Case Study B – Module 3 (Ch. 14, pages 275-276 in course textbook)
MEDICAL HISTORY
Mr. WT is a 55-year-old African American male who was initially hospitalized in 1996. The patient stated that he had no history of diabetes, angina, or myocardial infarction. He did have a positive history for cocaine use, as recently as 1 week before hospitalization. He had strong family history of ischemic heart disease and denied alcohol and tobacco use. He worked as a computer programmer and was sedentary during leisure.
DIAGNOSIS
At the time of admission, Mr. WT complained of being unable to lie flat without being short of breath and said that the condition had worsened over the previous several days. Cardiac catheterization revealed three-vessel coronary artery disease, which included a 20% left main lesion, a 95% stenosis in the left anterior descending artery, total occlusion of the circumflex, and a 70% narrowing in the proximal right coronary artery. An echocardiogram performed during the same admission demonstrated a left ventricular ejection fraction of 30%. Diagnosis was ischemic cardiomyopathy. The patient was discharged from the hospital and scheduled to see a cardiologist in the outpatient clinic later in the week. Medications at the time of hospital discharge were lisinopril, simvastatin, lopressor, digoxin, and furosemide.
The patient was seen in the outpatient clinic 6 days after discharge from the hospital. Blood lipids were obtained, revealing total cholesterol of 227 mg∙dl-1, high-density lipoprotein cholesterol of 27 mg∙dl-1, and low-density lipoprotein cholesterol of 172 mg∙dl-1. A dobutamine echocardiogram showed improved contractility. Based on this test and the cardiac catheterization results, coronary bypass surgery was recommended. The patient refused surgery, opting for medical management, lifestyle changes, and cardiac rehabilitation.
EXERCISE TEST RESULTS
Before the patient enrolled in cardiac rehabilitation, a graded exercise test was completed. Resting blood pressure was 138/96 mmHg. Resting ECG showed sinus rhythm with a rate of 72 beats per min. Heart rate during seated rest was 74 beats per minute. Occasional ventricular premature beats were noted at rest, along with left ventricular hypertrophy. An old anterior-lateral infarction pattern was present, age indeterminate.
The patient exercised for 6 min on a treadmill to a peak VO2 of 17.2 mL/kg/min. Chest pain was denied and exercise was stopped because of fatigue and dyspnea. Peak HR was 123 beats per minute, peak blood pressure was 158/98 mmHg, and 1.0 mm additional ST-segment depression was observed in lead V6. Isolated ventricular premature beats were again observed.
EXERCISE PRESCRIPTION
Mr. WT’s goal was to make important and aggressive changes in his lifestyle, including increasing his activity levels from being inactive to exercising 4 or 5 days per week. During rehabilitation, he was able to tolerate 30 min of exercise without complication. The training HR range in this patient that corresponds to 60% to 70% of heart rate reserve is 103 to 108 beats per min.
DISCUSSION QUESTIONS (limit of 500 words per question)
1. Given Mr. WT’s history of being inactive during leisure, what is the likelihood that he will be following a regular exercise program three years in the future? What steps can you take now to ensure long-term compliance?
2. Which symptoms did Mr. WT complain of at the time of hospitalization that were consistent with the diagnosis of cardiomyopathy or heart failure?
3. What target levels would you recommend that Mr. WT achieve for his blood lipid levels?
4. Based on data from Mr. WT’s exercise test, did he show chronotropic incompetence? Is this common or an uncommon finding in patients with HF?
5. Given the VO2peak measured during his exercise test, what magnitude of improvement, if any, would you expect after 12 weeks of exercise training? How would this compare with the improvement that would occur in a sedentary, apparently healthy person who undergoes 12 weeks of training?
