Successful transcatheter cryoablation in infants with drug-resistant supraventricular tachycardia: a case series

Outcomes of interventional electrophysiology in children under 2 years of age

BACKGROUND

Despite the increasing utilisation of interventional electrophysiology in adults and older children with arrhythmias, there are few data reflecting the safety and efficacy of this procedure in the age group under 2 years.

AIM

We describe our experience in assessing the efficacy and safety with this group of children.

METHODS

We undertook a retrospective review of all infants under 2 years of age who underwent an interventional electrophysiology procedure between 1995 and 2009 to determine indications, procedural details, short- and long-term success, and complication rate.

RESULTS

A total of 23 interventional electrophysiology procedures were performed in 17 patients initially under 2 years of age. Of these, three patients had congenital heart disease. The most common indication was arrhythmia resistant to pharmacological agents (59%), with the remaining cases being arrhythmia complicated by cardiovascular instability (41%). There was initial success in 15 patients after the first procedure, with early recurrence in four. Following six repeat procedures, there was long-term success in 15 patients (88%), with three repeat procedures being performed after 2 years of age. There was one non-procedural death related to persisting arrhythmia. There were three minor complications. In one patient, cryotherapy was used successfully.

CONCLUSIONS

The interventional electrophysiology procedure is a viable therapeutic option in infants under 2 years with arrhythmia resistant to other conventional medical management.

Safety and results of cryoablation in patients <5 years old and/or <15 kilograms

Current recommendations discourage elective radiofrequency ablation in patients <5 years old and/or weighing <15 kg, primarily because of the greater complication rate. To describe the current use, complications, and immediate outcomes of cryoablation in this patient population, a multicenter retrospective review of all patients <5 years old and/or weighing <15 kg who were treated with cryoablation for arrhythmia was performed. Eleven centers contributed data for 68 procedures on 61 patients. Of those, 34% were elective and 24% (n = 16) were both cryoablation and radiofrequency ablation. The median age and weight at ablation was 3.5 years (range 8 days to 9.9 years) and 15.2 kg (range 2.3 to 23), respectively. Congenital heart disease was present in 23% of the patients. The immediate success rate of cryoablation alone was 74%. No major complications occurred with cryoablation only; however, 2 of the 16 patients who underwent cryoablation and radiofrequency ablation had major complications. Of the 50 patients receiving cryoablation, 8 (16%) had variable degrees of transient atrioventricular block. The recurrence rate was 20% after cryoablation and 30% after cryoablation plus radiofrequency ablation. In conclusion, cryoablation appears to have a high safety profile in these patients. Compared to older and larger patients, the efficacy of cryoablation in this small, young population was lower and the recurrence rates were higher. Cryoablation's effect on the coronary arteries has not been fully elucidated and requires additional research.