In patients with hypertrophic cardiomyopathy (HCM), atrial fibrillation (AF) is the most common clinical complication. The occurrence of AF is associated with deterioration of functional capacity, quality of life, and long-term outcome. Therefore, maintenance of sinus rhythm is highly desirable. Donna et al., therefore did a study to analyze the long-term results of RFCA in patients with HCM and AF.

The study group included 61 patients with HCM and AF from Italy and France. The radiofrequency catheter ablation (RFCA) protocol involved pulmonary vein (PV) isolation, roof line, mitral annulus line and cavotricuspid isthmus line. A 1-month blanking period was considered for all patients following catheter ablation. Following the blanking period, a repeat ablation procedure was undertaken in the event of a recurrence of AF or atrial tachycardia. Patients were followed at 1, 3, 6, and 12 months and every 6 months thereafter. Antiarrhythmic therapy was discontinued after 3 months unless there was evidence of recurrent non-sustained ventricular tachycardia. The study endpoint was recurrence of AF, atrial tachycardia, or atrial flutter lasting more than 3 min.

Mean age of the 61 study patients was 54 years. 72% were men. All patients were in sinus rhythm at the end of the first RFCA. No major periprocedural complications occurred. Of the 61 patients, 17 (28%) remained in sinus rhythm after a single procedure. Conversely, 44 (72%) had AF recurrences within 14 months from the first procedure. In 12 patients, a rate control approach was chosen. In the remaining 32 patients, a redo procedure was performed. Total duration of follow-up was 40 months. 3 patients died during follow up due to causes unrelated to RFCA. At the time of final evaluation, 41 patients (67%) were in stable sinus rhythm, and therefore considered as RFCA successes. Conversely, the remaining 20 patients (33%) were considered as RFCA failures due to AF recurrence. The overall RFCA success rate at 1, 2, and 3 years was 95, 83, and 71%, respectively. All patients with successful RFCA had marked improvement in functional status. The 20 patients that were considered to be RFCA failures still showed significant improvement in NYHA functional class. At the time of final evaluation, 46% of patients with successful RFCA were in sinus rhythm without antiarrhythmic treatment.

RFCA success rates were higher among patients who were younger, had smaller LA size, better functional status, and without long-standing persistent AF at the time of the procedure. In a multivariate Cox regression model, the only independent predictors of AF recurrence were LA volume and NYHA functional class. Of note, LA volume >150 mL was associated with an almost four-fold independent increase in the likelihood of RFCA failure during follow-up.

Conclusion: The present study showed that RFCA was successful in restoring long-term sinus rhythm and improving symptomatic status in most HCM patients with refractory AF. Younger HCM patients with small atrial size, mild symptoms, and shorter duration of AF proved to be the best candidates for RFCA of AF. The study highlights the importance of patient selection to improve outcomes of RFCA of AF.

Reference:

Di Donna P, Olivotto I, Delcrè SD, Caponi D, Scaglione M, Nault I, Montefusco A, Girolami F, Cecchi F, Haissaguerre M, Gaita F. Efficacy of catheter ablation for atrial fibrillation in hypertrophic  cardiomyopathy: impact of age, atrial remodelling, and disease progression. Europace. 2010 Mar;12(3):347-55.