[Efficacy and safety of transthoracic echocardiography-guided percutaneous intramyocardial septal radiofrequency ablation for the treatment of patients with obstructive hypertrophic cardiomyopathy].

Objective

To investigate the safety and efficacy of transthoracic echocardiography-guided percutaneous intramyocardial septal radiofrequency ablation (PIMSRA) in patients with hypertrophic obstructive cardiomyopathy (HOCM).

Methods

Nine HOCM patients with interventricular septal thickness ≥15 mm and ≤25 mm who were treated with PIMSRA between October 2016 to March 2017 in the Hypertrophic Cardiomyopathy Center of Xijing Hospital of Air Force Military Medical University were enrolled,and the clinical data were retrospectively analyzed.Interventricular septum thickness, left ventricular outflow tract diameter and maximum gradient were measured by transthoracic echocardiography immediately after procedure, at 1 month, 3 months and 6 months after operation.Symptoms and New York Heart Association (NYHA) functional class were assessed, and provoked left ventricular outflow tract gradient and exercise time were measured after 6 months.

Results

The anterior interventricular septum ((21.5±2.6) mm vs. (24.7±2.7) mm, P<0.05) and posterior interventricular septum (21.1±2.5) mm vs. (22.6±3.3) mm, P<0.05) were significantly increased,left ventricular outflow tract diameter was widened ((8.2±3.4) mm vs. (4.8±2.2) mm, P<0.05), left ventricular outflow tract gradient ((26.8±19.6) mmHg (1 mmHg=0.133 kPa) vs. (83.3±32.4) mmHg, P<0.05) and mitral regurgitation (2.0±1.9) ml vs. (3.2±3.0) ml, P<0.05) were significantly decreased immediately after ablation compared with pre-operation values. Anterior interventricular septum, posterior interventricular septum and left ventricular outflow tract gradient further decreased after 1 month ((17.5±2.0) mm vs. (24.7±2.7) mm, P<0.05; (16.9±2.1) mm vs. (22.6±3.3) mm, P<0.05; (11.6±4.0) mmHg vs. (26.8±19.6) mmHg, P<0.05, respectively) compared with values immediately after ablation. Anterior interventricular septum and posterior interventricular septum decreased after 3 and 6 months ((14.8±1.7) mm and (13.4±2.0) mm vs. (17.5±2.0) mm, all P<0.05; (12.9±1.9) mm and (12.3±2.4) mm vs. (16.9±2.1) mm, all P<0.05, respectively) compared with values at 1 month after ablation.There were no significantly difference in left ventricular outflow tract gradient at 3 and 6 months post procedure compared with 1 month after ablation (all P>0.05). Compared with pre-operation, provoked left ventricular outflow tract gradient decreased ((25.5±11.4) mmHg vs. (147.8±58.0) mmHg, P<0.01), and total exercise time increased ((9.3±1.6) minutes vs. (6.7±1.6) minutes, P=0.03) at 6 months after operation.The symptoms were disappeared in 5 patients. There were 2 cases with NYHA class Ⅱ and 7 cases with NYHA class Ⅲ before operation,while there were 6 patients with NYHA classⅠ and 3 patients with NYHA class Ⅱ at 6 months after operation (P<0.01).

Conclusion

Transthoracic echocardiography-guided PIMSRA is a safe and effective new treatment approach for patients with obstructive hypertrophic cardiomyopathy.