P1708 Analysis of ventricular mechanics in echo-guided endocardial radiofrequency septal ablation for hypertrophic obstuctive cardiomyopathy

Abstract

Introduction Hypertrophic Obstructive Cardiomyopathy (HOCM) is an important cause of sudden death and heart failure, specially in young adults. Approximately 5% to 8% of patients are not suitable for transcoronary ablation, if myectomy is not feasible, Endocardial Radiofrequency Ablation of Septal Hypertrophy (ERASH) has shown acceptable efficacy and safety for left ventricular outflow tract (LVOT) gradient reduction. 20 ERASH cases have been reported in the literature. Case report 39 year old woman with diagnosis of HOCM, symptoms of dyspnea (NYHA III), and aborted sudden death as first clinical manifestation; a cardiac defibrillator was implanted. A transthoracic echocardiogram (TTE) revealed normal left ventricle (LV) ejection fraction, moderate mitral regurgitation (systolic anterior valve motion), basal inter-ventricular septal wall thickness of 20 mm generating a LVOT gradient of 51 mmHg. A coronary angiography showed inadequate septal branch anatomy to perform alcohol ablation. The patient refused myectomy. Heart Team decided to perform ERASH. Using a 3D Cardiac Mapping System and 2D Echocardiography, the basal interventricular septum received 50 Watts/50˚C radiofrequency ablation without any acute complication. Three days later, a TTE showed LVOT gradient 26 mmHg. The description of the LV mechanics is described on Table 1. Pre and post ERASH ventricular mechanics was analyzed including circumferential endocardial and mesocardial strain and strain rate, as well as longitudinal strain involved in the LV segments that received ERASH (Figure 1.) . Conclusion We report the analysis of ventricular mechanics after a successful case of ERASH, an alternative technique for treating HOCM. In our analysis, pre- ERASH longitudinal strain was significantly more negative at the basal anterior and anteroseptal segments than the other LV segments. This may be a predictor of focal LV remodeling at these segments in the future. Table 1. Pre ERASH Post ERASH Ventricular Segment Strain Strain Rate Strain Strain Rate Longitudinal Strain Basal Anteroseptal -14.4% -1.2 1/s -7% -0.6 1/s Endocardial Circumferential Strain Basal Anteroseptal -13.7% -1.9 1/s -32% -2.2 1/s Basal Anterior -44.6% -4.2 1/s -18.6% -1.6 1/s Mesocardial Circumferential Strain Basal Anteroseptal -7.7% -1.0 1/s -20.2% -1.2 1/s Basal Anterior -24.9% -1.7 1/s -13.8% -0.9 1/s Left ventricular mechanics pre and post ERASH. Abstract P1708 Figure 1.