Which statements about the pathophysiological difference between chest pain from an ischemic episode and chest pain from an infarction episode is CORRECT?

A. Ischemic pain is the result of poorly perfumed lungs and the heart falters.
B. Ischemic pain is never relieved by nitroglycerin.
C. Infarction is commonly the result of a totally occluded coronary blood vessel.
D. Infarction is typically the result of the patient's not taking prescribed cardiac medication.

Answer: C. Infarction is commonly the result of a totally occluded coronary blood vessel.
An acute myocardial infarction typically is the result of coronary artery disease that causes severe narrowing or complete blockage of the coronary arteries. A plaque erosion or rupture within the coronary artery may cause the narrowing and blockage to occur. When the blood flow is blocked, the heart muscle becomes ischemic (hypoxic from inadequate oxygenation). If the blood flow is not restored to the portion of the heart muscle, the cells will begin to die. Ischemic heart tissue will become irritable. It may produce abnormal beats in the conduction system that could lead to dysrythmias. Some dysrythmias, such as ventricular fibrillation and ventricular tachycardia, may be fatal. Ventricular fibrillation, which is the most common dysrhythmia that most patients suffer initially in cardiac arrest, usually occurs within the first hour after the onset of symptoms of a heart attack.