GME Patient Safety Quality and Innovation Symposium

Background

Atrial fibrillation (AF) is a common arrhythmia with two general treatment approaches: rate or rhythm control. Rate control in AF is achieved by decreasing AV nodal conduction velocity with beta blockade or calcium channel inhibition. Based on the result of the AFFIRM trial, beta blockers (BBs) were more commonly used, and a higher percentage of the patients achieved adequate heart rate (HR) control (< 110 bpm) compared to calcium channel blockers (CCBs). In addition to the choice of medication, the dosing strategy of diltiazem is explored. Guidelines The 2014 AHA/ACC/HRS Guideline for the Management of Patients with Atrial Fibrillation recommend 0.25 mg/kg IV bolus. An additional bolus of 0.35 mg/kg can be given if no therapeutic response within 15 minutes.  Which body weight to use (actual vs. ideal) is not specified by the guidelines but actual body weight (ABW) is commonly used. However, in an obese patient, the use of ABW may lead to more side effects as the dose is larger.  Our project aims to evaluate the use and dosing of BBs and CCBs in the Emergency Department (ED) of Jacobs Medical Center (JMC) for patients presenting in atrial fibrillation with rapid ventricular response (AF-RVR). 

Methods

This retrospective chart review included adult patients who presented to the ED of JMC in AF-RVR and who received rate-controlling drugs between 01/01/2021 to 09/01/2022. The primary objective was the percentage of patients who achieved adequate rate control (HR < 110 bpm) within the first 90 minutes after drug administration. The secondary objectives included the prevalence of bradycardia (HR < 60 bpm) or hypotension (SBP < 90 mmHg) within 90 minutes of drug administration. Lastly, the decrease in HR was evaluated by drug, route, and weight-normalized dose. 

Results

In the predefined time frame, 241 patients were identified with 126 meeting inclusion criteria. The main reason for exclusion was HR < 110 bpm prior to drug administration. Sixty percent of the study population was male with a mean age of 69 years and weight of 82.2 kg. The most prevalent comorbidities were hypertension (54%) and heart failure (38.9%). Sixty-one percent of patients had atrial fibrillation listed in their medical history. More studied patients (39.7%) were on BBs prior to admission than CCBs (5.6%).

More patients (71%) received BBs than CCBs (23%). Many (45.8%) achieved the primary objective. Of those, more (77%) received BBs than CCBs (15%). Few experienced hypotension (6.8%) or bradycardia (2%). Failure to achieve HR rate less than 110 bpm was 50% for BBs and 71.9% for CCBs. The average dose of IV diltiazem per weight was only 0.15 mg/kg.

Conclusion

BBs were used more frequently at the JMC ED for patients who presented in AF-RVR. A higher percentage of failure to achieve target HR goal was seen with CCBs, however, the CCBs were suboptimally dosed when normalized by body weight. This study highlights the importance of appropriate CCBs dosing when treating patients presenting to the ED in AF-RVR.

Figures/Tables

My abstract includes tables of figures that will be displayed on the poster.