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University of Michigan Department of Emergency
Originally Published: Modern Resident October/November 2014
Atrial fibrillation (AF) with rapid ventricular response (RVR) is relatively commonplace in the ED, and practice patterns vary in how rate control is achieved. Presented below are different approaches to accomplishing rate control, broken down by medication class and clinical situation.
Big Picture: Calcium Channel Blocker Versus Beta Blocker
The mainstays for rate control agents include calcium channel blockers (CCBs), such as verapamil or diltiazem, or beta blockers (BBs), such as esmolol or metoprolol. Recent literature has trended towards favoring CCB from an overall standpoint, although the difference between the two classes is far from clear-cut.
A recent prospective, randomized, double blind study suggests diltiazem may achieve rate control more rapidly and more effectively than metoprolol. Another earlier study also favors this trend, suggesting diltiazem decreases heart rate by a greater magnitude and more quickly than metoprolol. However, another study suggests esmolol and verapamil both offer adequate rate control, with esmolol more likely to result in cardioversion to normal sinus rhythm.
It is clear that no large-scale, global difference between CCBs and BBs has been identified thus far. Most studies, as referenced above, tend to focus on time to rate control or how well rate is controlled, as opposed to more clinically relevant patient outcomes, such as mortality. In fact, one recent study found no significant difference in admission rate, ED length of stay, adverse events, or ED re-visits between CCBs and BBs used in AF with RVR. From a global standpoint, it appears that both CCBs and BBs are effective for rate control, and specific patient characteristics should guide decisions, as discussed below.
Specific Clinical Conditions
CHF: Both BBs and CCBs should be avoided in decompensated heart failure, as both have negative inotropic effects and can worsen progression of heart failure acutely. Alternatives in this setting include amiodarone and digitalis. However, BBs have long-term mortality benefits in patients with CHF, and thus should be considered prior to CCBs for this patient population.
Pulmonary Disease: BBs should be avoided to prevent worsening bronchospasm, and thus CCBs may be preferred in this setting.
Hypertension: CCBs may be preferred over BBs, as they are considered first line anti-hypertensives.
Hypotension: Electrical cardioversion is preferred. If this proves unsuccessful, phenylepherine can be considered as a temporizing measure. Alternatives include magnesium, amiodarone, and repeating electrical cardioversion.
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