title: How revealing are insertable loop recorders in pediatrics?
abstract: BACKGROUND
  An insertable loop recorder (ILR) in patients with infrequent syncope or palpitations may be useful to decide management strategies, including clinical observation, medical therapy, pacemaker, or implantable cardioverter defibrillator (ICD). We sought to determine the diagnostic utility of the Reveal ILR (Medtronic, Inc., Minneapolis, MN, USA) in pediatric patients.
  
  
  METHODS
  Retrospective review of clinical data, indications, findings, and therapeutic decision in 27 consecutive patients who underwent ILR implantation from 1998-2007.
  
  
  RESULTS
  The median age was 14.8 years (2-25 years). Indications were syncope in 24 patients and recurrent palpitations in three. Overall, eight patients had structural heart disease (six congenital heart disease, one hypertrophic cardiomyopathy, one Kawasaki), five had previous documented ventricular arrhythmias with negative evaluation including electrophysiology study, and three patients had QT prolongation. Tilt testing was performed in 10 patients, of which five had neurocardiogenic syncope but recurrent episodes despite medical therapy. After median three months (1-20 months), 17 patients presented with symptoms and the ILR memory was analyzed in 16 (no episode stored in one due to full device memory), showing asystole or transient atrioventricular (AV) block (2), sinus bradycardia (6), or normal sinus rhythm (8). Among asymptomatic patients, 3/10 had intermittent AV block or long pauses, automatically detected and stored by the ILR. In 19 of 20 patients, ILR was diagnostic (95%) and five subsequently underwent pacemaker implantation, while seven patients remained asymptomatic without ILR events. Notably, no life-threatening events were detected. The ILR was explanted in 22 patients after a median of 22 months, two due to pocket infection, 12 for battery depletion and eight after clear documentation of nonmalignant arrhythmia.
  
  
  CONCLUSIONS
  The ILR in pediatrics is a useful adjunct to other diagnostic studies. Patient selection is critical as the ILR should not be utilized for malignant arrhythmias. A diagnosis is attained in the majority of symptomatic patients, predominantly bradyarrhythmias including pauses and intermittent AV block.
authors.affiliation: Department of Cardiology, Children's Hospital Boston, Boston, Massachusetts 02115, USA.
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Frangini
authors.forename: Frank
authors.initials: F
authors.lastname: Cecchin
authors.forename: Ligia
authors.initials: L
authors.lastname: Jordao
authors.forename: Maria
authors.initials: M
authors.lastname: Martuscello
authors.forename: Mark E
authors.initials: ME
authors.lastname: Alexander
authors.forename: John K
authors.initials: JK
authors.lastname: Triedman
authors.forename: Edward P
authors.initials: EP
authors.lastname: Walsh
authors.forename: Charles I
authors.initials: CI
authors.lastname: Berul
mesh_terms: D000293:Adolescent; D000368:Aged; D002648:Child; D002675:Child, Preschool; D015716:Electrocardiography, Ambulatory / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D016247:Information Storage and Retrieval / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010372:Pediatrics / Q000295:instrumentation; D019736:Prostheses and Implants; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation*; D013575:Syncope / Q000175:diagnosis*