Tuesday, May 20, 2008

Myocardial infarction is more common in the morning…

Myocardial infarction is more common in the morning…

· Awakening and arising is associated with adrenergic stimulation

· Adrenergic stimulation leads to elevated blood pressure

· Elevated pressure increases the hemodynamic stress on atheromatous plaque

· This may lead to

a. Plaque rupture/fissuring

b. Plaque erosion/ulceration

· These events predispose the plaque to thrombose

· Thrombosis leads to coronary artery occlusion leading to MI

That is why the peak incidence of MI is between 6 a.m. and 12 noon

Same reason is applicable for MI following emotional stress

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