Case Studies on Cardiac Function

Case 1
A.O. is an 89-year-old woman with a long history of systolic heart failure secondary to a large left ventricular infarct when she was in her 70s. She had poor activity tolerance and required assistance with activities of daily living. Even minimal activity was associated with moderately severe dyspnea and exertional chest pain, which was relieved by rest. A.O. also exhibited marked pedal edema bilaterally. She is being treated with digitalis, furosemide (Lasix), KCl, and sublingual nitroglycerin.

Discussion Questions

1. Which type of heart failure (left or right sided) is usually associated with dyspnea?

Left-sided

What other clinical findings are likely to be present with left-sided heart failure?

Signs of pulmonary congestion are orthopnea or basilar crackles. Possible cough.
Increased heart rate and S3 heart sound with auscultation.

2. What compensatory mechanisms are likely to be operative in A.O. to enhance cardiac output?

Baroreceptors will detect a low blood pressure and carbon monoxide levels, which would excite the sympathetic system resulting in an increased heart rate. During this mechanism the beta receptors will down regulate leaving this mechanism less effective.

Prolonged stretch on the myocardium will result in myocardial hypertrophy.

3. What is the most likely cause of A.O.’s pedal edema?

Right sided failure causes pedal edema.

4. What is the cause of A.O.’s exertional chest pain? What laboratory tests would be useful to confirm this diagnosis?

Exertional chest pain is probably angina.

Laboratory confirmation would be: * Normal CK with normal isoenzymes. * Normal troponins. * Normal myoglobin.

5. What is the rationale for the use of each of A.O.’s medications in managing her heart disease?

FUROSEMIDE – loop diuretic. Activates