Clinical Applications

The Case of the Overworked Executive

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. As part of his job he often entertains clients and other executives during meals. As a result of his lack of exercise and the amount of eating and drinking he does related to work, J.M. finds that he is gaining weight. Recently he has noticed that he can no longer walk up the flight of stairs to his office without feeling breathless and having a "pounding" heart. He attributes these physical symptoms to both his lack of exercise and the fact that he has smoked 2 packs of cigarettes per day for the past 20 years. During his yearly physical last month he was diagnosed with hypertension and prescribed exercise, a diet low in sodium and fat, and a diuretic. J.M. was also scheduled for a follow-up examination 6 months after his physical.

One weekend, while playing basketball with his 6-year-old son, J.M. began to feel a "burning" in his chest. Since he had recently finished a meal, he attributed this feeling to indigestion. 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 and jaw were starting to "ache". J.M. asked his wife to call 911 for help. While waiting for the paramedics, J.M. collapsed and lost unconsciousness. When the paramedics arrived, J.M. was still unconscious 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. The paramedics followed "normal" procedures and resuscitated J.M. enroute to the hospital emergency room.

At the emergency room, an electrocardiogram (ECG) was ordered. When compared to a normal ECG, J.M.'s ECG was observed to demonstrate an S-T segment depression that 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: pH = 7.20, lactate = 3.5 mEq/L, creatine phosphokinase = 75 mU/ml; myocardial component of creatine phosphokinase = 61%, lactate dehydrogenase = 135 U/ml, and serum glutamate oxalotransferase = 53 U/ml. Based on the combination of the family history, preadmission symptoms, and the results of tests run in the emergency room, J.M. was diagnosed as having suffered a myocardial infarction.

J.M. was admitted to the coronary care unit for stabilization and treatment. While in the coronary care unit his condition and diet were closely monitored and he was allowed to gradually become more active. 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. The results of the angiogram showed fibrous plaques in the coronary arteries. The degree of occlusion was low enough such that angioplasty was selected as the best possible treatment. Upon recovery from a successful angioplasty J.M. was told that unless he modified both his diet and lifestyle, following discharge, a recurrence of atherosclerosis was highly likely. Such a recurrence would most probably result in a second myocardial infarction and correction would require bypass surgery. Also, his life span could be shortened drastically. 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		Define the bold terms in the text.
2		What event does the S-T segment of the ECG represent?
3		What were the risk factors that may have contributed to J.M.’s myocardial infarction?
4		Explain why the pain that J.M. feels is specifically localized as described.
5		Why were diuretics prescribed for J.M.’s hypertension?
6		Why do these enzymes and electrolytes indicate a myocardial infarction and not a different condition?
7		What is the function of the sublingual nitroglycerin?
8		Why is aspirin prescribed as a postoperative treatment for J.M.?
9		Overall, how will the recommended dietary changes, if followed, prove beneficial for J.M.?
10		Specifically, why were blood lactate and pH changed because of the myocardial infarction?
11		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?
12		How do arteries and veins differ in their structure and function?
13		What anatomical structure must the surgeon be especially aware of when completing bypass surgeries and why?