title: Utility of implantable loop recorders for diagnosing unexplained syncope in clinical practice.
abstract: BACKGROUND
  Establishing a symptom-rhythm correlation in patients with unexplained syncope is complicated because of its sporadic, infrequent, and unpredictable nature. Prolonged monitoring with an implantable loop recorder (ILR) allows the recording of electrocardiogram (ECG) data from a spontaneous syncopal event.
  
  
  OBJECTIVE
  The aim of this study was to evaluate the usefulness of the ILR for the diagnosis of syncope of unknown origin after conventional management in clinical practice.
  
  
  METHODS
  We reviewed the results with ILR implantation in patients with syncope of unknown origin after conventional management in the cardiology department at HU Marques de Valdecilla (Santander, Cantabria, Spain).
  
  
  RESULTS
  One hundred and forty patients (age 64 +/- 16 y; 86 male [62%]) with syncope of unknown etiology after conventional work-up underwent prolonged monitoring with an ILR from September 1998 to February 2006; 46 patients (33%) had structural heart disease. During a mean follow-up of 346 +/- 160 d, 51 patients (36.5%) had recurrent syncope with diagnostic ECG recording. An arrhythmic cause for syncope was found in 33 of them (64.5%), with bradycardia present in 27 (53%) and tachycardia in 6 (11%). There were no sudden deaths, and 1 patient suffered a complication related to a recurrence of syncope.
  
  
  CONCLUSIONS
  Long-time experience with the ILR confirmed the utility of this device in the diagnosis of unexplained syncope in clinical practice. Most of these patients had syncope of arrhythmogenic etiology that could be successfully treated. This strategy of prolonged monitoring is safe even in patients with structural heart disease.
authors.affiliation: Cardiology Department, HU Marqués de Valdecilla, Santander, Cantabria, Spain. fentem@eurodivisas.com
authors.forename: Felipe R
authors.initials: FR
authors.lastname: Entem
authors.forename: Susana G
authors.initials: SG
authors.lastname: Enriquez
authors.forename: Manuel
authors.initials: M
authors.lastname: Cobo
authors.forename: Víctor
authors.initials: V
authors.lastname: Expósito
authors.forename: Miguel
authors.initials: M
authors.lastname: Llano
authors.forename: Marta
authors.initials: M
authors.lastname: Ruiz
authors.forename: Juan
authors.initials: J
authors.lastname: Jose Olalla
authors.forename: Macarena
authors.initials: M
authors.lastname: Otero-Fernandez
mesh_terms: D001145:Arrhythmias, Cardiac / Q000175:diagnosis; D015716:Electrocardiography, Ambulatory / Q000295:instrumentation / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D013575:Syncope / Q000175:diagnosis*