use propranolol for refractory VT

The patient has evidence for refractory VT, a serious condition that is sometimes called “electrical storm” and is variably defined. Common definitions distinguish between patients with an implantable cardiac defibrillator and patients without an implantable cardiac defibrillator. The shared features of usual definitions of electrical storm include recurrence of ventricular arrhythmias requiring treatment within a short period of time. Common definitions suggest greater than two to three episodes of sustained ventricular arrhythmia within 24 h. The fundamental principles involved are (1) controlling the acute arrhythmia, (2) addressing the underlying problem, and (3) managing the high sympathetic tone associated with the arrhythmias and their treatment. In rare cases, urgent ablation of the arrhythmogenic locus may be attempted.

The usual antiarrhythmic therapies for sustained monomorphic VT include amiodarone (albeit with acknowledgment of the risks of amiodarone toxicity with long-term use), dofetilide, and lidocaine, with amiodarone generally preferred. In certain circumstances (eg, Brugada syndrome), isoproterenol has been recommended. The use of amiodarone in this case was reasonable. Since the patient has normal electrolytes, pulmonary edema that has been resolved, and a nonischemic cardiomyopathy, a primary additional focus is on managing the high catecholamine state observed in electrical storm. Data from observational cohorts and a small randomized controlled trial provide reasonable evidence for the use of β-blockade as an adjunct for primary antiarrhythmic therapy. In addition, the randomized controlled trial demonstrated that the nonselective β-antagonist propranolol is superior to metoprolol.

While sotalol is a potent antiarrhythmic and has some β-blocking properties, there is neither evidence nor expert consensus to support its utility in this situation.

Although some authors recommend digitalis in certain patients with atrial fibrillation or emphasize its potential noncatecholamine inotropic features, there is no role for digitalis in refractory ventricular arrhythmias.

While isoproterenol is recommended for electrical storm in patients with Brugada syndrome, there is no evidence that this patient has Brugada syndrome, as manifested by her heart failure with reduced ejection fraction and lack of coving of ST segments.1234

A 48-year-old woman with heart failure with reduced ejection fraction due to nonischemic cardiomyopathy is admitted to the ICU with symptomatic pulmonary edema, requiring noninvasive ventilation and IV furosemide. She recovers from the pulmonary edema and is comfortably breathing ambient air. ECG reveals a QRS of 120 m/s without ischemic features or coving of ST segments. She develops unstable monomorphic ventricular tachycardia and is synchronously cardioverted using 100 J. IV amiodarone is administered. Serum electrolytes are within normal limits. Two h later, she develops unstable monomorphic ventricular tachycardia (VT), is again cardioverted, and receives an additional IV bolus of amiodarone. Five h later, she again develops unstable VT with the same morphology as the prior episodes.

Early IV administration of which agent is most likely to improve outcomes in the management of this patient’s arrhythmia?

Footnotes

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  2. Chatzidou S, Kontogiannis C, Tsilimigras DI, et al. Propranolol versus metoprolol for treatment of electrical storm in patients with implantable cardioverter-defibrillator. J Am Coll Cardiol. 2018;71(17):1897-1906. PubMed ↩

  3. Eifling M, Razavi M, Massumi A. The evaluation and management of electrical storm. Tex Heart Inst J. 2011;38(2):111-121. PubMed ↩

  4. Nademanee K, Taylor R, Bailey WE, Rieders DE, Kosar EM. Treating electrical storm : sympathetic blockade versus advanced cardiac life support-guided therapy. Circulation. 2000;102(7):742-747. PubMed ↩