From the Guidelines
For a patient in atrial flutter requiring rapid response, immediate management should focus on stabilizing the patient and controlling the heart rate with intravenous rate-controlling medications such as metoprolol or diltiazem, as recommended by the 2015 ACC/AHA/HRS guideline for the management of adult patients with supraventricular tachycardia 1. The initial approach should involve assessing the patient's hemodynamic stability and controlling the ventricular rate to prevent complications such as heart failure or myocardial ischemia.
- Key considerations include:
- Administering intravenous metoprolol 5mg IV (can repeat up to 3 doses) or diltiazem 0.25 mg/kg IV over 2 minutes (can repeat with 0.35 mg/kg after 15 minutes if needed) for rate control, as supported by the guideline 1.
- Proceeding with synchronized cardioversion at 50-100 joules if the patient is hemodynamically unstable with hypotension, altered mental status, or signs of shock, in line with the recommendations for acute treatment of atrial flutter 1.
- Obtaining a 12-lead ECG to confirm atrial flutter, typically showing a characteristic "saw-tooth" pattern with regular atrial activity at 250-350 beats per minute and variable ventricular response.
- Checking electrolytes, particularly potassium and magnesium, and correcting any abnormalities to prevent potential complications. Once the patient is stabilized, consideration should be given to anticoagulation based on the CHA₂DS₂-VASc score if the duration of atrial flutter is unknown or greater than 48 hours, as recommended for patients with atrial flutter to align with antithrombotic therapy for patients with AF 1. For long-term management, options include:
- Rhythm control with antiarrhythmic medications (such as amiodarone, flecainide, or propafenone), as suggested by the guideline for maintaining sinus rhythm in patients with symptomatic recurrent atrial flutter 1.
- Rate control with beta-blockers or calcium channel blockers.
- Catheter ablation for recurrent episodes, which may be considered for patients with CTI-dependent atrial flutter or those undergoing catheter ablation of AF who also have a history of documented clinical or induced CTI-dependent atrial flutter 1.
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. A defibrillator and emergency equipment should be readily available 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.
Diltiazem (IV) is indicated for temporary control of rapid ventricular rate in atrial flutter.
- The initial step in management should include vagal maneuvers unless contraindicated.
- Administration of diltiazem hydrochloride injection should be done with continuous monitoring of the ECG and frequent measurement of blood pressure.
- A defibrillator and emergency equipment should be readily available.
- Diltiazem hydrochloride injection can be effective in reducing heart rate by at least 20% in 95% of patients with atrial flutter 2.
From the Research
Rapid Response Patient in Atrial Flutter Workup
- Atrial flutter is a cardiac rhythm disturbance that arises in the upper chambers of the heart, and it can be treated with medical intervention strategies such as electrical cardioversion, pharmacological therapy, and catheter ablation 3.
- For acute rate control of atrial fibrillation/flutter and rapid ventricular response, intravenous diltiazem and metoprolol are commonly used, with studies suggesting that diltiazem may be more effective in achieving rate control 4, 5, 6.
- A meta-analysis of randomized and observational studies found that intravenous diltiazem was more effective than intravenous metoprolol for heart rate control in randomized trials, but not in observational studies 4.
- Another study found that diltiazem was more effective in achieving rate control in emergency department patients with atrial fibrillation/flutter, with no increased incidence of adverse effects 5.
- Radiofrequency catheter ablation has emerged as a safe and effective first-line treatment for typical atrial flutter, due to its well-defined anatomic and electrophysiological substrate 7.
- A meta-analysis of 17 studies found that intravenous diltiazem had higher efficacy, shorter average onset time, lower ventricular rate, and less impact on blood pressure compared to intravenous metoprolol, with no significant difference in adverse events 6.
Treatment Options
- Electrical cardioversion: a procedure that uses electrical shocks to restore a normal heart rhythm 3.
- Pharmacological therapy: medications such as diltiazem and metoprolol can be used to control heart rate and rhythm 4, 5, 6.
- Catheter ablation: a minimally invasive procedure that uses radiofrequency energy to destroy the abnormal electrical pathways in the heart 3, 7.
Key Findings
- Diltiazem may be more effective than metoprolol for acute rate control of atrial fibrillation/flutter and rapid ventricular response 4, 5, 6.
- Radiofrequency catheter ablation is a safe and effective first-line treatment for typical atrial flutter 7.
- Intravenous diltiazem has higher efficacy, shorter average onset time, and lower ventricular rate compared to intravenous metoprolol, with no significant difference in adverse events 6.