Abstract 10792: Immediate Reduction in Left Ventricular End-Diastolic Pressure During Alcohol Septal Ablation in Patients with Hypertrophic Obstructive Cardiomyopathy

Abstract

Introduction: Alcohol septal ablation (ASA) is an elective nonsurgical procedure proven to be effective for patients with hypertrophic obstructive cardiomyopathy (HOCM). The intraprocedural change in left ventricular end-diastolic pressure (LVEDP) is unknown. In this study we assessed the hypothesis that LVEDP decreases immediately post ablation during ASA in patients with HOCM independently of the effects of sedation and heart rate. Methods: We retrospectively identified 133 elective ASA procedures for patients with HOCM between 2015 and 2021 at our institution using an internally maintained database. Pre- and post-ablation LVEDP measurements were taken using the pressure tracing corresponding with end-expiratory R wave of the ECG tracing. LVEDP was recorded for post-“a” wave points on the pressure tracing at three distinct points during the procedure: the immediate start of the procedure (Group A), prior to alcohol injection after sedation had taken effect (Group B), and post ablation (Group C). Heart rate (HR) and left ventricular outflow tract gradient (LVOTG) were obtained from the catheterization report. Paired t-tests, ANOVA, and regression analyses were performed using SPSS Statistics. Results: The average patient age was 64 years old; mean NYHA Class 2.7; and 67% were women. There was no difference between LVEDP of Groups A and B (32mmHg, 32mmHg, p=0.92). LVEDP between Groups A and C (32mmHg, 26mmHg, respectively; p<0.001) and Groups B and C (32mmHg, 26mmHg, respectively; p<0.001) were significantly different. There was no correlation between HR and LVEDP for the groups (R2A=0.002, R2B=0.000, R2C=0.054), and similarly, no correlation between the average change in LVEDP and the change in resting or provoked LVOTG (R2=0.033, R2=0.003, respectively). Conclusions: These results support that alcohol septal ablation causes an immediate reduction in LVEDP post-ablation independent of heart rate, reduction in LVOTG, and effects of sedation. In conclusion, this instantaneous change in LVEDP may account for the immediate resolution in symptoms reported by patients with HOCM undergoing ASA.