5. The Wavefront of Myocardial Necrosis - Schematic
Ultrastructural evidence of irreversible myocardial damage can be
detected 20 to 40 minutes after occlusion of a major epicardial
coronary artery. Wavy fibre change can be detected with the light
microscope at 1-3 hours, and classic histologic feature of necrosis
are established by 4 - 12 hours. The subendocardial zones become
irreversibly damaged first. There is progressive loss of the
myocardial zone at risk over the next 24 hours, with most of the
damage occurring in the first 4 - 6 hours. What are the implications
of this sequence of events in terms of the beneficial effects of
angioplasty and thrombolytic therapies?
Answer
What would thrombolysis accomplish in this patient if it were given
within 20-40 minutes of the patient's first symptoms? 6-10 hours
later? one day later? What are the sequential effects of ischemia? Is
myocardial necrosis necessary to get arrhythmias?
Answer
