Final answer:
Contraction band necrosis typically occurs within the first 24 hours following a myocardial infarction and is associated with reperfusion injury.
Step-by-step explanation:
Contraction band necrosis is a specific type of myocardial necrosis that can appear after a myocardial infarction (MI), commonly known as a heart attack. This condition is typically observed within the first 24 hours following the MI. It is characterized by hypercontracted sarcomeres, generally a result of reperfusion injury when blood supply returns to the affected area after an ischemic event. Contraction band necrosis signals the onset of myocardial cell death due to lack of oxygen and is one element among various histological changes that can be used to estimate the timing of an MI.