Rupture
of free wall of infarcted ventricle
- occurs
in up to 10% of patients dying in hospital post MI
- Local
factors that lead to rupture:
- thinness
of the apical wall at terminal end of blood supply
- poor
collateral flow
- shearing
effect of muscular contraction against an inert and stiffened necrotic
area
- occurs
more commonly in left versus right ventricle
- usually
involves anterior or lateral walls of ventricle in region of terminal
distribution of LAD coronary artery
- is
usually associated with a transmural infarction of at least 20% of left
ventricle
- occurs
most commonly between 3 — 6 days post infarct
- rarely
occurs in an hypertrophied ventricle or in an area of good collateral
blood supply
- rupture
of free wall of left ventricle usually leads to hemopericardium and death
from cardiac tamponade
- course
of rupture varies from catastrophic with an acute tear leading to
immediate death, or slow and incomplete leading to a late rupture or a
false aneurysm
- incomplete
rupture may occur when the thrombus and haematoma together with the
pericardium seal the rupture of the left ventricle —> may develop into
a left ventricular diverticulum or a false aneurysm
- recognition
of rupture is often first suggested by development of profound right
ventricular failure and shock progressing to electromechanical
dissociation
- immediate
pericardiocentesis will temporarily relieve tamponade followed by CPB to
repair wall ± CABG