Myocardial Infarction · Pathology

What is the earliest histological change visible by light microscopy in a myocardial infarct (occurring between 4-12 hours)?

  1. Dense collagenous scar formation
  2. Wavy fibers at the infarct margins
  3. Extensive neutrophilic infiltration
  4. Presence of Anitschkow cells
Show answer and explanation

Correct answer: Wavy fibers at the infarct margins

Between 4 and 12 hours, the earliest changes include edema, hemorrhage, and 'wavy fibers.' Wavy fibers represent non-contractile dead myocytes being stretched and buckled by the contraction of adjacent viable muscle.

Difficulty: Medium Question 4 of 20

Practice all 20 Myocardial Infarction questions

Keep practicing

More Myocardial Infarction questions