P4588Echo guided septal radiofrequency ablation for treatment of obstructive hypertrophic cardiomiopathy - Case series

Abstract

Hipertrophic cardiomiopathy affects one in every 500 person. Two thirds of those present LV outflow tract gradient, often symptomatic and requiring medical treatment. Patients refractory to medical treatment require myectomy or alcohol septal ablation. Recently a new treatment method using radiofrequency catheter ablation has emerged with promising results. The techniques described earlier with extensive ablation from both sides of interventricular septum caused atrioventricular block in 20% of the patients, most of them received ICD implants or pacemaker. We performed transesophageal echocardiography to guide focused ablation of left ventricular septum in eight patients and a his bundle quadripolar catheter on the right side to avoid damage to His purkinje system. One of those was excluded from the study for presence of atrial fibrillation during the procedure, rendering us unable to measure gradient reduction. All seven patients underwent cardiac MRI, Echocardiogram, 6 min walk test and Minnesota QOL score before procedure and were scheduled to repeat after 2 month, 6month and one year of ablation. Results: The median age was 55,2 years. Medium Gradient was 102,5mmHg. One patient (patient 1) already underwent previous myectomy, one had a failed Alcohol septal ablation (patient #7), while the other five were procedure naive. The ablation was performed during general anaesthesia, and lesions using 8 mm catheter, 80W, 60 0C, 120 second lesions. 10 to 30 lesions were performed, and the desired procedural endpoint was reduction of at least 25% of initial LV maximum gradient. The reduction of the gradient happened in patients 1, 3, 4, 5, 6 and 7. Patient #2 presented a brief reduction during procedure with recurrence during the first 20 minutes. All seven patients presented gradient increase during the first 24 hour in ICU (per protocol) with progressive decrease during the first week, probability related to edema. Five patients have already completed the two month follow up. Among these five all that presented intraprocedural reduction of gradient also presented improvement of symptoms by the end of the second month (average reduction on the follow up of the five from 117,8mmhg to 53,4mmHg, a 55% reduction in maximum gradient). All four patients with gradient reduction at the end of two month had QOl scores increased and NYHA class reduced at least one point. There were no clinical complications, there was no increase in QRS duration or HV interval. (Figure presented) Conclusion: Echocardiography guided catheter radiofrequency ablation of septum is feasible and accomplished clinical improvement and sustained gradient reduction through the end of 2 month post ablation.