Safety and efficiency of calcium channel blockers versus beta-blockers for rate control in patients with atrial fibrillation and no acute underlying medical illness

Intravenous diltiazem infusions for rapid atrial fibrillation or flutter in the emergency department: A retrospective, exploratory analysis

BACKGROUND

Emergency physicians commonly treat patients with atrial fibrillation (AF) or atrial flutter (AFL) with rapid ventricular response, and intravenous (IV) diltiazem is the most commonly used medication for rate control of such patients. We sought to compare rate control success and safety outcomes for emergency department (ED) patients with AF or AFL who, after a diltiazem bolus, received a diltiazem drip compared to those who did not receive a drip.

METHODS

We performed a retrospective cohort study comparing outcomes of ED patients from a single hospital system with AF and AFL and a heart rate (HR) > 100 beats/min who received a diltiazem drip after an IV diltiazem bolus to those who received no drip. The primary outcome was a HR < 100 beats/min at the time of ED disposition. Secondary outcomes were hospital length of stay and safety (hypotension, electrical cardioversion, vasopressor use, and death). We compared groups using propensity score matching.

RESULTS

Between January 1, 2020, and November 8, 2022, there were 746 AF or AFL patients eligible for analysis. Of those, 382 (51.2%) received a diltiazem drip and 364 (48.8%) did not. In the unadjusted analysis, the last recorded ED HR was <100 beats/min in 55.2% of patients in the drip group compared to 65.9% in the no-drip group (difference 10.7%, 95% confidence interval [CI] 3.7 to 17.7). After propensity matching, diltiazem drip use was associated with lower likelihood of rate control in the ED (OR 0.69, 95% CI 0.48-0.99) and 22.5 h (95% CI 12.2-36.8) longer hospital stay.

CONCLUSIONS

For patients with AF or AFL, the use of a diltiazem drip after an IV diltiazem bolus was associated with less rate control in the ED.

Atrial fibrillation: better symptom control with rate and rhythm management

Atrial fibrillation (AF) is often associated with limiting symptoms, and with significant impairment in quality of life. As such, treatment strategies aimed at symptom control form an important pillar of AF management. Such treatments include a wide variety of drugs and interventions, including, increasingly, catheter ablation. These strategies can be utilised either singly or in combination, to improve and restore quality of life for patients, and this review covers the current evidence base underpinning their use. In this Review, we discuss the pros and cons of rate vs. rhythm control, while offering practical tips to non-specialists on how to utilise various treatments and counsel patients about all relevant treatment options. These include antiarrhythmic and rate control medications, as well as interventions such as cardioversion, catheter ablation, and pace-and-ablate.

Hypotension and respiratory events related to electrical cardioversion for atrial fibrillation or atrial flutter in the emergency department

INTRODUCTION

Electrical cardioversion for atrial fibrillation/atrial flutter (AF/AFL) is common in the ED. Our previous work showed that hypotension and respiratory events were important adverse events that occurred in patients undergoing electrical cardioversion for AF/AFL. The purpose of this study was to examine if (1) beta-blockers or calcium channel blocker use prior to ECV were associated with hypotension and (2) medications used for procedural sedation were associated with respiratory events.

METHODS

This was a secondary analysis of pooled study data from four previous multicentred studies on AF/AFL. We conducted a multivariable logistic regression to examine predictors of hypotension and respiratory adverse events.

RESULTS

There were 1736 patients who received ECV. A hypotensive event occurred in 62 (3.6%) patients. There was no significant difference in the odds of a hypotensive event in patients who received a beta-blocker or calcium channel blocker in the ED compared to no rate control. Procedural sedation with fentanyl (OR 2.01 95% CI 1.15-3.51) and home beta-blocker use (OR 1.92, 95% CI 1.14-3.21) were significantly associated with hypotensive events. A respiratory event occurred in 179 (10.3%) patients. Older age (OR 2.02, 95% CI 1.30- 3.15) and receiving midazolam for procedural sedation were found to be significantly associated with respiratory events (OR 1.99, 95% CI 1.02-3.88).

CONCLUSION

Beta-blocker or calcium channel blocker use prior to ECV for AF/AFL was not associated with hypotension. However, sedation with fentanyl and home beta-blocker use was associated with hypotension. The use of midazolam for procedural sedation was significantly associated with respiratory events.

2023 ACC/AHA/ACCP/HRS Guideline for the Diagnosis and Management of Atrial Fibrillation: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

The "2023 ACC/AHA/ACCP/HRS Guideline for the Diagnosis and Management of Atrial Fibrillation" provides recommendations to guide clinicians in the treatment of patients with atrial fibrillation.

METHODS

A comprehensive literature search was conducted from May 12, 2022, to November 3, 2022, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, the Agency for Healthcare Research and Quality, and other selected databases relevant to this guideline. Additional relevant studies, published through November 2022, during the guideline writing process, were also considered by the writing committee and added to the evidence tables, where appropriate.

STRUCTURE

Atrial fibrillation is the most sustained common arrhythmia, and its incidence and prevalence are increasing in the United States and globally. Recommendations from the "2014 AHA/ACC/HRS Guideline for the Management of Patients With Atrial Fibrillation" and the "2019 AHA/ACC/HRS Focused Update of the 2014 AHA/ACC/HRS Guideline for the Management of Patients With Atrial Fibrillation" have been updated with new evidence to guide clinicians. In addition, new recommendations addressing atrial fibrillation and thromboembolic risk assessment, anticoagulation, left atrial appendage occlusion, atrial fibrillation catheter or surgical ablation, and risk factor modification and atrial fibrillation prevention have been developed.

2023 ACC/AHA/ACCP/HRS Guideline for the Diagnosis and Management of Atrial Fibrillation: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

The "2023 ACC/AHA/ACCP/HRS Guideline for the Diagnosis and Management of Patients With Atrial Fibrillation" provides recommendations to guide clinicians in the treatment of patients with atrial fibrillation.

METHODS

A comprehensive literature search was conducted from May 12, 2022, to November 3, 2022, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, the Agency for Healthcare Research and Quality, and other selected databases relevant to this guideline. Additional relevant studies, published through November 2022, during the guideline writing process, were also considered by the writing committee and added to the evidence tables, where appropriate.

STRUCTURE

Atrial fibrillation is the most sustained common arrhythmia, and its incidence and prevalence are increasing in the United States and globally. Recommendations from the "2014 AHA/ACC/HRS Guideline for the Management of Patients With Atrial Fibrillation" and the "2019 AHA/ACC/HRS Focused Update of the 2014 AHA/ACC/HRS Guideline for the Management of Patients With Atrial Fibrillation" have been updated with new evidence to guide clinicians. In addition, new recommendations addressing atrial fibrillation and thromboembolic risk assessment, anticoagulation, left atrial appendage occlusion, atrial fibrillation catheter or surgical ablation, and risk factor modification and atrial fibrillation prevention have been developed.

An Updated Review on the Role of Non-dihydropyridine Calcium Channel Blockers and Beta-blockers in Atrial Fibrillation and Acute Decompensated Heart Failure: Evidence and Gaps

PURPOSE

The 2021 European Society of Cardiology guidelines on acute and chronic heart failure (HF) recommend that non-dihydropyridine calcium channel blockers (NDCC) should be avoided in patients with HF with reduced ejection fraction. It also emphasizes that beta-blockers only be initiated in clinically stable, euvolemic patients. Despite these recommendations, NDCC and beta-blockers are often still employed in patients with AF with rapid ventricular response and acute decompensated HF. The relative safety and efficacy of these therapies in this setting is unclear.

METHODS

To address the question of the safety and efficacy of NDCC and beta-blockers for acute rate control in decompensated HF, we provide a perspective on the literature of NDCC and beta-blockers in chronic HF with reduced and preserved ejection fraction and AF, including trials on the management of AF with rapid ventricular response with and without HF.

RESULTS

Robust data demonstrates mortality benefits when beta-blockers are used in patients with chronic HF with reduced ejection fraction. The data that inform the contraindication of NDCC in HF with reduced ejection fraction are outdated and were not primarily designed to address the efficacy and safety of rate control of AF in patients with HF. Several studies indicate that for acute rate control, NDCC and beta-blockers are both efficacious therapies, especially in the setting of tachycardia-induced cardiomyopathy.

CONCLUSION

Future studies are needed to assess the safety and efficacy of beta-blockers and NDCC in both acute and chronic AF with HF with reduced and preserved ejection fraction.

Development of a Care Pathway for Atrial Fibrillation Patients in the Emergency Department

Atrial fibrillation (AF) is the most common cardiac arrhythmia and its prevalence is continuously increasing in the United States, leading to a progressive rise in the number of disease-related emergency department (ED) visits and hospitalizations. Although optimal long-term outpatient management for AF is well defined, the guidelines for optimal ED management of acute AF episodes is less clear. Studies have demonstrated that discharging patients with AF from the ED after acute stabilization is both safe and cost effective; however, the majority of these patients in the United States and in our institution are admitted to the hospital. To improve care of these patients, we established a multidisciplinary collaboration to develop an evidence-based systematic approach for the treatment and management of AF in the ED, that led to the creation of the University of California-Cardioversion, Anticoagulation, Rate Control, Expedited Follow-up/Education Atrial Fibrillation Pathway. Our pathway focuses on the acute stabilization of AF, adherence to best practices for anticoagulation, and reduction in unnecessary admissions through discharge from the ED with expedited outpatient follow-up whenever safe. A novel aspect of our pathway is that it is primarily driven by the ED physicians, while other published protocols primarily involve consulting cardiologists to guide management in the ED. Our protocol is very pertinent considering the current trend toward increased AF prevalence in the United States, coupled with a need for widespread implementation of strategies aimed at improving management of these patients while safely reducing hospital admissions and the economic burden of AF.

Rapid Atrial Fibrillation in the Emergency Department

Atrial fibrillation (AF) is the most common rhythm disorder seen in doctors' offices and emergency departments (EDs). In both settings, an AF holistic pathway including anticoagulation or stroke avoidance, better symptom management, and cardiovascular and comorbidity optimization should be followed. However, other considerations need to be assessed in the ED, such as haemodynamic instability, the onset of AF, the presence of acute heart failure and pre-excitation. Although the Advanced Cardiovascular Life Support guidelines (European Society of Cardiology guidelines, Acute Cardiac Care Association/European Heart Rhythm Association position statements) and several recent AF publications have greatly assisted physicians in treating AF with rapid ventricular response in the ED, further practical clinical guidance is required to improve physicians' skill and knowledge in providing the best treatment for patients. Herein, we combine multiple strategies with supporting evidence-based treatment and experiences encountered in clinical practice into practical stepwise approaches. We hope that the stepwise algorithm may assist residents and physicians in managing AF in the ED.

Analysis of the ESC/EACTS 2020 Atrial Fibrillation Guidelines With Perioperative Implications

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia worldwide, with an individual lifetime risk of approximately 37% in the United States. Broadly defined as a supraventricular tachyarrhythmia with disorganized atrial activation, AF results in an increased risk of stroke, heart failure, valvular heart disease, and impaired quality of life, and confers a significant burden on the health of individuals and society. AF in the perioperative setting is common and a significant source of perioperative morbidity and mortality worldwide. The latest iteration of the European Society of Cardiology AF guidelines published in 2020 provide the clinician a valuable road map for the management of this arrythmia. This expert review will comprehensively analyze the 2020 European Society of Cardiology guidelines and provide perioperative management tools for the clinician.

Guidelines for enhanced recovery after cardiac surgery. Consensus document of Spanish Societies of Anesthesia (SEDAR), Cardiovascular Surgery (SECCE) and Perfusionists (AEP)

The ERAS guidelines are intended to identify, disseminate and promote the implementation of the best, scientific evidence-based actions to decrease variability in clinical practice. The implementation of these practices in the global clinical process will promote better outcomes and the shortening of hospital and critical care unit stays, thereby resulting in a reduction in costs and in greater efficiency. After completing a systematic review at each of the points of the perioperative process in cardiac surgery, recommendations have been developed based on the best scientific evidence currently available with the consensus of the scientific societies involved.

Comparison of sustained rate control in atrial fibrillation with rapid ventricular rate: Metoprolol vs. Diltiazem

OBJECTIVE

The objective of this study was to compare sustained rate control with intravenous (IV) diltiazem vs. IV metoprolol in acute treatment of atrial fibrillation (AF) with rapid ventricular rate (RVR) in the emergency department (ED).

METHODS

This retrospective chart review at a large, academic medical center identified patients with AF with RVR diagnosis who received IV diltiazem or IV metoprolol in the ED. The primary outcome was sustained rate control defined as heart rate (HR) < 100 beats per minute without need for rescue IV medication for 3 h following initial rate control attainment. Secondary outcomes included time to initial rate control, HR at initial control and 3 h, time to oral dose, admission rates, and safety outcomes.

RESULTS

Between January 1, 2016 and November 1, 2018, 51 patients met inclusion criteria (diltiazem n = 32, metoprolol n = 19). No difference in sustained rate control was found (diltiazem 87.5% vs. metoprolol 78.9%, p = 0.45). Time to rate control was significantly shorter with diltiazem compared to metoprolol (15 min vs. 30 min, respectively, p = 0.04). Neither hypotension nor bradycardia were significantly different between groups.

CONCLUSIONS

Choice of rate control agent for acute management of AF with RVR did not significantly influence sustained rate control success. Safety outcomes did not differ between treatment groups.

Evaluation of the blood pressure effects of diltiazem versus metoprolol in the acute treatment of atrial fibrillation with rapid ventricular rate

PURPOSE

To evaluate the difference in blood pressure effects of diltiazem intravenous push (IVP) and metoprolol IVP in the acute management of atrial fibrillation with rapid ventricular rate (AF with RVR).

METHODS

This was a single-center, retrospective cohort study evaluating patients who presented to the emergency department (ED) between January 2012 and September 2018 in AF with RVR and received either diltiazem IVP or metoprolol IVP as the first agent for rate control. The primary objective was the change in systolic blood pressure (SBP) within one hour of initial medication administration. Secondary outcomes included repeat doses within one hour, rate control to <110 beats per minute, and SBP <90 mmHg or decrease by >40% within three hours. Subgroup analysis of patients with a baseline SBP <110 mmHg was conducted.

RESULTS

Of the 160 patients included, 80 received diltiazem and 80 metoprolol. The primary outcome of median change in SBP at one hour was a difference of -9 [-21 to 6] mmHg in the diltiazem group versus a difference of -4 [-18 to 9] mmHg in the metoprolol group (p = 0.102). Subgroup analysis (n = 28) of patients with a baseline SBP <110 mmHg demonstrated an increase of 7 [-0.25 to 19] mmHg in the diltiazem group versus increase of 7 [0 to 13] in the metoprolol group (p = 0.910).

CONCLUSION

No significant difference was observed in the blood pressure effects of diltiazem IVP versus metoprolol IVP in the acute management of AF with RVR.

The 2020 Canadian Cardiovascular Society/Canadian Heart Rhythm Society Comprehensive Guidelines for the Management of Atrial Fibrillation

The Canadian Cardiovascular Society (CCS) atrial fibrillation (AF) guidelines program was developed to aid clinicians in the management of these complex patients, as well as to provide direction to policy makers and health care systems regarding related issues. The most recent comprehensive CCS AF guidelines update was published in 2010. Since then, periodic updates were published dealing with rapidly changing areas. However, since 2010 a large number of developments had accumulated in a wide range of areas, motivating the committee to complete a thorough guideline review. The 2020 iteration of the CCS AF guidelines represents a comprehensive renewal that integrates, updates, and replaces the past decade of guidelines, recommendations, and practical tips. It is intended to be used by practicing clinicians across all disciplines who care for patients with AF. The Grading of Recommendations, Assessment, Development and Evaluations (GRADE) system was used to evaluate recommendation strength and the quality of evidence. Areas of focus include: AF classification and definitions, epidemiology, pathophysiology, clinical evaluation, screening and opportunistic AF detection, detection and management of modifiable risk factors, integrated approach to AF management, stroke prevention, arrhythmia management, sex differences, and AF in special populations. Extensive use is made of tables and figures to synthesize important material and present key concepts. This document should be an important aid for knowledge translation and a tool to help improve clinical management of this important and challenging arrhythmia.

Rate Control Management of Atrial Fibrillation With Rapid Ventricular Response in the Emergency Department

BACKGROUND

There exists limited evidence on managing atrial fibrillation (AF) with rapid ventricular response in the emergency department. We sought to better understand the burden of disease in patients with AF for whom rhythm control was not successful or not attempted and identify opportunities for improved care.

METHODS

We conducted a health records review of consecutive visits of patients with AF at 2 academic emergency departments. We included patients ≥ 18 years with AF, heart rate ≥ 100 beats per minute (bpm), and who were not successfully cardioverted or not attempted cardioversion. Outcomes were: (1) incidence given rate control, (2) management practices, (3) adverse events, (4) compliance with guidelines, and (5) outcomes. We performed descriptive statistics.

RESULTS

We included 665 visits, with mean age ± standard deviation 77.4 ± 12.9, female 51.6%, mean ± standard deviation heart rate 121.6 ± 17.4 bpm, AF status (permanent 53.4%; paroxysmal 29.5%; persistent 17.1%), admitted 61.4%. Of all cases, 147 (22.1%) had primary AF and 518 (77.9%) had a rapid rate secondary to a medical cause (heart failure 12.8%; pneumonia 11.7%; sepsis 8.4%). In 117 with primary AF given rate control, 59.0% had a final rate ≤ 100 bpm and 7.7% suffered adverse events. Suboptimal use of rate control occurred in 47.0% (agent 2.6%; route 27.4%; dosage 9.4%; timing 7.7%). At discharge, 11.5% with CHADS-65 risk factors were still not anticoagulated.

CONCLUSIONS

Most patients had a rapid rhythm secondary to a medical cause. There were a concerning number of adverse events related to suboptimal use of rate control. Better awareness of guidelines will ensure safer use of rate control.

Active management of atrial fibrillation or flutter in emergency department patients with renal impairment is associated with a higher risk of adverse events and treatment failure

Objective

Atrial fibrillation or flutter (AFF) patients with renal impairment have poor long-term prognosis, but their emergency department (ED) management has not been described. We investigated the association of renal impairment upon outcomes after rate or rhythm control (RRC) including ED-based adverse events (AE) and treatment failure.

Methods

This cohort study used an electrocardiogram database from two urban centres to identify consecutive AFF patients and reviewed charts to obtain comorbidities, ED management, including RRC, prespecified AE, and treatment failure. Patients were dichotomized into a normal estimated glomerular filtration rate (eGFR) > 60 mL/min/1.73 m2) or impaired renal function (“low eGFR”). Primary and secondary outcomes were prespecified AEs and treatment failure, respectively. We calculated 1) adjusted excess AE risk for patients with decreased renal function receiving RRC; and 2) adjusted odds ratio of RRC treatment failure.

Results

Of 1,112 consecutive ED AFF patients, 412 (37.0%) had a low eGFR. Crude AE rates for RRC were 27/238 (11.3%) for patients with normal renal function and 26/103 (25.2%) for patients with low eGFR. For patients with low eGFR receiving RRC, adjusted excess AE risk was 13.7%. (95% CI 1.7 to 25.1%). For patients with low eGFR, adjusted odds ratio for RRC failure was 3.07. (95% CI 1.74 to 5.43)

Conclusions

In this cohort of ED AFF patients receiving RRC, those with low eGFR had significantly increased adjusted excess risk of AE compared with patients with normal renal function. Odds of treatment failure were also significantly increased.

Dysrhythmias and heart failure complicating acute myocardial infarction: An emergency medicine review

INTRODUCTION

Patients with acute myocardial infarction (AMI) may suffer several complications after the acute event, including dysrhythmias and heart failure (HF). These complications place patients at risk for morbidity and mortality.

OBJECTIVE

This narrative review evaluates literature and guideline recommendations relevant to the acute emergency department (ED) management of AMI complicated by dysrhythmia or HF, with a focus on evidence-based considerations for ED interventions.

DISCUSSION

Limited evidence exists for ED management of dysrhythmias in AMI due to relatively low prevalence and frequent exclusion of patients with active cardiac ischemia from clinical studies. Management decisions for bradycardia in the setting of AMI are determined by location of infarction, timing of the dysrhythmia, rhythm assessment, and hemodynamic status of the patient. Atrial fibrillation is common in the setting of AMI, and caution is warranted in acute rate control for rapid ventricular rate given the possibility of compensation for decreased ventricular function. Regular wide complex tachycardia in the setting of AMI should be managed as ventricular tachycardia with electrocardioversion in the majority of cases. Management directed towards HF from left ventricular dysfunction in AMI consists of noninvasive positive pressure ventilation, nitroglycerin therapy, and early cardiac catheterization. Norepinephrine is the first line vasopressor for patients with cardiogenic shock and hypoperfusion on clinical examination. Early involvement of a multi-disciplinary team is recommended when caring for patients in cardiogenic shock.

CONCLUSIONS

This review discusses considerations of ED management of dysrhythmias and HF associated with AMI.

Frequency of "on-label" use of intravenous diltiazem for rate control in patients with acute-onset atrial fibrillation or atrial flutter

Purpose

The study was designed to characterize "on-label" use of i.v. diltiazem in patients with acute atrial fibrillation or flutter (AFF).

Methods

An IRB-approved, single-center, retrospective, observational design was used. Eligible patients had acute AFF with heart rate >120 bpm and received i.v. diltiazem from June 1, 2012, to June 30, 2014. The primary outcome was frequency of on-label use of i.v. diltiazem, defined as use of at least one FDA-approved weight-based bolus dose followed by an infusion, if appropriate, in the absence of contraindications.

Results

A total of 300 patients were screened; 97 patients were included for analysis. I.V. diltiazem was used on-label in only 14 patients (14%). Of the 96 patients who received an initial diltiazem bolus injection, the median dose was significantly higher in patients for whom the diltiazem dose was on-label, as follows: 17.5 mg (interquartile range [IQR]), 10-20 mg vs. 10.0 mg (IQR, 10-20 mg), p < 0.02). Twenty-nine patients (35%) in the off-label group had a therapeutic response to diltiazem alone compared with 8 patients (57%) in the on-label group (p = 0.11). More patients treated with off-label diltiazem bolus injection required additional rate control medications (41% vs. 7%, p < 0.04).

Conclusion

In most patients, i.v. diltiazem was not used in accordance with FDA labeling. For most, i.v. diltiazem doses were lower than recommended and many of these patients required additional rate control medications to achieve a therapeutic response.

2018 Korean Guideline of Atrial Fibrillation Management

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia in the general population. The Korean Heart Rhythm Society organized a Korean AF Management Guideline Committee and analyzed all available studies regarding the management of AF, including studies on Korean patients. This guideline is based on recent data of the Korean population and the recent guidelines of the European Society of Cardiology, European Association for Cardio-Thoracic Surgery, American Heart Association, and Asia Pacific Heart Rhythm Society. Expert consensus or guidelines for the optimal management of Korean patients with AF were achieved after a systematic review with intensive discussion. This article provides general principles for appropriate risk stratification and selection of anticoagulation therapy in Korean patients with AF. This guideline deals with optimal stroke prevention, screening, rate and rhythm control, risk factor management, and integrated management of AF.

Management and Disposition of Atrial Fibrillation in the Emergency Department: A Systematic Review

Introduction

Management of atrial fibrillation (AF) and atrial flutter (AFL) in the emergency department (ED) varies greatly, and there are currently no United States guidelines to guide management with regard to patient disposition after ED treatment. The aim of this systematic review was to evaluate the literature for decision aids to guide disposition of patients with AF/AFLin the ED, and assess potential outcomes associated with different management strategies in the ED.

Methods and Results

A systematic review was done using PubMed (MEDLINE), Cochrane Central Register of Controlled Trials (CENTRAL), and EMBASE, combining the search terms "Atrial Fibrillation", "Atrial Flutter", "Emergency Medicine", "Emergency Service", and "Emergency Treatment". After removal of duplicates, 754 articles were identified. After initial screening of titles and abstracts, 69full text articles were carefully reviewed and 34 articles were ultimately included in the study based on inclusion and exclusion criteria. The articles were grouped into four main categories: decision aids and outcome predictors, electrical cardioversion-based protocols, antiarrhythmic-based protocols, and general management protocols.

Conclusion

This systematic review is the first study to our knowledge to evaluate the optimal management of symptomatic AF/AFLin the ED with a direct impact on ED disposition. There are several viable management strategies that can result in safe discharge from the ED in the right patient population, and decision aids can be utilized to guide selection of appropriate patients for discharge.

Rate Control With Beta-blockers Versus Calcium Channel Blockers in the Emergency Setting: Predictors of Medication Class Choice and Associated Hospitalization

OBJECTIVES

Rate control is an important component of the management of patients with atrial fibrillation (AF). Previous studies of emergency department (ED) rate control have been limited by relatively small sample sizes. We examined the use of beta-blockers (BBs) versus nondihydropyridine calcium channel blockers (CCBs) in ED patients from 24 sites and the associated hospital admission rates.

METHODS

In this preplanned substudy, we examined chart data on AF patients who visited one of 24 hospital EDs in Ontario, Canada, between April 2008 and March 2009. We describe the proportion of patients who received either a BB or a CCB, had a heart rate < 110 beats/min 2 hours later, and had any complications. We used hierarchical logistic regression modeling to determine the predictors of BB versus CCB use and to assess the between-hospital variation in use of BBs versus CCBs. Solely in patients who had no rhythm control attempts, we examined the difference in the probability of hospital admission after propensity score matching patients by medication class.

RESULTS

Of the 1,639 patients who received either a BB (n = 429) or a CCB (n = 1,210), 70.9% of the patients who received a BB had successful rate control versus 66.1% for a CCB. Complications were rare (2.4%), and the large majority were hypotension (2.0%). In adjusted analyses, predictors of receiving a BB (compared to a CCB) included already being on a BB, being sent in from a doctor's office, or being seen at a teaching hospital. In contrast, patients with evidence of heart failure, prior use of a CCB, a higher presenting heart rate, or a successful pharmacologic cardioversion (vs. no attempt) or who were seen at the highest AF volume EDs were significantly less likely to receive a BB, compared to a CCB. Systematic between-hospital differences accounted for 8% of the variation in BB versus CCB use. Hospital characteristics accounted for the large majority of that variation: after accounting for patient characteristics the between-hospital variation decreased by a relative 2.8%. By further adjusting for hospital characteristics, it decreased by a relative 74.7%. Among propensity score-matched patients with no rhythm control attempts, more CCB patients were admitted (51.6%) compared to BB patients (40.0%; difference of 11.6%; 95% confidence interval = 7.9%-16.2%).

CONCLUSIONS

In this study of 24 EDs, CCBs were used more frequently for rate control than BBs, and complications were rare and easily managed using both agents. Variation between hospitals in BB versus CCB use was predominantly due to hospital characteristics such as teaching status and AF volumes, rather than different case mix. Among patients who did not receive attempts at rhythm control, use of a BB for rate control was associated with a lower rate of hospitalization.

Diltiazem vs. Metoprolol in the Management of Atrial Fibrillation or Flutter with Rapid Ventricular Rate in the Emergency Department

BACKGROUND

Diltiazem (calcium channel blocker) and metoprolol (beta-blocker) are both commonly used to treat atrial fibrillation/flutter (AFF) in the emergency department (ED). However, there is considerable regional variability in emergency physician practice patterns and debate among physicians as to which agent is more effective. To date, only one small prospective, randomized trial has compared the effectiveness of diltiazem and metoprolol for rate control of AFF in the ED and concluded no difference in effectiveness between the two agents.

OBJECTIVE

Our aim was to compare the effectiveness of diltiazem with metoprolol for rate control of AFF in the ED.

METHODS

A convenience sample of adult patients presenting with rapid atrial fibrillation or flutter was randomly assigned to receive either diltiazem or metoprolol. The study team monitored each subject's systolic and diastolic blood pressures and heart rates for 30 min.

RESULTS

In the first 5 min, 50.0% of the diltiazem group and 10.7% of the metoprolol group reached the target heart rate (HR) of <100 beats per minute (bpm) (p < 0.005). By 30 min, 95.8% of the diltiazem group and 46.4% of the metoprolol group reached the target HR < 100 bpm (p < 0.0001). Mean decrease in HR for the diltiazem group was more rapid and substantial than that of the metoprolol group. From a safety perspective, there was no difference between the groups with respect to hypotension (systolic blood pressure < 90 mm Hg) and bradycardia (HR < 60 bpm).

CONCLUSIONS

Diltiazem was more effective in achieving rate control in ED patients with AFF and did so with no increased incidence of adverse effects.

Noradrenaline transmission reducing drugs may protect against a broad range of diseases

1 A growing body of evidence suggests that the signalling molecule, noradrenaline (NA), plays a pathophysiological role in a broad range of psychiatric, neurological and peripheral disorders. Both preclinical and clinical data suggest that elevated NA signalling may be involved in the aetiology of major diseases such as depression, Alzheimer's disease and diabetes mellitus. 2 The molecular pathways by which NA may cause the manifestation of disease remain poorly understood, although they may include G protein-coupled receptor modulation of the Ras/MAP kinase, Stat3 and PI3K pathways, among others. In both individual animals and humans, NA tone may be elevated largely due to genetics, but also because of the exposure to marked psychological stress or trauma, or other environmental factors. 3 As NA is involved in the 'fight or flight' response by the sympathetic nervous system, this transmitter may be elevated in a large number of organisms due to evolutionary selection of enhancing responses to immediate environmental dangers. Likewise, acetylcholine signalling by the parasympathetic ('rest and digest') nervous system may be relatively diminished. This putative autonomic imbalance may result in diminished engagement in homeostatic processes, resulting in the emergence and progression of a number of diseases throughout the body. 4 In this scenario, a large number of individuals may benefit from chronic use of pharmacological agents - such as clonidine, guanfacine, propranolol or prazosin - that diminish NA signalling throughout the body. If so, NA transmission lowering drugs may protect against a wide range of diseases.

Selective β1-Antagonism with Bisoprolol Is Associated with Fewer Postoperative Strokes than Atenolol or Metoprolol

Background:

Perioperative metoprolol increases postoperative stroke. Animal studies indicate that the mechanism may be related to attenuated β2-adrenoreceptor-mediated cerebral vasodilatation. The authors therefore conducted a cohort to study whether the highly β1-specific β-blocker (bisoprolol) was associated with a reduced risk of postoperative stroke compared with less selective β-blockers (metoprolol or atenolol).

Methods:

The authors conducted a single-center study on 44,092 consecutive patients with age 50 yr or more having noncardiac, nonneurologic surgery. The primary outcome was stroke within 7 days of surgery. The secondary outcome was a composite of all-cause mortality, postoperative myocardial injury, and stroke. A propensity score-matched cohort was created to assess the independent association between bisoprolol and less β1-selective agents metoprolol or atenolol. A secondary analysis using logistic regression, based on previously identified confounders, also compared selective β1-antagonism.

Results:

Twenty-four percent (10,756) of patients were exposed to in-hospital β-blockers. A total of 88 patients (0.2%) suffered a stroke within 7 days of surgery. The matched cohort consisted of 2,462 patients, and the pairs were well matched for all variables. Bisoprolol was associated with fewer postoperative strokes than the less selective agents (odds ratio = 0.20; 95% CI, 0.04–0.91). Multivariable risk-adjustment in the β-blockers-exposed patients comparing bisoprolol with the less selective agents was associated with a similarly reduced stroke rate.

Conclusions:

The use of metoprolol and atenolol is associated with increased risks of postoperative stroke, compared with bisoprolol. These findings warrant confirmation in a pragmatic randomized trial.