title: Premature ventricular complexes as a trigger for ventricular fibrillation.
abstract: OBJECTIVE
  The mechanisms that trigger ventricular fibrillation (VF) are poorly understood. The aim of this study was to analyze the initiation of VF in electrograms stored in implantable cardioverter-defibrillators (ICDs).
  
  
  METHODS
  We analyzed ICD electrograms from patients who had suffered at least one episode of VF.
  
  
  RESULTS
  Of 250 patients with ICDs, 13 (10 male and 3 female, age 49+/-22 years) had at least one episode of VF. The diagnoses were Brugada syndrome (n=4), ischemic heart disease (n=3), dilated cardiomyopathy (n=2), hypertrophic cardiomyopathy (n=1), short-coupled variant of torsades de pointes (n=1), endocardial fibroelastosis (n=1) and idiopathic VF (n=1). In 7 patients, VF was the reason for ICD implantation. Overall, 31 episodes of VF were recorded, including three episodes of arrhythmic storm. In the 7 patients who had more than one episode of VF (within minutes or up to 3 years apart), all episodes started with premature ventricular complexes (PVCs) that had the same morphology and similar coupling intervals. A short-long-short cycle was observed in 2 patients. In 21 episodes, PVCs that did not trigger VF were observed during sinus rhythm. There was no significant difference between them and PVCs that did trigger VF in terms of morphology, coupling interval (409+/-121 ms vs. 411+/-123 ms) or the preceding sinus rhythm RR interval (801+/-233 ms vs. 793+/-230 ms).
  
  
  CONCLUSIONS
  Spontaneous VF in the form of an arrhythmic storm or an isolated episode were triggered by PVCs. On occasions, PVCs preceded VF without triggering it.
authors.affiliation: Unidad de Arritmias, Servicio de Cardiología, Hospital Universitario Virgen de la Arrixaca, El Palmar, Murcia, Spain. juanjosanchezmunoz@me.com
authors.forename: Juan José
authors.initials: JJ
authors.lastname: Sánchez Muñoz
authors.forename: Arcadio
authors.initials: A
authors.lastname: García-Alberola
authors.forename: Juan
authors.initials: J
authors.lastname: Martínez-Sánchez
authors.forename: Pablo
authors.initials: P
authors.lastname: Peñafiel-Verdú
authors.forename: César
authors.initials: C
authors.lastname: Caro-Martínez
authors.forename: Sergio
authors.initials: S
authors.lastname: Manzano-Fernández
authors.forename: Mariano
authors.initials: M
authors.lastname: Valdés Chávarri
mesh_terms: D000328:Adult; D000368:Aged; D004554:Electric Countershock; D004562:Electrocardiography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D014693:Ventricular Fibrillation / Q000209:etiology* / Q000503:physiopathology / Q000628:therapy; D018879:Ventricular Premature Complexes / Q000150:complications* / Q000503:physiopathology / Q000628:therapy