Mechanical complications of acute myocardial infarction

Complication

Time course

Involved coronary artery

Clinical findings

Echocardiography findings

Papillary muscle rupture/
dysfunction

Acutely or 3-5 days after MI

RCA
  • Severe pulmonary edema, respiratory distress
  • New soft systolic murmur
  • Hypotension/cardiogenic shock

Severe MR

Interventricular
septum rupture

Acutely or 3-5 days after MI

LAD (apical septal) or RCA (basal septal)
  • Chest pain
  • New harsh holosystolic murmur with thrill
  • Hypotension/cardiogenic shock

Left-to-right ventricular shunt*

Free wall
rupture

Acutely or within 5 days; can occur up to 2 weeks after MI**

LAD
  • Chest pain
  • Distant heart sounds
  • Shock, rapid progression to cardiac arrest

Pericardial effusion with tamponade

Left ventricular
aneurysm

Up to several months

LAD
  • Heart failure
  • Angina
  • Ventricular arrhythmias

Thin & dyskinetic myocardial wall

*Right heart catheterization shows step-up in O2 concentration from right atrium to right ventricle.

**50% of cases occur within 5 days of MI.

LAD = left anterior descending; MI = myocardial infarction; MR = mitral regurgitation; RCA = right coronary artery.