From the Guidelines
For managing atrial fibrillation with rapid ventricular response (AFib with RVR) using IV diltiazem, start with a loading dose of 0.25 mg/kg (typically 15-20 mg) administered over 2 minutes, as recommended by the 2010 American Heart Association guidelines for cardiopulmonary resuscitation and emergency cardiovascular care 1. This approach is supported by the guidelines, which suggest that IV diltiazem is a drug of choice for acute rate control in most individuals with atrial fibrillation and rapid ventricular response. The dose and administration are also consistent with the recommendations outlined in the 2001 ACC/AHA/ESC guidelines for the management of patients with atrial fibrillation 1, which provides a table of intravenous pharmacological agents for heart rate control in patients with atrial fibrillation. However, it's essential to consider the potential risks and contraindications, such as heart failure with reduced ejection fraction, hypotension, or concomitant use of beta-blockers, as noted in the 2014 AHA/ACC/HRS guideline for the management of patients with atrial fibrillation 1. Some key points to consider when using IV diltiazem for AFib with RVR management include:
- Assessing the heart rate response after 15 minutes and giving a second bolus if inadequate rate control persists
- Initiating a continuous infusion at 5-15 mg/hour to maintain a heart rate below 100-110 beats per minute
- Monitoring blood pressure closely during administration due to the risk of hypotension
- Checking cardiac enzymes and obtaining an echocardiogram to rule out structural heart disease
- Avoiding diltiazem in patients with certain conditions, such as heart failure with reduced ejection fraction or hypotension, and considering alternative agents like beta-blockers or amiodarone in these situations. Overall, the use of IV diltiazem for AFib with RVR management should be guided by the most recent and highest-quality evidence, with careful consideration of the potential benefits and risks in each individual patient.
From the FDA Drug Label
Diltiazem Hydrochloride Injection or Diltiazem Hydrochloride for Injection are indicated for the following: Atrial Fibrillation or Atrial Flutter Temporary control of rapid ventricular rate in atrial fibrillation or atrial flutter Unless otherwise contraindicated, appropriate vagal maneuvers should be attempted prior to administration of diltiazem hydrochloride injection For either indication and particularly when employing continuous intravenous infusion, the setting should include continuous monitoring of the ECG and frequent measurement of blood pressure. In domestic controlled trials in patients with atrial fibrillation or atrial flutter, bolus administration of diltiazem hydrochloride injection was effective in reducing heart rate by at least 20% in 95% of patients.
Management of Afib with RVR using IV Diltiazem:
- IV Diltiazem is indicated for temporary control of rapid ventricular rate in atrial fibrillation or atrial flutter.
- The drug can be effective in reducing heart rate by at least 20% in 95% of patients.
- Key considerations:
- Vagal maneuvers should be attempted prior to administration of IV Diltiazem.
- Continuous monitoring of ECG and frequent measurement of blood pressure are necessary.
- The setting should have a defibrillator and emergency equipment readily available 2.
From the Research
Afib with RVR Management with IV Diltiazem
- IV diltiazem is effective in controlling the ventricular rate in acute atrial fibrillation (AF) with rapid ventricular response (RVR) 3, 4, 5
- The addition of digoxin to the regimen may cause a favorable outcome, but digoxin as a single agent is generally inefficacious in slowing the ventricular rate in acute AF 3
- IV diltiazem can be used in the prehospital setting for AF with RVR, with a protocol-directed dose of 0.25mg/kg (maximum of 20mg) showing safety and efficacy 4
- In hemodynamically stable patients, rate control using beta blockers or calcium channel blockers, such as diltiazem, should be pursued 6, 5
- Diltiazem likely achieves rate control faster than metoprolol, though both agents seem safe and effective 5
- However, in patients with congestive heart failure with reduced ejection fraction (HFrEF), IV diltiazem may have a higher incidence of worsening heart failure symptoms compared to metoprolol 7
Key Considerations
- Differentiating primary and secondary AF with RVR and evaluating hemodynamic stability are vital components of ED assessment and management 6
- Troponin can assist in determining the risk of adverse outcomes, but universal troponin testing is not required in patients at low risk of acute coronary syndrome or coronary artery disease 6
- Anticoagulation is an important component of management, and several tools (e.g., CHA2DS2-VASc) are available to assist with this decision 6
- Disposition can be challenging, and several risk assessment tools (e.g., RED-AF, AFFORD, and the AFTER scores) are available to assist with disposition decisions 6