Correlation in Young Patients With Syncope and Palpitations Efficacy of Implantable Loop Recorders in Establishing Symptom-Rhythm

Objective. To evaluate efficacy of the recently introduced implantable loop recorder (ILR) in establishing symptom-rhythm correlation in young patients with syncope, near syncope, palpitations, and acute life-threatening events (ALTEs). Methods. A retrospective study was conducted with patients with ILR from 3 pediatric centers. Inclusion criteria were age <25 years and a minimum follow-up of 1 month. All ILR-stored events were analyzed regularly for the presence or absence of an arrhythmia at the time of the symptomatic event. Results. Twenty-one patients (12 male, 9 female) with an average age of 12.3 5.3 years (range: 0.8–22 years) were included in the study. Five (24%) patients had structural heart disease, 2 (10%) had a family history of sudden cardiac death, 3 (14%) had QT prolongation on electrocardiogram, and 11 had no cardiovascular disease. Indications for ILR were recurrent syncope and near syncope (n 15), palpitations (n 2), and ALTE (n 2). Fourteen (67%) patients continued to have symptoms, and 7 (33%) had no symptoms after ILR over a follow-up period of 8.4 4.7 months (range: 1.9–16 months). Symptom-rhythm correlation was possible in all 14 patients who continued to have symptoms (supraventricular tachycardia in 4, ventricular tachycardia in 2, torsades de points in 1, asystole in 1, junctional bradycardia in 1, and sinus rhythm in 5). Conclusions. ILR is useful in determining the presence or absence of an arrhythmia during symptoms of syncope, near syncope, and palpitations as well as ALTEs in patients with and without structural heart disease when conventional diagnostic testing, such as electrocardiogram, Holter monitoring, and/or external loop recording, is inconclusive. Pediatrics 2003;112:e228–e233. URL: http://www.pediatrics.org/cgi/content/full/112/3/e228; implantable loop recorder, arrhythmias, syncope, palpitations. ABBREVIATIONS. HUT, head-up tilt; ECG, electrocardiogram; ELR, external loop recorder; EPS, electrophysiology study; ILR, implantable loop recorder; ALTE, acute life-threatening event; EEG, electroencephalogram; SVT, supraventricular tachycardia; VT, ventricular tachycardia; RFA, radiofrequency ablation; LQTS, long QT syndrome. Syncope, near syncope, and palpitations are common symptoms in the pediatric population. These events are frequently a source of concern and anxiety among patients and parents. It is estimated that at least 1 episode of syncope is experienced in 30% of patients by adolescence. Although syncope in children is generally a benign event, in some circumstances, it can herald a potentially lethal problem.2,3 Finding the underlying cause is important for risk stratification as well as for rendering appropriate therapy. Neurocardiogenic syncope, the most common cause of syncope in young patients, can be diagnosed by a detailed history alone and sometimes warrants a head-up tilt (HUT) test. When other causes are suspected, conventional cardiovascular testing with an electrocardiogram (ECG), ambulatory Holter monitoring, and external loop recorders (ELRs) is implemented. An echocardiogram is performed when structural heart disease is suspected.4 An electrophysiology study (EPS) is rarely needed in a child with syncope. Unfortunately, conventional cardiovascular tests have a low diagnostic yield.5–7 The main reason for the reduced diagnostic efficacy of these tests is the difficulty of obtaining symptom-rhythm correlation, when symptoms are unpredictable and infrequent. An ECG at the time of the symptomatic event is the logical gold standard to diagnose or exclude an arrhythmia as the cause of symptoms. However, ambulatory Holter monitoring is generally brief (24–48 hours) and patients are often not symptomatic during this time. The usefulness of the ELR may be limited because of resolution of symptoms by the time the device is activated.6,7 Recent advances in loop recording technology have led to the development of an implantable loop recorder (ILR; Reveal Plus; Medtronic, Minneapolis, MN) that is active for at least 14 months. This device incorporates a continuous loop recording of the heart rhythm that is stored when the device is activated by the patient, parent, or surrogate. There is also an autoactivation component that allows the device to record rhythms automatically if a patient’s heart rate exceeds or goes below a preset limit. Use of this technology in children may increase the probability of making an accurate diagnosis and avoiding other extensive and repetitive testing. From the *Department of Pediatrics, University of Washington School of Medicine, Seattle, Washington; ‡Department of Pediatrics, Wilhelmina Children’s Hospital; and §Department of Pediatrics, Oregon Health Sciences University. Dr Rossano and Beatrijs Bloemers made equal contributions and should be considered first authors. Received for publication Oct 31, 2002; accepted Apr 24, 2003. Reprint requests to (M.J.S.) Department of Cardiac Pacing and Electrophysiology, Heart Center, Children’s Hospital, 4800 Sandpoint Way NE, Seattle, WA 98105. E-mail: [email protected] PEDIATRICS (ISSN 0031 4005). Copyright © 2003 by the American Academy of Pediatrics. e228 PEDIATRICS Vol. 112 No. 3 September 2003 http://www.pediatrics.org/cgi/content/full/112/3/e228 at UNIV OF CHICAGO on May 3, 2013 pediatrics.aappublications.org Downloaded from