What are the indications for atrial fibrillation (AF) ablation in patients with Hypertrophic Cardiomyopathy (HCM)?

Indications for Atrial Fibrillation Ablation in Patients with HCM

Catheter ablation for AF should be performed in HCM patients with symptomatic AF when drug therapy is ineffective, contraindicated, or not the patient's preference as part of a rhythm control strategy. 1

Primary Indications for Catheter Ablation

The 2020 AHA/ACC HCM Guidelines provide a Class 2a recommendation (Level B-NR) for catheter ablation in HCM patients with symptomatic AF as part of a rhythm control strategy when antiarrhythmic drugs fail or are not tolerated. 1

Specific Clinical Scenarios:

• Symptomatic AF refractory to pharmacological control - This is the primary indication, with catheter ablation considered reasonable when patients remain symptomatic despite adequate trials of antiarrhythmic medications 1

• Poorly tolerated AF - HCM patients often experience significant hemodynamic compromise with AF due to their dependence on atrial contraction for ventricular filling, making rhythm control particularly important 1

• Drug intolerance or contraindications - When antiarrhythmic medications cause unacceptable side effects or cannot be used due to contraindications, ablation becomes a reasonable alternative 1

• Patient preference - After appropriate counseling about risks and benefits, patient preference for ablation over long-term drug therapy is a valid indication 1

Surgical AF Ablation Indications

Concomitant surgical AF ablation can be beneficial for AF rhythm control in HCM patients who require surgical myectomy. 1

Specific surgical scenarios:

• Patients undergoing septal myectomy - When HCM patients with AF are already undergoing open heart surgery for LVOT obstruction, adding surgical AF ablation (particularly the maze procedure) is reasonable 1

• Stand-alone surgical ablation - May be considered in highly symptomatic patients with refractory AF, though data is limited 1

Important Clinical Context and Expectations

Success Rates and Realistic Expectations:

• Single-procedure success is modest - Only 45.5% of HCM patients remain free from atrial arrhythmias after a single ablation procedure, significantly lower than the general AF population 2

• Multiple procedures often required - With repeat procedures, success rates improve to 66.1% overall, with better outcomes in paroxysmal AF (71.8%) compared to persistent AF (47.5%) 2, 3

• Long-term outcomes - At 6-year follow-up, approximately 53% of patients remain free from AF recurrence after multiple procedures, with most requiring continuation of antiarrhythmic drugs 3

Factors Predicting Lower Success:

• Persistent or permanent AF (versus paroxysmal) has significantly worse outcomes 4, 2

• Severe left atrial enlargement (LA volume index >70 mL/m²) predicts higher recurrence rates 4

• Advanced diastolic dysfunction correlates with worse ablation outcomes 4

• Marked atrial enlargement and severe diastolic dysfunction identify high-risk patients for recurrence 1

Clinical Benefits Beyond Rhythm Control

Successful ablation improves functional status and quality of life in HCM patients. 4, 3

• Patients maintaining sinus rhythm after ablation demonstrate better NYHA functional class (1.6 vs 2.0, p=0.009) compared to those with recurrent AF 3

• Quality of life scores show significant improvement at 3 and 12 months post-ablation 4

Safety Considerations

The complication rate is acceptable but requires careful patient counseling. 2

• Serious periprocedural complications occur in approximately 5.1% of cases 2

• Reported complications include transient ischemic attacks, pulmonary vein stenosis, and rare catastrophic events 4

• The risk-benefit ratio must be carefully discussed with each patient before proceeding 1

Critical Contraindications

Catheter ablation should NOT be performed in patients who cannot receive anticoagulation therapy during and after the procedure. 1

Ablation should NOT be performed solely to eliminate the need for anticoagulation - all HCM patients with AF require lifelong anticoagulation regardless of CHA₂DS₂-VASc score or ablation success 1

Algorithmic Approach to Decision-Making

1. Confirm symptomatic AF causing significant quality of life impairment despite rate control 1

2. Trial appropriate antiarrhythmic drugs (amiodarone or disopyramide plus beta-blocker as first-line) 1

3. If drug therapy fails, is not tolerated, or patient prefers ablation → proceed with catheter ablation 1

4. If patient requires septal myectomy → strongly consider concomitant surgical AF ablation 1

5. Set realistic expectations - inform patients that multiple procedures are often needed and antiarrhythmic drugs may still be required 2, 3

6. Ensure lifelong anticoagulation regardless of ablation outcome 1