How do we treat atrial arrhythmias?

Treatment of Atrial Arrhythmias

The treatment of atrial fibrillation should follow a dual approach focusing on stroke prevention with anticoagulation and symptom management through either rate or rhythm control strategies, with selection based on patient characteristics and comorbidities. 1

Anticoagulation Therapy

• Administer antithrombotic therapy to all patients with AF except those with lone AF to prevent thromboembolism 2
• Use the CHA₂DS₂-VA score for stroke risk assessment, with anticoagulation therapy considered for scores ≥1 and strongly recommended for scores ≥2 1
• For high-risk patients, provide chronic oral anticoagulation with warfarin adjusted to achieve a target INR of 2.0-3.0 2
• Direct oral anticoagulants (DOACs) are preferred over vitamin K antagonists like warfarin for most patients 1
• Continue anticoagulation based on stroke risk even after successful rhythm control 1
• Monitor INR at least weekly during initiation of warfarin therapy and monthly when stable 2

Rate Control Strategy

First-line medications:

• For patients with preserved left ventricular ejection fraction (LVEF >40%):

  • Beta-blockers (e.g., metoprolol, atenolol)
  • Non-dihydropyridine calcium channel blockers (diltiazem, verapamil)
  • Digoxin (less effective as monotherapy) 2, 1

• For patients with reduced LVEF (≤40%):

  • Beta-blockers and/or digoxin are recommended 1
  • Avoid non-dihydropyridine calcium channel blockers due to negative inotropic effects 2

• Consider combination therapy with digoxin plus beta-blocker or calcium channel antagonist to control heart rate at rest and during exercise 2

Special situations:

• For AF with WPW syndrome: Avoid beta-blockers, digoxin, diltiazem, and verapamil as they may accelerate ventricular response 2
• For AF with thyrotoxicosis: Use beta-blockers as first-line therapy; if contraindicated, use calcium channel antagonists 2

Rhythm Control Strategy

Indications:

• Symptomatic patients despite adequate rate control
• Younger patients, especially with paroxysmal lone AF
• Patients with AF secondary to a corrected precipitant 2, 3

Cardioversion options:

• Immediate electrical cardioversion for:

  • Hemodynamic instability
  • Acute myocardial infarction with rapid ventricular response
  • Symptomatic hypotension
  • Angina or cardiac failure unresponsive to medications 2

• Pharmacological cardioversion with:

  • Flecainide, propafenone (for patients without structural heart disease)
  • Amiodarone (safe in patients with structural heart disease)
  • Ibutilide 1, 4

Maintenance of sinus rhythm:

• Amiodarone is more effective than sotalol and propafenone for maintaining sinus rhythm but has more adverse effects 3
• Class IC antiarrhythmic drugs (flecainide, propafenone) are preferred in structurally normal hearts 4
• Avoid Class IC drugs in patients with coronary artery disease or structural heart disease 4

Catheter Ablation

• Consider catheter ablation as a second-line option if antiarrhythmic drugs fail to control AF 1
• May be considered as first-line therapy in selected patients with paroxysmal AF 1
• Particularly beneficial for symptomatic patients with AF involving accessory pathways (WPW syndrome) 2

Common Pitfalls and Caveats

• Do not use digitalis as the sole agent to control rapid ventricular response in paroxysmal AF 2
• Do not discontinue anticoagulation after successful rhythm control if the patient has risk factors for stroke 1
• Do not reduce DOAC doses unless patients meet specific dose-reduction criteria 1
• Avoid class IC antiarrhythmic drugs in patients with acute myocardial infarction 2
• Rate control strategy may be preferable to rhythm control in older patients (>65 years) and those with coronary heart disease due to fewer adverse events 3, 5

Treatment Algorithm

1. Assess stroke risk and initiate appropriate anticoagulation
2. Determine whether rate or rhythm control is appropriate:
   • For older patients, those with comorbidities, or minimally symptomatic AF: Rate control
   • For younger patients, highly symptomatic patients, or those with new-onset AF: Consider rhythm control
3. If rate control chosen:
   • Select appropriate medication based on LVEF and comorbidities
   • Target heart rate <110 bpm at rest
4. If rhythm control chosen:
   • Consider cardioversion (electrical or pharmacological)
   • Select appropriate antiarrhythmic drug based on cardiac structure
   • Consider catheter ablation if drug therapy fails