Myocardial Strain Imaging is a Superior Method for Evaluating Papillry Muscle Contractility in Patients With Myocardial Infarction

Abstract

The papillary muscles (PMs) of the left ventricle (LV) are part of the mitral apparatus. They act to hold the chordae tendineae taut by contracting in normal individuals, preventing the mitral leaflets from prolapsing into the left atrium during ventricular systole [1]. Previously, it has been reported that a possible cause of mitral regurgitation (MR) is ischemia of the PM, which is called PM dysfunction [2], in patients with coronary artery disease. On the other hand, a recent study [3] demonstrated that the most important factor to cause ischemic MR is leaflet tethering by an outward displacement of the PM in patients with LV wall remodeling. Accordingly, PM function is vital to mitral valve competence. However, quantitative assessment of PM function is difficult due to the functional and spatial complexity of the mitral apparatus. Recently, it has been recognized that strain imaging reflects differing aspects of myocardial deformation and is relatively independent of whole heart motion or tethering effects [4][5][6]. Therefore, this new modality would be expected to provide a more sensitive assessment of PM systolic function. The aim of the present study was to investigate PM contractility and how it is affected by the adja- Myocardial Strain Imaging is a Superior