title: [Impact of metoprolol use in the treatment of patients with electrical-storm after cardioverter defibrillators implantation].
abstract: OBJECTIVE
  To explore the effectiveness of the metoprolol dosage adjustment on reducing the incidence of electrical-storm (ES) in patients with Implantable Cardioverter Defibrillators (ICDs).
  
  
  METHODS
  Data from patients with ICD implantation between Jan, 2003 and Jun, 2006 in our hospital were retrospectively analyzed. ES was defined as either ≥ 3 times of ventricular tachyarrhythmias (VTAs) resulting in ICD therapy or VTAs lasting more than 30 s detected by ICD without any therapy within 24 hours.
  
  
  RESULTS
  During a follow-up period of (27.5 ± 21.2) months, ES was recorded in 39 cases [34 males, average age (52.0 ± 13.1) years] out of 119 patients (32.8%) and 9 patients died after ES. During the period of storm attack, ES was successfully controlled in 25/30 patients by various interventions, including predisposing factors corrected in 5 cases, ICD reprogramming and antiarrhythmic drugs therapy optimized in 16 cases (one received intravenous injection of metoprolol), and VTAs eliminated by catheter ablation in 4 cases. ES was spontaneously resolved in the remaining 5 cases. In the chronic phase, 2 patients with Brugada syndrome were treated with Quinidine mono-therapy while the dosage of metoprolol was adjusted in the remaining 23 patients and the dosage of metoprolol was increased gradually from (26.8 ± 13.9) mg/d to (88.9 ± 53.5) mg/d without any adverse effects (9 patients received also oral amiodarone 200 mg/d). Post dosage adjustment, the total VTA episodes [(1.9 ± 1.7) times/month vs. (0.8 ± 0.6) times/month, P = 0.004], incidence of antitachycardia pacing therapies [(4.2 ± 3.8) runs/month vs. (2.3 ± 2.0) runs/month, P = 0.003], as well as electrical cardioversion or defibrillation [(1.1 ± 0.9) times/month vs. (0.4 ± 0.2) times/month, P = 0.001] were significantly decreased. ES was not controlled until a extremely high dosage [225 - 300 (255.3 ± 41.7) mg/d] of metoprolol was reached in the remaining 5 patients.
  
  
  CONCLUSIONS
  Metoprolol use is essential and its dosage should be individualized in the majority of ICD recipients with ES. In approximately 1/6 patients, the dosage of metoprolol should be higher than 200 mg/d.
authors.affiliation: Department of Cardiology, the First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China.
authors.forename: Jin-bo
authors.initials: JB
authors.lastname: Yu
authors.forename: Bing
authors.initials: B
authors.lastname: Yang
authors.forename: Dong-jie
authors.initials: DJ
authors.lastname: Xu
authors.forename: Ming-long
authors.initials: ML
authors.lastname: Chen
authors.forename: Qi-jun
authors.initials: QJ
authors.lastname: Shan
authors.forename: Jian-gang
authors.initials: JG
authors.lastname: Zou
authors.forename: Chun
authors.initials: C
authors.lastname: Chen
authors.forename: Feng-xiang
authors.initials: FX
authors.lastname: Zhang
authors.forename: Xiao-feng
authors.initials: XF
authors.lastname: Hou
authors.forename: Wen-qi
authors.initials: WQ
authors.lastname: Li
authors.forename: Rong
authors.initials: R
authors.lastname: Zhang
authors.forename: Ke-jiang
authors.initials: KJ
authors.lastname: Cao
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000889:Anti-Arrhythmia Agents / Q000008:administration & dosage* / Q000627:therapeutic use; D017147:Defibrillators, Implantable / Q000009:adverse effects*; D004305:Dose-Response Relationship, Drug; D004554:Electric Countershock; D005260:Female; D006801:Humans; D008297:Male; D008790:Metoprolol / Q000008:administration & dosage* / Q000627:therapeutic use; D008875:Middle Aged; D011379:Prognosis; D012189:Retrospective Studies; D017180:Tachycardia, Ventricular / Q000503:physiopathology* / Q000628:therapy; D055815:Young Adult
chemical_list: D000889:Anti-Arrhythmia Agents; D008790:Metoprolol