Circulatory Case Study 4*


J.M., a forty-six year old Hispanic male, is currently employed as a vice president for a small, regional computer software company. He often works long hours and has little time for "relaxation" or exercise.  One weekend, while playing basketball with his 6-year-old son, J.M. began to feel a "burning" in his chest. Gradually the pain became more severe and J.M. went into the house to lie down and rest. A few minutes after lying down, he complained to his wife that it felt as if someone was pushing down on his chest and that his left arm was starting to "ache". J.M. asked his wife to call 911 for help. When the paramedics arrived, J.M. was conscious and his skin was pale, clammy, and cool. At this time J.M.’s blood pressure was so low that only the systolic pressure could be measured. The systolic blood pressure was measured by palpation and at 70 mm Hg. J.M. presented with a pulse of 45 beats per minute which was weak and irregular.


At the emergency room, an electrocardiogram (ECG) was ordered.  J.M.’s ECG was interpreted by the emergency room physician to be indicative of a myocardial infarction. Upon questioning, J.M. indicated that his father had died of a heart attack at the age of 42 years and that his older brother (50 years of age) has already had two heart attacks and coronary bypass surgery. Blood was drawn from J.M. in an attempt to verify whether he had suffered a myocardial infarction or not. The results of J.M.’s blood chemistry were as follows:


resting pulse - 88bpm

blood pressure = 140 / 97

pH = 7.20

lactate = 3.5 mEq/L

creatine phosphokinase = 75 mU/ml

myocardial component of creatine phosphokinase = 61%


J.M. was admitted to the coronary care unit for stabilization and treatment.  J.M. was prescribed sublingual nitroglycerine for the angina, one buffered aspirin per day, and placed on a strict diet that severely restricted his intake of sodium, saturated fats, sugar and caffeine. He was advised by his physician that an angiogram should be completed to evaluate his arteries for the presence and possible size of atherosclerotic plaques.  Upon discharge, J.M. was urged by his physician to remain on a diet low in salt and fat (especially saturated fat and cholesterol), avoid caffeine, loose weight, stop smoking and minimize the "stress" in his life. He was also told to continue the daily aspirin and use the sublingual nitroglycerin as needed.




1. Trace a drop of blood from the heart to the body and back to the heart. Distinguish between arteries, veins and capillaries both functionally and structurally.

2. Describe the composition and functions of blood.


3. How would J.M.’s  ECG compare to a normal ECG?  In other words, what told the ER physician J.M had a myocardial infarction?


4. What were the risk factors that may have contributed to J.M.’s myocardial infarction?

5. Explain why the pain that J.M. felt was isolated to his left arm.


6. Why were blood lactate and pH changed because of the myocardial infarction?


7. Why were diuretics prescribed for J.M.’s hypertension?


8. What is the function of the sublingual nitroglycerin? Why is aspirin prescribed as a postoperative treatment for J.M.?


9. If bypass surgery is required, how would this procedure minimize future myocardial infarctions and what would be the effect if J.M. does not alter his diet, even after bypass surgery?

*adapted from McGraw Hill Online Learning Center, Essentials of Anatomy and Physiology,3rd ed.Seely/Stephens/Tate