Amiodarone Is Poorly Effective for the Acute Termination of Ventricular Tachycardia - 17/08/11
, Ian S. deSouza, MD b, Daniel K. Nishijima, MD b, Thomas O. Stair, MD c, Gary S. Setnik, MD d, Jeremy N. Ruskin, MD a
Address for correspondence: Keith A. Marill, MD, Massachusetts General Hospital, 55 Fruit Street, Clinics 115, Boston, MA 02114; 617-726-6636, fax 617-724-0917Résumé |
Study objective |
It is hypothesized that intravenous (IV) amiodarone is poorly effective for the acute termination of sustained monomorphic ventricular tachycardia because of the relatively slow onset of its Vaughn-Williams class III effect to prolong myocardial depolarization and the refractory period. This study is designed to determine the effectiveness and safety of IV amiodarone for the termination of sustained monomorphic ventricular tachycardia.
Methods |
A retrospective case series was collected at 4 urban university-affiliated hospitals from September 1996 to April 2005 after institutional review board approval with waiver of informed consent. Emergency department (ED) patients treated with IV amiodarone for ventricular tachycardia were identified by ED treatment and hospital pharmacy billing records, International Classification of Diseases, Ninth Revision discharge codes, and ECG characteristics. All consecutive patients who received at least 150 mg amiodarone in 15 minutes or less for spontaneous sustained monomorphic ventricular tachycardia were eligible for inclusion. Sustained monomorphic ventricular tachycardia was defined as a tachycardia with uninterrupted duration or rapid recurrence despite automatic internal cardiac defibrillator therapy for at least 5 minutes before amiodarone treatment, monomorphic morphology, rate greater than 120 beats/min, QRS duration greater than 120 ms, and subsequently determined to be ventricular tachycardia by ECG criteria (eg, atrioventricular dissociation), implanted device interrogation, or formal electrophysiology study. Measured outcomes included sustained termination of ventricular tachycardia within 20 minutes of initiation of amiodarone infusion and any documented adverse effects. Rates of successful termination and adverse effects and their 95% confidence intervals (CIs) were calculated. The presence or average values of potentially confounding predictors in patients with and without ventricular tachycardia termination after amiodarone were also calculated and compared.
Results |
Thirty-three patients were identified and included. Five patients received electrical therapy within 20 minutes of initiation of amiodarone infusion, and the response to amiodarone was unknown. Twenty-seven of the remaining 28 patients received 150 mg amiodarone, and the rate of successful ventricular tachycardia termination was 8 of 28, 29% (95% CI 13 to 49). Two of 33 patients, 6% (95% CI 1 to 20), required direct current cardioversion for presyncope or hypotension temporally associated with amiodarone treatment.
Conclusion |
IV amiodarone, as currently administered, is relatively safe but ineffective for the acute termination of sustained ventricular tachycardia.
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| Supervising editor: Judd E. Hollander, MD Author contributions: KAM conceived and designed the study and supervised its conduct and data collection. ISD and DKN collected and analyzed data. TOS and GSS assisted and facilitated data collection. JNR analyzed ECGs and assisted with analysis. KAM analyzed the data, performed the statistical analysis, and drafted the manuscript. All authors were involved in revision. KAM takes responsibility for the paper as a whole. Funding and support: There was no external funding or support for this study. The authors have no financial interest in the sale of amiodarone or any competing products or in the companies that produce them. Presented as an abstract at the Society for Academic Emergency Medicine annual meeting, May 2005, New York, NY. Reprints not available from the authors. |
Vol 47 - N° 3
P. 217-224 - mars 2006 Retour au numéro
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