-Endocarditis, are presented.

Atrial reentrant tachycardia after surgery for congenital heart disease: endocardial mapping and radiofrequency catheter ablation using a novel, noncontact mapping system.

BACKGROUND: The purpose of the present study was to determine the role of a novel, noncontact mapping system for assessing a variety of atrial reentrant tachycardias (ART) in patients after the surgical correction of congenital heart disease. METHODS AND RESULTS: In 14 patients, an electrophysiological study using the Ensite 3000 system was performed to assess ARTs resistant to medical treatment. Sixteen different forms of ART were inducible in the 14 patients studied. The reentrant circuit of all ARTs could be characterized and localized with respect to anatomic landmarks such as atriotomy scars, intraatrial patches/baffles, and cardiac structures. In 15 of the 16 ARTs (in 13 of the 14 patients), a target area of the reentrant circuit for radiofrequency current application (ie, an area of conduction between 2 anatomical obstacles such as surgical barriers and cardiac structures of electrical isolation) could be localized within the systemic venous atrium. Nine patients exhibited macroreentry, and 4 showed microreentry. In 12 patients, ART could be terminated by creating linear radiofrequency current lesions (75 degrees C, 180 to 390 s). Completeness of linear lesions after radiofrequency current delivery was proven by analyzing color-coded isopotential maps of atrial activation while applying atrial pacing techniques. The mean duration of the procedures was 286 minutes (range, 130 to 435 minutes); fluoroscopy time ranged from 7 to 33.8 minutes (mean, 17.4 minutes). CONCLUSIONS: In patients with ART after the surgical correction of congenital heart disease, the use of the noncontact mapping system allows for characterization of the tachycardia and guidance for effective radiofrequency current delivery.

Abbreviated combined anatomical/electrophysiological approach for catheter ablation of atrioventricular nodal reentrant tachycardia in children.

Atrioventricular nodal reentrant tachycardia was proven during electrophysiologic study in 41 children, aged from 3.7 to 16 years, who were referred for catheter ablation of symptomatic supraventricular tachycardia. Using an abbreviated combined anatomical and electrogram-guided approach for selective ablation of the slow pathway, a steerable ablation catheter was placed at the inferior region of the vestibule of the tricuspid valve close to the orifice of the coronary sinus, with the intention of recording a multicomponent local atrial electrogramm during sinus rhythm. If application of radiofrequency current of 500 kHz at 70 degrees C at this site did not result in a slowly accelerated junctional rhythm, at a rate of less than 120 beats per minute, the catheter was stepwise advanced up to a position midway towards the apex of the triangle of Koch for additional applications of energy. Ablation was achieved in 35 of the patients. In 6 patients, the slow pathway was modulated such that the tachycardia could no longer be induced. The number of applications of energy ranged from 1 to 19, with a median of 6 applications. The mean period of fluoroscopy was reduced to 15.6 (4.3 to 39.8) minutes, while the overall duration of the catheterization procedures ranged from 88 to 280 (mean 173.2) minutes. In none of the patients did we observe permanent high grade atrioventricular block. During follow-up over a mean of 4.1 years, two patients had recurrence of tachycardia, corresponding to a 95% rate of success in the midterm. We conclude that selective radiofrequency ablation of the slow pathway using the abbreviated anatomical and electrophysiological approach is a safe and curative therapeutic approach in children with atrioventricular nodal reentrant tachycardia. Periods required for fluoroscopy can be significantly reduced, and mid-term results are excellent.

[Atrioventricular nodal reentry tachycardia in children: curative treatment by high frequency catheter ablation]. / AV-Knoten-Reentry-Tachykardien im Kindesalter: Kurative Behandlung durch Hochfrequenzstromablation.

BACKGROUND: Atrioventricular nodal reentrant tachycardia (AVNRT) is one of the most common forms of supraventricular tachycardia in the pediatric population. PATIENTS AND METHODS: 41 children with a mean age of 9.6 (3.7-16) years with recurrent atrioventricular nodal reentrant tachycardia (AVNRT) refractory to medical treatment (n = 38) and recurrent syncope (n = 3) underwent electrophysiologic (EP) study. In all patients dual AV-nodal physiology could be demonstrated during EP study and typical form of AVNRT (mean heart rate 220/min) could be induced by programmed atrial stimulation. A steerable 7 F ablation catheter was placed at the inferoparaseptal region of the tricuspid valve annulus close to the orifice of the coronary sinus with the intention to record a late fractionated local atrial electrogram during sinus rhythm. Starting at this point radiofrequency current (500 kHz) with a target temperature of 70 degrees C was delivered with the intention to ablate the slow pathway. If a slowly accelerated junctional rhythm (< 120/min) occurred during energy discharge, programmed atrial stimulation was repeated. Otherwise radiofrequency current was delivered step by step up to a septal position next to the tricuspid valve annulus. Slow pathway ablation was defined as lack of evidence of dual AV nodal pathways during repeated atrial stimulation. Slow pathway modulation was defined as maximal one atrial echoimpulse after ablation. RESULTS: The number of energy applications ranged from 1-19 (median 6). In 35/41 patients slow pathway ablation could be achieved; in six patients the slow pathway was modulated. In none of the patients permanent high grade AV block was observed. During follow-up (mean 4.1 years) two patients had a recurrent episode of AVNRT after slow pathway modulation. All other patients are still free of AVNRT without medical treatment. CONCLUSION: Selective radiofrequency current ablation/modulation of the slow pathway is a safe and curative treatment of AVNRT in young patients.

[Supraventricular tachycardia in infants, children and adolescents: diagnosis, drug and interventional therapy]. / Supraventrikuläre Tachykardien bei Säuglingen, Kindern und Jugendlichen: Diagnostik--Medikamentöse und interventionelle Therapie.

Supraventricular tachycardias are the most frequent forms of symptomatic tachyarrhythmias in infants, children and adolescents. Clinical symptoms depend on age and underlying cardiac anatomy. Newborn babies and infants with paroxysmal atrioventricular reentrant tachycardias usually present with signs of congestive heart failure due to rapid heart rate. In older children and adolescents, palpitations are the leading symptom. Patients with chronic-permanent tachycardias (i.e., atrial ectopic tachycardia, permanent form of junctional reciprocating tachycardia) often develop a secondary form of dilated cardiomyopathy, the so-called "tachymyopathy". Adenosine has evolved as the drug of choice in any age group for the termination of atrioventricular reentrant tachycardia of any origin. In addition, it serves as a diagnostic tool in primary atrial tachycardias. Long-term management of atrioventricular reentrant tachycardia in infancy and childhood is age dependent. In newborn babies and infants, pharmacological therapy is advised due to the high spontaneous cessation rate of those tachycardias at the end of the first year of life. In contrast to this, the probability of spontaneous cessation of tachycardia in children > 1 year of age is very low. Therefore, radiofrequency catheter ablation of the anatomical substrate of the tachycardia is a rational alternative to long-lasting antiarrhythmic therapy. Results in children with a structurally normal heart are comparable to those achieved in adults. In patients with congenital heart disease and supraventricular tachycardias, catheter ablation during preoperative cardiac catheterization is recommended. Atrial reentrant tachycardias have been identified as one major risk factor for late postoperative morbidity and mortality in young patients. Pharmacological therapy is often not sufficient to control the tachycardia. In addition, underlying sinus node dysfunction may be aggravated in a considerable portion of the patients affected. Catheter ablation based on conventional endocardial mapping techniques by multipolar electrode catheters with the aim of identifying the critical region of the reentrant circuit is associated with an impaired success rate and a considerable recurrence rate. It may be assumed that, using the modern mapping techniques currently available (electroanatomical mapping and non-contact mapping), results of radiofrequency catheter ablation of atrial reentrant tachycardias after surgical correction of congenital heart disease will be significantly improved within the next few years.