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Case Studies on Cardiac Function

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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 …show more content…

ST depression and T-wave changes may also indicate the development of a non Q-wave MI.

An old MI is evidenced by larger than normal Q waves.

2. What changes in “cardiac enzymes” would be consistent with a diagnosis of MI?

TROPONINS – Markers of choice. Elevated between 4 and 6 hours after the onset of an acute MI and remains elevated for 8-12 days.

MYOGLOBIN – Levels rise between 1 to 4 hours after the onset of chest pain. Highly sensitive.

CREATINE KINASE – comprises of three isoenzymes. 1. Creatine kinase with muscle subunits (CK-MM), which is found mainly in skeletal muscle. 2. Creatine kinase with brain subunits (CK-BB), predominantly found in the brain. 3. Myocardial muscle creatine kinase (CK-MB), found mainly in the heart.

*CK-MB levels increase within 3 to 12 hours of onset of chest pain.
*Reach peak within 24 hours, and return to baseline after 48 to 72 hours.
*Levels peak earlier if perfusion occurs.
*Sensitivity is approximately 95%, with very high specificity.

3. What is the most common pathophysiologic precipitating event for ACS? What differentiates USA from MI?

MI plaque rupture followed by thrombus formation at the site as the precipitating event.

4. What is the rationale for using thrombolytics in the management of STEMI?

It binds to the fibrin of fresh clots and the resulting compound converts adjacent plasminogen into

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