title: Incidence of arrhythmias in a large cohort of patients with current implantable cardioverter-defibrillators in Spain: results from the UMBRELLA Registry.
abstract: OBJECTIVE
  The benefit of implantable cardioverter-defibrillators (ICDs) in patients at risk of sudden death has been established in randomized clinical trials (RCTs) using the ICD models available at the time. However, observational large-scale data on the incidence of arrhythmias in up-to-date ICDs implanted according to the current guidelines are scarce. The aim was to assess the incidence of arrhythmias in a large, current ICD population based on a blinded peer review of the detected episodes.
  
  
  RESULTS
  UMBRELLA is a multicentre, observational registry of ICD patients followed by remote monitoring. Stored episodes were classified by a blinded committee of experts. Subgroup analyses were based on clinical profiles established by previous pivotal RCTs of ICDs. Of 1514 enrolled patients, 605 (39.9%) patients had 5951 episodes after 26 ± 17 months follow-up, being 3353 of them (56.3%) sustained ventricular arrhythmias (SVA), and 13.2% of SVA were self-terminated. Appropriate and inappropriate shocks occurred in 11.6 and 5% of patients, respectively. The 3 years cumulative incidence of SVA was 25% (95% CI: 21-28%) in primary prevention patients and 41% (95% CI: 36-47%) in secondary prevention patients (P < 0.001). Male gender, secondary prevention, and atrial fibrillation as basal rhythm were significantly related to a higher incidence of SVA.
  
  
  CONCLUSIONS
  This real-world analysis suggests that modern ICD patients have a low rate of appropriate and inappropriate shocks. The risk of SVA in secondary prevention patients is less than what has been reported in RCTs.
authors.affiliation: University Hospital 12 de Octubre, Av de Córodoba sn, 28041, Madrid, Spain drfontenla@gmail.com.
authors.forename: Adolfo
authors.initials: A
authors.lastname: Fontenla
authors.affiliation: University Hospital of Araba, Calle Jose itxotegi sn, 01009, Vitoria-Gasteiz, Alava, Spain.
authors.forename: Jose B
authors.initials: JB
authors.lastname: Martínez-Ferrer
authors.affiliation: University Hospital Virgen de las Victoria, Campus de Teatinos sn, 29010 Malaga, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Alzueta
authors.affiliation: Hospital de la Santa Creu i Sant Pau, Carrer de Sant Quinti, 89, 08026 Barcelona, Spain.
authors.forename: Xavier
authors.initials: X
authors.lastname: Viñolas
authors.affiliation: University Hospital Virgen de la Arrixaca, Ronda de Levante, 11, 30008 Murcia, Spain.
authors.forename: Arcadi
authors.initials: A
authors.lastname: García-Alberola
authors.affiliation: Hospital Clìnic i Provincial, Carrer Villarroel, 170, 08036 Barcelona, Spain.
authors.forename: Josep
authors.initials: J
authors.lastname: Brugada
authors.affiliation: University Hospital La Paz, Paseo de la Castellana 261, 28046 Madrid, Spain.
authors.forename: Rafael
authors.initials: R
authors.lastname: Peinado
authors.affiliation: University Hospital La Fe, Avenida Campanar, 21, 46026 Valencia, Spain.
authors.forename: Maria J
authors.initials: MJ
authors.lastname: Sancho-Tello
authors.affiliation: Cardiac and Vascular Group, Medtronic Iberica, Calle Maria de Portugal, 9, 28050 Madrid, Spain.
authors.forename: Alicia
authors.initials: A
authors.lastname: Cano
authors.affiliation: University Hospital Puerta de Hierro-Majadahonda, Calle Manuel de Falla, 1, 28222, Majadahonda, Madrid, Spain.
authors.forename: Ignacio
authors.initials: I
authors.lastname: Fernández-Lozano
mesh_terms: D000368:Aged; D058406:Cardiac Resynchronization Therapy / Q000009:adverse effects*; D016757:Death, Sudden, Cardiac / Q000517:prevention & control*; D017147:Defibrillators, Implantable / Q000009:adverse effects*; D005260:Female; D006801:Humans; D015994:Incidence; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011322:Primary Prevention; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012042:Registries; D055502:Secondary Prevention; D013030:Spain; D017180:Tachycardia, Ventricular / Q000453:epidemiology* / Q000209:etiology
keywords: Appropriate shocks; Implantable cardioverter-defibrillator; Inappropriate shocks; Ventricular arrhythmias