PracticeUpdate Cardiology Best of 2018

EDITOR’S PICKS 8

Propranolol vs Metoprolol for Treatment of Electrical Storm in Patients With ICDs Journal of the American College of Cardiology Take-home message • Patients with ICDs and having an electrical storm admitted to the intensive care unit were randomized to receive either oral propranolol or oral metoprolol in conjunction with IV amiodarone. There was a 2.67-times decrease in the incidence of ventricular arrhythmic events and a 2.34-times decreased rate of ICD discharges seen in the propranolol group compared with the metoprolol group. After 24 hours of treatment, 90.0% of the propranolol group was free of arrhythmic events vs 53.3% of the metoprolol group (P = .03). Patients in the metoprolol group were 77.5% less likely than those in the propranolol group to achieve the termination of arrhythmic events (P < .001). Both the time to termination of the arrhythmia and the length of admission were significantly shorter in the propranolol-treated patients compared with the metoprolol-treated patients. • Among patients with an ICD and suffering an electrical storm receiving IV amiodarone, the addition of oral propranolol is superior to the addition of oral metoprolol.

COMMENT

By Anisiia Doytchinova MD and Peng-Sheng Chen MD S ympathetic activation has long been known to promote ventricu- lar arrhythmogenesis. However, except for a few case reports, there have been little data evaluating specific beta-blocker regimens for the treatment of electrical storm. The study by Chatzi- dou et al is a double-blind randomized clinical trial, which compared proprano- lol (40 mg orally every 6 h) vs metoprolol (50 mg orally every 6 h) for the acute treatment of electrical storm in patients who had already received intravenous amiodarone. The results demonstrated that the propranolol group had 2.67 times reduced incidence of ventricu- lar arrhythmias, 2.34 times reduced incidence of implantable cardiovert- er-defibrillator (ICD) discharges, and shorter hospital length of stay. During the 2-month follow up, no electrical storm recurrences or patient deaths were observed in either study arm. The beneficial effects of propranolol may stem from its ß2 effects by prevent- ing epinephrine-induced hypokalemia associated with ß2 receptor activa- tion. In addition, propranolol has been demonstrated to have a direct blocking effect on both the peak and the late (persistent) sodium current, which may also be anti-arrhythmic. Although the authors do not address whether pro- pranolol offers additional benefits over metoprolol beyond the acute treatment phase, this study represents significant advancement in the treatment of elec- trical storm with immediate potential applications to clinical care.

" …this study represents

Abstract BACKGROUND Electrical storm (ES), character- ized by unrelenting recurrences of ventricular arrhythmias, is observed in approximately 30% of patients with implantable cardioverter-de- fibrillators (ICDs) and is associated with high mortality rates. OBJECTIVES Sympathetic blockade with β-block- ers, usually in combination with intravenous (IV) amiodarone, have proved highly effective in the suppression of ES. In this study, we com- pared the efficacy of a nonselective β-blocker (propranolol) versus a β1-selective blocker (metoprolol) in the management of ES. METHODS Between 2011 and 2016, 60 ICD patients (45 men, mean age 65.0 ± 8.5 years) with ES developed within 24 h from admission were randomly assigned to therapy with either propranolol (160 mg/24 h, Group A) or metopr- olol (200 mg/24 h, Group B), combined with IV amiodarone for 48 h. RESULTS Patients under propranolol therapy in comparison with metoprolol-treated individuals presented a 2.67 times decreased incidence rate (incidence rate ratio: 0.375; 95% confidence interval: 0.207 to 0.678; p = 0.001) of ventricular arrhythmic events (tachycardia or fibrillation) and a 2.34 times decreased rate of ICD discharges (inci- dence rate ratio: 0.428; 95% CI: 0.227 to 0.892; p = 0.004) during the intensive care unit (ICU) stay, significant advancement in the treatment of electrical stormwith immediate potential applications to clinical care. "

after adjusting for age, sex, ejection fraction, New York Heart Association functional class, heart fail- ure type, arrhythmia type, and arrhythmic events before ICU admission. At the end of the first 24-h treatment period, 27 of 30 (90.0%) patients in group A, while only 16 of 30 (53.3%) patients in group B were free of arrhythmic events (p = 0.03). The termination of arrhythmic events was 77.5% less likely in Group B compared with Group A (hazard ratio: 0.225; 95% CI: 0.112 to 0.453; p < 0.001). Time to arrhythmia termination and length of hospital stay were significantly shorter in the propranolol group (p < 0.05 for both). CONCLUSIONS The combination of IV amiodar- one and oral propranolol is safe, effective, and superior to the combination of IV amiodarone and oral metoprolol in the management of ES in ICD patients. Propranolol Versus Metoprolol for Treatment of Electrical Storm in Patients With Implanta- ble Cardioverter-Defibrillator. J Am Coll Cardiol 2018 May 01;71(17)1897-1906, S Chatzidou, C Kontogiannis, DI Tsilimigras, et al. www.practiceupdate.com/c/67408

Dr. Dovtchinova is Assistant Professor of Clinical Medicine in the Division of Cardiovascular Health and Disease at the University of Cincinnati in Cincinnati, Ohio. Dr. Chen is Medtronic Zipes Chair in Cardiology, Director at Krannert Institute of Cardiology, and Chief of the Division of Cardiology at Indiana University in Indianapolis, Indiana.

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