Treatment of Atrial Flutter with Variable AV Block
Beta blockers, diltiazem, or verapamil are the first-line treatments for atrial flutter with variable AV block in hemodynamically stable patients. 1
Acute Management
Hemodynamically Stable Patients
- Intravenous or oral beta blockers (metoprolol, atenolol, esmolol) are effective for acute rate control in patients with atrial flutter who are hemodynamically stable 1
- Non-dihydropyridine calcium channel blockers (diltiazem, verapamil) are equally effective alternatives for acute rate control 1, 2
- Intravenous diltiazem is often the preferred calcium channel blocker for acute rate control due to its safety and efficacy profile 1
- The goal of treatment should be to achieve a resting heart rate of less than 100 beats per minute 3
- Combination therapy may be necessary as rate control can be more difficult to achieve in atrial flutter than in atrial fibrillation 1, 4
Hemodynamically Unstable Patients
- Synchronized cardioversion is recommended for acute treatment of patients with atrial flutter who are hemodynamically unstable 1
- For patients with hemodynamic collapse or congestive heart failure, emergent DC-synchronized shock is indicated 1
- Atrial flutter can often be successfully converted with lower energy levels than those required for atrial fibrillation 1
Pharmacological Cardioversion Options
- Oral dofetilide or intravenous ibutilide can be useful for acute pharmacological cardioversion in patients with atrial flutter 1
- Ibutilide converts atrial flutter to sinus rhythm in approximately 60% of cases, but carries risk of torsades de pointes 1
- Pretreatment with magnesium can increase efficacy and reduce the risk of torsades de pointes when using ibutilide 1
Special Considerations
Wolff-Parkinson-White Syndrome
- Beta blockers, digoxin, adenosine, and non-dihydropyridine calcium channel blockers are contraindicated in patients with Wolff-Parkinson-White syndrome 1, 2
- These medications can facilitate antegrade conduction along the accessory pathway, potentially resulting in acceleration of the ventricular rate, hypotension, or ventricular fibrillation 1, 4
- For hemodynamically stable patients with pre-excitation, type I antiarrhythmic agents or amiodarone may be administered intravenously 1, 2
Patients with Heart Failure
- Beta blockers are generally preferred in patients with heart failure 1, 2
- Non-dihydropyridine calcium channel blockers (diltiazem, verapamil) should be avoided in patients with advanced heart failure 1, 2
- Amiodarone may be considered for rate control when conventional measures are ineffective, though it is typically reserved for situations where other options are limited 1
Patients with COPD
- Non-dihydropyridine calcium channel blockers are preferred in patients with bronchial asthma and chronic obstructive pulmonary disease 2, 4
- Selective beta-1 blockers (such as bisoprolol) at low doses may be considered in patients with COPD 2
Long-Term Management
Pharmacological Therapy
- Long-term rate control can be achieved with oral beta blockers, diltiazem, or verapamil 1, 3
- Digoxin is not recommended as monotherapy for rate control in active patients but may be used in combination with other agents 3
- For rhythm control, options include sotalol, amiodarone, dofetilide, propafenone, and flecainide, though these carry potential for proarrhythmia and side effects 5, 6
- When using class Ic agents like propafenone, concomitant AV nodal blocking drugs should be administered to prevent 1:1 AV conduction during atrial flutter 1, 7
Catheter Ablation
- Catheter ablation of the cavotricuspid isthmus (CTI) is useful in patients with atrial flutter that is either symptomatic or refractory to pharmacological rate control 1
- CTI ablation has a success rate of over 90% for typical atrial flutter 5, 6
- For non-CTI-dependent flutter, catheter ablation is useful in patients with recurrent symptomatic flutter after failure of at least one antiarrhythmic agent 1
Anticoagulation
- Antithrombotic therapy is recommended according to the same risk profile used for atrial fibrillation 1
- For atrial flutter lasting more than 48 hours or of unknown duration, anticoagulation is recommended for at least 3 weeks before and 4 weeks after cardioversion 2
Causes of Atrial Flutter with Variable AV Block
- Digitalis toxicity is a common cause of atrial tachycardia with AV block 1
- Other causes include structural heart disease, atrial enlargement, and congenital heart disease 1
- Certain medications can induce variable AV block in patients with atrial flutter
- Underlying sinus node dysfunction may contribute to the development of variable AV block 1