Use of the implantable loop recorder in children and adolescents

Recurrent but infrequent syncopes represent a diagnostic challenge, since they frequently remain unexplained despite extensive investigations. This applies specifically for patients who carry an increased risk of potentially lifethreatening arrhythmias, either due to congenital cardiac disease or primary electrical disorders. Implantable loop recorders permit long-term electrocardiographic monitoring. Experience with these devices is still limited in children.

Between January 1999 and August 2005, 12 patients underwent implantation of a loop recorder in our tertiary referral centre. The mean age was 10.9 years, with a range from 2 to 17 years. Of the patients, 6 had structural disease, 3 had primary electrical abnormalities, and 3 had no cardiovascular disease.

Resyncope occured in 9 of the 12 patients. Arrhythmic origin of the syncope was diagnosed in 4 of these patients. The events recorded were ventricular fibrillation in 2, intermittent asystole in 1, and pacemaker-syndrome in the other patient. Malignant arrhythmia was ruled out in the remaining 5 patients. There were no complications related to implantation of the loop recorder, and the mean duration until explantation was 8.3 months.

Based on our experience, we suggest that implantation of a loop recorder represents an additional tool for a selected group of children. Due to its invasive nature, it should be restricted to patients at high risk, or those in which there is substantial clinical suspicion of the likelihood of serious arrhythmias when conventional testing has been inconclusive. In this cohort, implantation of the loop recorder either helps to establish the correct diagnosis, or to exclude an arrhythmic event, thus avoiding unnecessary escalation of therapy and providing reassurance for the family.