Abstract 3357: Pattern and Degree of Reverse Remodelling Following Extended Septal Myectomy for Hypertrophic Cardiomyopathy: An MRI Study
Introduction - Extended septal myectomy for hypertrophic cardiomyopathy (HCM) results in relief of obstruction and improvement of symptoms. However, the effect of surgery on regional ventricular remodeling is not known. The aims of this study were to evaluate the pattern, extent and functional impact of ventricular remodeling after surgery.
Methods - From 2006 to 2008, 46 patients (46±13years, 29 male) underwent extended surgery for symptomatic HCM. Cardiac magnetic resonance was performed before and >6 months after surgery. Regional diastolic wall thickness, wall thickening, left ventricular (LV) mass and LV function were assessed using CMRTools (Cardiovascular Imaging Solutions, London.). The LV was divided into 17 segments according to ACC/AHA guidelines.
Results - Analysis was performed in 12 patients. Preoperative mean septal thickness was 21±4 mm and mean LV outflow gradient was 69±32 mmHg. Following surgery, there was significant regression of LV wall thickness in all regions of the LV, ranging from 13% in the apical anterior region to 38% in the basal anterospetal region (see Figure⇓). Wall thickening was significantly increased in segments remote from the septal region, particularly the basal region (Figure⇓). Mean LV mass decreased significantly after surgery (196±58g vs 251±60g preoperatively; p<0.01). There was little change in LV end-diastolic volume (120±30 mL vs 122±27 mL; p=0.9) with a mild decrease in LV ejection fraction (71±5% vs 80±7%; p=0.05).
Conclusion - Following surgical relief of outflow obstruction for HCM, there is marked regional-specific myocardial reverse remodeling. These changes could have a significant impact on LV dynamics and function.