Background: In 2016 the annual incidence of out-of-hospital cardiac arrest (OHCA) in the United States was roughly 360,000 and 209,000 for in-hospital cardiac arrest (IHCA) (Mozaffarian 2016). Though survival rates are relatively dismal, arrests in the setting of shock amenable rhythms – ventricular fibrillation (VF) and pulseless ventricular tachycardia (VT) – have an overall better rate of return of spontaneous circulation (ROSC). While cardiac defibrillation may be effective in terminating VF/VT, defibrillation does not prevent recurrence of VF/VT. According to the advanced cardiovascular life support (ACLS) algorithm, amiodarone is still the recommended first-line medication for shock refractory VF/VT. These recommendations stem from two hallmark studies which demonstrated improved ROSC and survival rates to admission after amiodarone was administered (Dorian 2002, Kudenchuk 1999). However, ROSC does not represent a clinically meaningful endpoint. Subsequent studies have questioned the utility of amiodarone in cardiac arrest from the perspective of improving survival to hospital discharge or survival with a good neurological outcome. Read more →
Tag Archive for: Amiodarone
Background: Amiodarone is a class III antidysrhythmic first released for human use in 1962. As with other drugs in this class, amiodarone acts by blocking potassium channels thus prolonging the action potential. This, in turn, leads to a lengthening of depolarization of the atria and ventricles. The drug spread rapidly through US hospitals as it was touted as “always works, and no side effects,” by it’s pharmaceutical manufacturer (Bruen 2016).
Of course, nothing comes free and soon after the drug became widely used, a multitude of adverse effects became apparent. These included minor issues – sun sensitivity and corneal deposits – to major ones – thyroid dysfunction (hypo- and hyperthyroidism), pulmonary toxicity and liver damage. Additionally, the medication’s mechanism of action wasn’t clean and simple – amiodarone is no known to have sodium-channel blocking (Class I), beta-blocking (Class II) and calcium-channel blocking (Class IV) effects.
Despite the multitude of issues, the drug continued to be used extensively because of it’s purported benefits. The drug was most commonly applied in the Emergency Department (ED) for conversion of atrial fibrillation, conversion of stable ventricular tachycardia and in refractory VF/VT cardiac arrest.
This post dives into the three most common places amiodarone is employed in the ED: cardioverion of atrial fibrillation, cardioversion of VT and in refractory VF/VT cardiac arrest and demonstrates that superior evidence points to better options for management. Read more →
REBELCast: The PROCAMIO Trial – IV Procainamide vs IV Amiodarone for the Acute Treatment of Stable Wide Complex Tachycardia
Background: In the ACLS guidelines stable Ventricular Tachycardia (VT) can be treated with either IV amiodarone or IV procainamide, as the drugs of choice. This has been given a class II recommendation, but there has not been a controlled prospective trial to base the use of one drug over the other in the clinical setting. Despite both medications having a class II recommendation, both clinically and anecdotally it appears that amiodarone is the preferred agent in clinical practice. Read more →
Background: Many Out-of-Hospital Cardiac Arrest (OHCA) are attributable to ventricular fibrillation (VF) or pulseless ventricular tachycardia (VT). Both are said to be treatable presentations of OHCA, due to their responsiveness to defibrillation. VF and VT can persist or recur after defibrillation with an inverse relationship between the duration of OHCA, the recurrences of arrhythmias, and ultimately resuscitation outcomes.
Amiodarone and lidocaine are both recommended by the advanced cardiovascular life support (ACLS) guidelines to help promote successful defibrillation in refractory ventricular fibrillation or pulseless ventricular tachycardia and to prevent recurrences. In previous randomized controlled trials patients receiving amiodarone vs placebo or lidocaine in OHCA were more likely to have return of spontaneous circulation (ROSC) and to survive to hospital admission. However the effects of amiodarone on survival to hospital discharge or neurologic outcome still remain uncertain. Should we be using anti-dysrhythmic drugs in out-of-hospital cardiac arrest? Read more →