Early hemodynamic response and safety after PIMSRA or surgical myectomy for obstructive hypertrophic cardiomyopathy: a real-world cohort study

Percutaneous intramyocardial septal radiofrequency ablation is an emerging septal reduction strategy for obstructive hypertrophic cardiomyopathy, but comparative routine-care data remain limited. We evaluated early hemodynamic response, functional improvement, and procedure-specific safety after radiofrequency ablation or surgical myectomy in a real-world cohort. We studied 130 consecutive adults with obstructive hypertrophic cardiomyopathy managed from 2020 to 2024 at a tertiary referral center: radiofrequency ablation (47 patients), modified transaortic septal myectomy (42 patients), or conservative therapy (41 patients). The main efficacy focus was 3- and 6-month resting left ventricular outflow tract peak-gradient response among interventional patients. A gradient of 10 mmHg or less was applied post hoc as a stringent exploratory responder definition, and a gradient below 30 mmHg was a secondary threshold. Available-case analysis of covariance and exploratory overlap weighting were used as supportive analyses; a tiered composite captured durable procedure-specific safety events. Groups were clinically imbalanced. New York Heart Association class III-IV symptoms were present in 35/46 ablation patients (76.1%), 37/42 surgical patients (88.1%), and 18/41 conservatively managed patients (43.9%). At 3 months, a gradient of 10 mmHg or less was observed in 7/32 ablation patients (21.9%) and 17/33 surgical patients (51.5%; absolute risk difference, + 29.6% points; 95% confidence interval, + 6.1 to + 50.2; p = 0.020). A gradient below 30 mmHg was observed in 14/32 (43.8%) and 26/33 (78.8%; p = 0.005), respectively. Analysis of covariance showed lower adjusted residual gradients after surgery at 3 months (geometric mean ratio, 0.264; p = 0.0003) and 6 months (0.318; p = 0.002). At 3 months, improvement by at least one New York Heart Association class occurred in 25/45 ablation patients and 28/39 surgical patients. The hard safety composite occurred in 4/47 ablation patients and 4/42 surgical patients. Surgical myectomy was associated with more complete early gradient relief, whereas radiofrequency ablation was associated with observed hemodynamic and functional improvement in this routine-care cohort. Baseline imbalance, incomplete follow-up, and nonrandomized treatment allocation preclude causal comparative claims, and this study did not identify patient-selection criteria.