Radiofrequency septal ablation as a therapeutic option in refractory obstructive hypertrophic cardiomyopathy to myectomy: a case series

Abstract Introduction Hypertrophic cardiomyopathy (HCM) presents as obstructive in 76% of cases, when the peak left ventricular outflow tract gradient (LVOTG) exceeds 30 mmHg. In severe cases with LVOTG 50 mmHg, associated with refractory symptoms, myectomy is indicated as the invasive therapy of choice. However, some patients remain symptomatic with significant residual LVOTG despite surgical septal reduction. We describe a case series where radiofrequency septal ablation (RFSA) was performed in this patient population. Objective To assess whether RFSA is a safe and effective treatment for patients with obstructive HCM refractory to myectomy. Methods Retrospective, observational, single-centre study based on a case series. Statistical analysis was conducted to evaluate the efficacy of LVOTG reduction between myectomy and RFSA using the paired t-test, with p 0.05 considered significant. Results Six patients with obstructive HCM were included, four adults (one male) and two children (one male), all of whom had previously undergone septal myectomy. The mean age was 40 ± 24.5 years, with resting/provoked LVOTG of 118 ± 24 mmHg, and all patients were classified as functional class (FC) III. Due to refractory symptoms, with five patients remaining in FC III and one in FC IV, and persistent LVOTG (LVOTG = 103 ± 32 mmHg despite a reduction of 16 ± 26.7 mmHg), all patients underwent RFSA after a mean period of 61.1 ± 56 months following myectomy (mean age of 46 ± 25.4 years). A significant improvement in LVOTG (LVOTG = 34 ± 32.8 mmHg) was observed, with a reduction of 68 ± 32 mmHg, and only one patient had LVOTG 30 mmHg, demonstrating the superiority of RFSA over myectomy in these cases (t(5) = -3.09; p 0.05). There was an improvement in FC in all patients, with four remaining in FC I and two in FC II, without postoperative complications. Discussion and Conclusion: In patients with obstructive HCM, myectomy, the gold standard invasive treatment, may yield unsatisfactory results in fewer than 10% of cases, particularly in those with elevated LVOTG and persistent limiting symptoms. Re-surgical approaches carry high operative risks, while medical treatment with mavacamten, although effective, remains less accessible. RFSA has proven to be an effective and safe treatment in this patient cohort, as evidenced by a significant reduction in LVOTG, which translated into a substantial clinical improvement. A limitation of the analysis is the probable change in the site of obstruction between myectomy and RFSA.