Myocardial Ischaemia (Robbins 6th Ed pp 550)

There are different levels of ischaemia which causes different levels of problems, these are described below:

• Functional ischaemia: there is no damage to cardiac muscle, so pathologically nothing special. Causes angina 》 may progress to arrhythmias 》 causes death.

• Slow-onset occlusion: gradual onset of ischaemia takes some time, allowing for sufficient collaterals to develop. You get fibrinous necrosis, and therefore such areas are replaced by fibrous tissue. Replacement of tissue causes cardiac hypertrophy (i.e.: existing muscle fibres get larger to subsidise for losses), and too much replacement will render “functional syncytium” useless (i.e.: compliance reduction) – heart failure.

• Rapid-onset ischaemia: MI + associated complications (i.e.: arrhythmias)

Category: Pathology Notes