Physiological Adaptation Q 119

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After myocardial infarction, serum glucose levels and free fatty acids are both increased. What type of physiologic changes are these?

  

     A. Electrophysiologic

     B. Hematologic

     C. Mechanical

     D. Metabolic

    

    

Correct Answer: D. Metabolic

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Both glucose and fatty acids are metabolites whose levels increase after myocardial infarction. Acute myocardial infarction evokes a characteristic neurohumoral response: Catecholamine release is increased, plasma contents of free fatty acids and glucose are elevated and glucose tolerance is diminished.

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Option A: Mechanical changes are those that affect the pumping action of the heart. The main mechanical complications (MC) of acute myocardial infarction are ventricular septal rupture(VSR), free wall rupture (FWR), and ischemic mitral regurgitation (IMR). In the chronic phase, negative remodeling and aneurysm formation may occur.

Option B: Hematologic changes would affect the blood. It has been documented that WBC associates through coronary atherosclerosis and ESR in myocardial infarction. Variations occur in hematological parameters such as hemoglobin, WBC, ESR, and platelet sedimentation rate, and fibrinogen in acute myocardial infarction.

Option C: Electrophysiologic changes affect conduction. When coronary blood flow is inadequate to support the oxygen needs of the myocardium (i.e., an ischemic state), tissue levels of oxygen fall, which leads to cellular hypoxia. Severe and prolonged hypoxia can ultimately lead to cellular death and total loss of electrical activity. Less severe hypoxia, or hypoxia of relatively short duration, will produce electrophysiological (and mechanical) changes in the heart.

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