title: Prevalence, predictors, and mortality significance of the causative arrhythmia in patients with electrical storm.
abstract: BACKGROUND
  Electrical storm (ES) is characterized by either refractory ventricular tachycardia (VT) or ventricular fibrillation (VF). However, little is known about the prevalence, predictors, and mortality implications of the causative arrhythmia in ES. We sought to assess the prevalence, predictors, and survival significance of VT and VF as the causative arrhythmia of ES in implantable cardioverter defibrillator (ICD) patients.
  
  
  RESULTS
  Consecutive patients from January 2000 to December 2002 who presented to the ICD clinic with > or = 2 separate ventricular arrhythmic episodes requiring shock within 24 hours were included in the study. ICD interrogation confirmed the number of shocks and provided electrograms for interpretation of the causative arrhythmia. Patients were grouped as VF or VT according to the causative arrhythmia. Their prevalence, predictors, and mortality rates were compared. Of 2,028 patients assessed in the ICD clinic, 208 (10%) presented with ES. VF was the cause of ES in 99 of 208 patients, for an overall prevalence of 48%. Original ICD indication, coronary artery disease, and amiodarone therapy were predictive for the causative arrhythmia. There was no mortality difference between the VT and VF groups; however, both groups had significantly increased mortality compared to a control ICD population without ES.
  
  
  CONCLUSIONS
  VF is the causative arrhythmia for a sizable proportion of patients with ES. The initial ICD indication, coronary artery disease, and amiodarone therapy are predictors of the causative arrhythmias in ES. There does not appear to be any mortality difference between ES patients with VT and VF, but mortality is increased in patients with ES versus control ICD patients without ES.
authors.affiliation: Cleveland Clinic Foundation, Section of Pacing and Electrophysiology, Cleveland, Ohio 44195, USA.
authors.forename: Atul
authors.initials: A
authors.lastname: Verma
authors.forename: Fethi
authors.initials: F
authors.lastname: Kilicaslan
authors.forename: Nassir F
authors.initials: NF
authors.lastname: Marrouche
authors.forename: Stephen
authors.initials: S
authors.lastname: Minor
authors.forename: Mohammed
authors.initials: M
authors.lastname: Khan
authors.forename: Oussama
authors.initials: O
authors.lastname: Wazni
authors.forename: J David
authors.initials: JD
authors.lastname: Burkhardt
authors.forename: William A
authors.initials: WA
authors.lastname: Belden
authors.forename: Jennifer E
authors.initials: JE
authors.lastname: Cummings
authors.forename: Ahmad
authors.initials: A
authors.lastname: Abdul-Karim
authors.forename: Walid
authors.initials: W
authors.lastname: Saliba
authors.forename: Robert A
authors.initials: RA
authors.lastname: Schweikert
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Tchou
authors.forename: David O
authors.initials: DO
authors.lastname: Martin
authors.forename: Andrea
authors.initials: A
authors.lastname: Natale
mesh_terms: D000368:Aged; D001145:Arrhythmias, Cardiac / Q000150:complications* / Q000401:mortality; D017147:Defibrillators, Implantable / Q000009:adverse effects; D005260:Female; D006801:Humans; D008297:Male; D015995:Prevalence; D011379:Prognosis; D012008:Recurrence; D016019:Survival Analysis; D017180:Tachycardia, Ventricular / Q000209:etiology* / Q000401:mortality; D014693:Ventricular Fibrillation / Q000209:etiology* / Q000401:mortality