Recognition, assessment and management of the mechanical complications of acute myocardial infarction

Introduction
Mechanical complications post-acute myocardial infarctions (AMIs) are rare, but may have dramatic and potentially lethal consequences. Most often, the left ventricle is affected and complications are classified based on their onset after the primary event as acute or subacute (within days to weeks) and chronic (within weeks to years). The common underlying mechanism involves excessive, transmural myocardial necrosis followed by the rupture or extensive scarring of the affected tissue (figure 1). Survival of medically treated patients is extremely poor. The diagnosis of an acute or subacute event requires urgent surgical referral and in most cases necessitates emergency surgery. Mortality after surgical treatment is also high, rendering decision making complex.
The incidence of excessive myocardial necrosis and the subsequent rupture of the ischaemic myocardium were grossly reduced after the introduction and routine use of primary reperfusion therapies in the management of AMI. Still, clinicians can expect to encounter this life-threatening entity in a minority (around 1%) of all AMI cases. In this review article, the recognition, assessment and management of ventricular septal rupture (VSR), papillary muscle rupture (PMR) and dysfunction, free wall rupture (FWR), left ventricular (LV) aneurysm and pseudoaneurysm formation after AMI will be discussed in detail. Other mechanical consequences of myocardial dysfunction in AMI as global or regional left ventricular or right ventricular failure or chronic ischaemic mitral regurgitation (MR) are not classified as mechanical complications and will not be discussed in this article.