Complications of Myocardial Infarction: Papillary Muscle Rupture

Abstract

The mitral valve leaflets are supported through the papillary muscle projections from the left ventricular wall and their tendinous cords which extend to the leaflet margins and the belly of the leaflets (Fig. 4.1). There are usually two primary papillary muscle complexes, supero-lateral (antero-lateral/anterior) and infero-septal (postero-septal/posterior). The true anatomical descriptive name is used first but the papillary muscles are frequently simply referred to as anterior or posterior in the surgical forum (Fig. 4.2). They have a relatively discreet and still relatively poorly understood blood supply with little or no collateralisation. The posterior (infero-septal) papillary muscle derives its blood supply from either branches of the right coronary artery or the circumflex branch of the left in a left dominant system. Work done by Voci et al. [1] demonstrated that the situation was sometimes not even that straight forwards and that in a right dominant coronary situation the inferior wall may be perfused by the right coronary artery, whereas the inferior papillary muscle was not. A combination of right coronary occlusion and significant circumflex artery disease in the setting of a dominant right coronary artery is the usual presentation. The incidence is low, less than 5% of myocardial infarctions. More commonly found is inferior wall dyskinesia with acute functional mitral regurgitation.