The use of diltiazem for treating rapid atrial fibrillation in the out-of-hospital setting

Prehospital Treatment of Atrial Fibrillation: Infusion Pump for Bolus and Infusion?

OBJECTIVE

The prehospital treatment for stable patients with atrial fibrillation with rapid ventricular response is rate-controlling agents such as calcium channel blockers, often diltiazem given as a bolus. At our agency we encourage the use of a bolus given via the infusion pump over two to four minutes immediately followed by a maintenance infusion, given concerns of recurrent tachycardia or hypotension secondary to rapid bolus administration. We examined if administering a bolus and infusion via an infusion pump shows better heart rate (HR) control at arrival to the emergency department (ED) compared with administration of a bolus only, while maintaining hemodynamic stability during transport. We also analyzed if a patient received a second bolus within 60 min of arrival to the ED.

METHODS

We used a retrospective propensity-matched cohort of prehospital patients with atrial fibrillation for whom diltiazem was administered, from 1/1/2018 to 12/31/2021, in our system of 10 New Jersey paramedic units. We analyzed the age, gender, and initial HR and used it to match groups. We analyzed the mode and time of administration, dosage of the bolus, and presence of hypotension prehospitally.

RESULTS

The matched groups contained 145 patients who received a prehospital diltiazem bolus only (BO) and 146 patients who received a diltiazem bolus and infusion (BI). There was no significant difference between the mean change in HR from initial paramedic arrival to ED arrival between the two groups (BO 38 vs. BI 34, p = 0.16). There was no significant difference in the need for a second bolus within the first 60 min of arrival to the ED (BO 9.7% vs. BI 11.6%, p = 0.30). Patients in the BO group were more likely to experience prehospital hypotension then in the BI group (BO 17.2% vs BI 8.2%, p = 0.01), despite receiving smaller initial bolus doses (BO 14.2 mg vs. BI 17.4 mg, p < 0.001).

CONCLUSION

Our results show no significant differences in HR control or need for repeat bolus at the ED with the use of a diltiazem infusion following a diltiazem bolus. However, even when administering larger boluses, the use of an infusion pump resulted in less hypotension.

Efficacy and Safety of Prehospital Diltiazem

OBJECTIVE

This study assesses the likelihood of clinical improvement and adverse events from EMS-administered diltiazem. Current prehospital protocols direct paramedics to administer diltiazem, a calcium channel blocker, to decrease the heart rate (HR) of symptomatic, hemodynamically stable patients with rapid atrial fibrillation. However, diltiazem can also cause systemic hypotension and bradycardia, which can precipitate end-organ injury. .

METHODS

To assess whether the rate control benefit of prehospital diltiazem outweighs the risk of adverse events, we conducted a retrospective chart review of all adult patients who received diltiazem from Maryland Advanced Life Support EMS clinicians between January 1, 2019, and March 31, 2022. Collected data included patient demographics, vital signs, diltiazem dose, transport times, administered medications, and procedures. The main outcomes were clinical improvement (HR <100 beats per minute or ≥20% decrease from the maximum HR) and adverse events (bradycardia or hypotension). Multivariable logistic regression was used for statistical analysis.

RESULTS

During the study period, 2396 patients received prehospital diltiazem and 94% of these patients (n = 2254) were included in the study. Overall, 1414 (63.8%) patients improved clinically, 604 (27.3%) patients achieved rate control as defined by a HR of <100 beats per minute, and 78 patients (3.5%) experienced an adverse event. Patients over the age of 50 were less likely to clinically improve with diltiazem administration. Adverse events were more likely in patients with systolic blood pressures (SBP) less than 140 mmHg, patients with maximum HR of less than 120 beats per minute, and patients who received nitroglycerin.

CONCLUSIONS

Prehospital diltiazem is effective and safe for most patients. Adverse events are more likely in patients with baseline SBP less than 140 mmHg, HR less than 120 beats per minute, and concurrent nitroglycerin administration. Future opportunities for research include examining the relationship between adverse events and underlying etiology as well as investigating downstream outcomes.

Prehospital Intervention Improves Outcomes for Patients Presenting in Atrial Fibrillation with Rapid Ventricular Response

OBJECTIVE

To compare outcomes of patients presenting to emergency medical services (EMS) with atrial fibrillation with rapid ventricular response (AF-RVR) who did and did not receive prehospital advanced life support (ALS) rate or rhythm control intervention(s).

METHODS

This retrospective cohort study used the 2021 ESO Data Collaborative (Austin, TX) dataset. We identified 9-1-1 scene responses for patients aged 16 to 100 years old presenting with AF and an initial heart rate ≥ 110 beats per minute (bpm). Prehospital ALS interventions for AF-RVR included medications (e.g., calcium channel blockers, beta blockers, etc.) or electrical cardioversion. Outcome measures included prehospital rate control (i.e., final prehospital heart rate < 110 bpm), emergency department (ED) discharge to home, ED and hospital length of stay, and mortality. We also evaluated prehospital adverse events-specifically bradycardia, hypotension, and cardiac arrest. We used propensity score matching to compare outcomes among treated and untreated patients with similar demographic and clinical characteristics. We determined the average treatment effect on the treated (ATET) with 95% confidence intervals (CI) and the number needed to treat (NNT).

RESULTS

After propensity score matching, prehospital outcomes were available for 4,859 treated patients matched with 4,859 similar untreated patients. Prehospital rate control was more frequent for treated than for untreated patients (41.0% vs. 18.2%, ATET +22.8%, CI: +21.1%; +24.6%, NNT = 5). Hospital outcomes were available for 1,347 treated patients matched with 1,347 similar untreated patients. Treated patients were more likely to be discharged from the ED (37.9% vs. 34.0%, ATET +3.9%, CI: +0.2%; +7.5%, NNT = 26) and less likely to die (4.3% vs. 6.7%, ATET -2.5%, CI: -4.2%; -0.8%, NNT = 40) compared to untreated patients. Hypotension occurred more often in treated patients (ATET +2.6%, CI: +1.5%; +3.7%), but resolved before ED arrival in 73% of affected patients. Otherwise, adverse event rates did not significantly differ for the two groups.

CONCLUSIONS

In this propensity score matched study of patients presenting to EMS with AF-RVR, prehospital ALS interventions were associated with more frequent prehospital rate control, more frequent discharge to home from the ED, and lower mortality.

Safety and Efficacy of Prehospital Diltiazem for Atrial Fibrillation with Rapid Ventricular Response

INTRODUCTION

Atrial fibrillation (AFIB) with rapid ventricular response (RVR) is a common tachydysrhythmia encountered by Emergency Medical Services (EMS). Current guidelines suggest rate control in stable, symptomatic patients.

PROBLEM

Little is known about the safety or efficacy of rate-controlling medications given by prehospital providers. This study assessed a protocol for prehospital administration of diltiazem in the setting of AFIB with RVR for provider protocol compliance, patient clinical improvement, and associated adverse events.

METHODS

This was a retrospective, cohort study of patients who were administered diltiazem by providers in the Orange County EMS System (Florida USA) over a two-year period. The protocol directed a 0.25mg/kg dose of diltiazem (maximum of 20mg) for stable, symptomatic patients in AFIB with RVR at a rate of &gt;150 beats per minute (bpm) with a narrow complex. Data collected included patient characteristics, vital signs, electrocardiogram (ECG) rhythm before and after diltiazem, and need for rescue or additional medications. Adverse events were defined as systolic blood pressure &lt;90mmHg or administration of intravenous fluid after diltiazem administration. Clinical improvement was defined as a heart rate decreased by 20% or less than 100bmp. Original prehospital ECG rhythm interpretations were compared to physician interpretations performed retrospectively.

RESULTS

Over the study period, 197 patients received diltiazem, with 131 adhering to the protocol. The initial rhythm was AFIB with RVR in 93% of the patients (five percent atrial flutter, two percent supraventricular tachycardia, and one percent sinus tachycardia). The agreement between prehospital and physician rhythm interpretation was 92%, with a Kappa value of 0.454 (P &lt;.001). Overall, there were 22 (11%) adverse events, and 112 (57%) patients showed clinical improvement. When diltiazem was given outside of the existing protocol, the patients had higher rates of adverse events (18% versus eight percent; P = .033). Patients who received diltiazem in adherence with protocols were more likely to show clinical improvement (63% versus 46%; P = .031).

CONCLUSION

This study suggests that prehospital diltiazem administration for AFIB with RVR is safe and effective when strict protocols are followed.Rodriguez A, Hunter CL, Premuroso C, Silvestri S, Stone A, Miller S, Zuver C, Papa L. Safety and efficacy of prehospital diltiazem for atrial fibrillation with rapid ventricular response. Prehosp Disaster Med. 2019;34(3):297-302.

Safety and efficacy of prehospital diltiazem

Introduction: Very few studies exist on the use of diltiazem in the prehospital setting. Some practitioners believe this medication is prone to causing hypotension in this setting. Our goals were to determine whether the prehospital administration of diltiazem induced hypotension and to evaluate the efficacy of the drug.

Methods: Our two-tiered system is located in a suburban region of New Jersey with advanced life support (ALS) care provided by fly-car units. The ALS units do not transport patients, and all of them are hospital based. The ALS providers are employed by the hospital system. In New Jersey, all ALS care requires online medical control, including the administration of diltiazem. We retrospectively reviewed patient care records for those who were believed to be in rapid atrial fibrillation and were given diltiazem in a suburban emergeny medical services system over a 22-month period. We examined the differences between heart rate (HR) and blood pressure (BP) on the initial evaluation and on arrival to the emergency department (ED). A hypotensive response was defined as a final systolic BP (SBP) less than 90 mmHg and a drop in SBP of at least 10 mmHg. Diltiazem was considered effective if the ED HR was <100 beats per minute (bpm) or if it decreased ≥20%.

Results: During the study period, 26,979 patients were transported. Of these patients, 2,488 had a documented rhythm of atrial fibrillation or atrial flutter. Of the 320 patients who received diltiazem, 42 patient encounters were excluded for incomplete data, yielding 278 patients for analysis. The average initial SBP was 139 mmHg and the average diastolic BP was 84 mmHg. The average diltiazem dosage was 16.7 mg. Two patients became hypotensive. The average initial HR was 154 bpm. On arrival to the ED, 33% of the patients had an HR < 100 bpm and 69% had a drop in HR ≥ 20%. The overall efficacy of prehospital diltiazem was 73%.

Conclusion: In the prehospital setting, diltiazem is associated with a very low rate of hypotension and appears to be effective in decreasing HR adequately. Prospective studies are needed to confirm these findings.

Acute management of atrial fibrillation

Acute atrial fibrillation (AF) is the most common cardiac rhythm encountered in clinical practice and is commonly seen in acutely ill patients in critical care. In the latter setting, AF may have two main clinical sequelae: (1) haemodynamic instability and (2) thromboembolism. The approach to the management of AF can broadly be divided into a rate control strategy or a rhythm control strategy, and is largely driven by symptom assessment and functional status. A crucial part of AF management requires the appropriate use of thromboprophylaxis. In patients who are haemodynamically unstable with AF, urgent direct current cardioversion should be considered. Apart from electrical cardioversion, drugs are commonly used, and Class I (flecainide, propafenone) and Class III (amiodarone) antiarrhythmic drugs are more likely to revert AF to sinus rhythm. Beta blockers and rate limiting calcium blockers, as well as digoxin, are often used in controlling heart rate in patients with acute onset AF. The aim of this review article is to provide an overview of the management of AF in the critical care setting.

Tratamiento de la fibrilación auricular en los distintos niveles asistenciales de un área sanitaria

BACKGROUND AND OBJECTIVE

Atrial fibrillation is managed in multiple settings by different specialists. We sought to analyze treatment and compliance of the prevailing guidelines of patients with atrial fibrillation attended at different levels of health care and to quantify interventions to correct treatment inadequacies.

PATIENTS AND METHOD

We included all adult patients with atrial fibrillation who presented during a 14 day-period to different levels of health care of a tertiary hospital and a related primary care clinic (family physician, cardiologist, emergency department, hospitalization). In all of them, clinical and epidemiological data in relation to atrial fibrillation, and all data referring to treatment and compliance of guidelines, were recorded prospectively.

RESULTS

293 patients were included. Clinical and epidemiological data were similar in the different settings. A great diversity in atrial fibrillation treatment was observed. In 30 and 33% of the patients, antiarrhythmic and antithrombotic treatment, respectively, did not meet the recommendations of the prevailing guidelines. The adequacy was inferior in primary care. The adequacy percentages increased slightly after the medical attention (2 and 3% respectively, p non significant) with no differences in this increase between the different settings.

CONCLUSIONS

There are no epidemiological differences between patients with atrial fibrillation treated at different levels of health care. An important number of patients do not follow the recommendations of the prevailing guidelines. There is a clear medical abstention in incorrectly treated cases.

Comparison of the effectiveness of intravenous diltiazem and metoprolol in the management of rapid ventricular rate in atrial fibrillation

OBJECTIVE

To compare the effectiveness of intravenous (IV) diltiazem and metoprolol in the management of rapid ventricular rate in atrial fibrillation (AF).

METHODS

This prospective, randomised study was conducted in the Emergency Department of the Uludag University Medical Faculty Hospital, Bursa, Turkey. Forty AF patients with a ventricular rate > or = 120/minute and systolic blood pressure > or = 95 mm Hg were included and randomised to receive IV diltiazem 0.25 mg/kg (maximum 25 mg) or metoprolol 0.15 mg/kg (maximum 10 mg) over 2 minutes. Blood pressures and heart rate were measured at 2, 5, 10, 15, and 20 minutes. Successful treatment was defined as fall in ventricular rate to below 100/minute or decrease in ventricular rate by 20% or return to sinus rhythm.

RESULTS

Between January 2000 and July 2002, 40 patients (18 men, 22 women) met the inclusion criteria. Of these 20 (8 men, 12 women; mean age 60.2 years, range 31-82) received diltiazem and 20 (10 men, 10 women; mean age 64.0 years, range 31-82) received metoprolol. The success rate at 20 minutes for diltiazem and metoprolol was 90% (n = 18) and 80% (n = 16), respectively. The success rate at 2 minutes was higher in the diltiazem group. The percentage decrease in ventricular rate was higher in the diltiazem group at each time interval. None of the patients had hypotension.

CONCLUSION

Both diltiazem and metoprolol were safe and effective for the management of rapid ventricular rate in AF. However, the rate control effect began earlier and the percentage decrease in ventricular rate was higher with diltiazem than with metoprolol.

Comparison of the effectiveness of intravenous diltiazem and metoprolol in the management of rapid ventricular rate in atrial fibrillation

OBJECTIVE

To compare the effectiveness of intravenous (IV) diltiazem and metoprolol in the management of rapid ventricular rate in atrial fibrillation (AF).

METHODS

This prospective, randomised study was conducted in the Emergency Department of the Uludag University Medical Faculty Hospital, Bursa, Turkey. Forty AF patients with a ventricular rate > or = 120/minute and systolic blood pressure > or = 95 mm Hg were included and randomised to receive IV diltiazem 0.25 mg/kg (maximum 25 mg) or metoprolol 0.15 mg/kg (maximum 10 mg) over 2 minutes. Blood pressures and heart rate were measured at 2, 5, 10, 15, and 20 minutes. Successful treatment was defined as fall in ventricular rate to below 100/minute or decrease in ventricular rate by 20% or return to sinus rhythm.

RESULTS

Between January 2000 and July 2002, 40 patients (18 men, 22 women) met the inclusion criteria. Of these 20 (8 men, 12 women; mean age 60.2 years, range 31-82) received diltiazem and 20 (10 men, 10 women; mean age 64.0 years, range 31-82) received metoprolol. The success rate at 20 minutes for diltiazem and metoprolol was 90% (n = 18) and 80% (n = 16), respectively. The success rate at 2 minutes was higher in the diltiazem group. The percentage decrease in ventricular rate was higher in the diltiazem group at each time interval. None of the patients had hypotension.

CONCLUSION

Both diltiazem and metoprolol were safe and effective for the management of rapid ventricular rate in AF. However, the rate control effect began earlier and the percentage decrease in ventricular rate was higher with diltiazem than with metoprolol.

Prehospital management of acute tachyarrhythmias

Arrhythmias are commonly encountered by emergency medical services (EMS) personnel. The potential seriousness of acute symptomatic arrhythmias necessitates thorough up-to-date training of EMS personnel. The three most common acute tachyarrhythmias, not linked to cardiac arrest, that are observed outside the hospital are paroxysmal supraventricular tachycardia (PSVT), atrial fibrillation with rapid ventricular response (RAF), and perfusing ventricular tachycardia (VT). Ideally, these tachyarrhythmias should be operationally defined in a manner that simplifies, particularly for EMS providers, their diagnosis and treatment. The authors recommend referring to these rhythms as regular narrow-complex tachycardia (presumed PSVT), irregularly irregular narrow-complex tachycardia (presumed RAF), or regular wide-complex tachycardia (presumed VT or aberrantly conducted PSVT). Although the value of treatments such as cardioversion is widely understood, the benefit from others, such as lidocaine, is unclear. Current preferences, recommendations, and concerns regarding the treatment of most arrhythmias outside the hospital reflect the dichotomy that sometimes exists between available evidence and actual practice.