Abstract 1608: Posterior Shift of the Anterior Papillary Muscle is a Determinant of Improvement after Cardiac Resynchronization Therapy
Background: Cardiac resynchronization therapy (CRT) can improve heart failure symptoms and decrease mitral regurgitation (MR). Improved coordinated timing of mechanical activation of papillary muscle was reported to be a contributor to reduction of MR after CRT.
Purpose: We tested the hypothesis that the anatomical location of anterior papillary muscle (A-PM) affects improvement of MR and other parameters after CRT.
Methods: Twenty-three patients (age 69.8 ± 8.2 years, left ventricular ejection fraction (LVEF) 29.4 ± 6.9%, 16 male, 20 non-ischemic dilated cardiomyopathy, 3 previous myocardial infarcion) underwent both CRT and multi-detector computed tomography (MDCT) were studied. We measured the angle between the anterior edge of the left ventricular free wall and A-PM (Ang. PM) in cross sectional images of left ventricle obtained by MDCT. Patients were divided into 2 groups; 13 patients with severe A-PM displacement (Ang.PM >100 degree) and 10 patients with Ang.PM <100 degree. In both groups, parameters obtained by echocardiography, NYHA functional class, and brain natriuretic peptide before and 6 months after CRT were analyzed.
Results: Mean Ang.PM was 106 ± 12.2 degree. LVEF and NYHA functional class were significantly improved after 6 months of CRT in both groups (p < 0.05, respectively). However, significant decreases of the proportion of grade 2– 4 MR, left ventricular end-systolic and end-diastolic dimensions, and brain natriuretic peptide level after 6 months of CRT were observed only in patients with severe A-PM dislocation (p = 0.02, p = 0.04, p = 0.03 respectively).
Conclusion: Posterior shift of A-PM may have a potential to predict improvement after CRT.