Radiofrequency Catheter Ablation in Small Children:

Abstract

Little data exists to support the use of procedural modifications during radiofrequency catheter ablation (RFCA) in small children. A single institution database was reviewed for patients under 15 kg undergoing RFCA from January 1998 to August 2001. Of 268 RFCA procedures, 18 were done in 14 patients under 15 kg (median weight 5.7 kg, 3.5-13.7; age 5.8 months, 1.2-19.8). Six patients had normal hearts, 4 had congenital heart disease, and 4 patients had cardiomyopathy. Diagnoses were orthodromic reciprocating tachycardia (ORT) in nine patients/nine studies, chaotic atrial tachycardia (CAT) in one patient/two studies, and VT in four patients/seven studies. RFCA variables included maximum temperature (69 degrees C, 50-78), total applications (10, 2-21), applications > 20 seconds (5, 0-15), and total application time (331 s, 26-1,006 s). Complications were pericardial effusion in 1 patient, mild mitral regurgitation in 1, and myocardial infarction in 1 patient. When indexed for weight, the number of applications with a duration > 20 seconds in the ORT group was significantly greater in complicated versus uncomplicated procedures (0.7 applications/kg vs 0.16 applications/kg, P = 0.05). In addition, for the ORT subgroup, the indexed total application time trended higher in complicated versus uncomplicated procedures (40.6 s/kg, vs 6.6 s/kg, P = 0.1). RFCA success was 9/9 in ORT, 6/7 in VT, and 0/2 in CAT. RFCA can be successful in small children; however, complications appear to be related to RF dose indexed for body size. Thus, the decision to proceed with RFCA, and the application duration and number should be guided by patient size, balanced against the risks of the arrhythmia, and reserved for dire circumstances.

Catheter ablation of drug resistant supraventricular tachycardia in neonates and infants

“…In the pediatric ablation registry, the average fluoroscopy time for ablation of SVT is 40 min [21]. With newborns and infants, this time can extend to up to 194 min [6,7,17]. When we used the 3D mapping system, the average time of fluoroscopy was only 4 min.…”

“…Although the number of studies focusing on the use of RFA to manage SVT in neonates and infants increases by the day, the topic remains controversial [2][3][4][5][6][7][8]. According to the Pediatric Radiofrequency Ablation (RFCA) registry data from 1991-1997, body weight of less than 15 kg poses a significant risk of complications during RFA, including AV block, cardiac perforation and even death [5].…”

“…If these fail, other antiarrhythmic agents like amiodarone, flecainide, propafenone and sotalol are added or used in combination [1,2,13]. If SVT persists despite conventional pharmacologic therapy and is complicated by ventricular dysfunction, catheter ablation can be used for definitive treatment [2][3][4][5][6][7].…”

“…Additionally, the potential progressive nature of RFA lesions can also increase complication rates in younger patients [6][7][8][9][10][11]. In order to minimize or altogether avoid these complications, RFA should be performed by an experienced pediatric electrophysiologist who can reduce risk by varying power, temperature, application duration and number of attempts depending on the patient's size [6,7]. In our study, catheter ablation was carried out by an experienced pediatric electrophysiologist, and no major complications were seen.…”

“…In many centers, catheter ablation has become standard treatment of SVT in adolescents with symptomatic tachycardia [4,5]. Although RFA has been used to treat SVT in younger patients and infants, it has generally been reserved for cases of life-threatening medically refractory tachyarrhythmia [3,6,7]. Due to low patient age and weight, concomitant congenital heart diseases and excessive application of radiofrequency (RF) energy, RFA has been linked to increased morbidity and mortality [4,8,9].…”