Question

HiStructions: Read the following case study and answer the questions K.R. is a 46-year-old man admitted to the emergency department with unremitting chest discomfort. The pain started while he was shoveling snow from his walkway. He had experienced chest discomfort with activity previously, but the pain had subsided with rest and he sought no medical help. This time the pain did not subside and became increasingly severe, radiating to his left arm and lower jaw. In the emergency department, an ECG and cardiac enzymes were obtained. The cardiac monitor showed sinus tachycardia with occasional premature ventricular complexes. K.R. was treated with 2 L nasal oxygen, thrombolytic therapy, sublingual nitroglycerin, and IV morphine sulfate. When he was pain free, he was transferred to the cardiac unit for monitoring. Discussion Questions 1. What electrocardiographic changes would indicate that K.R. has acute coronary syndrome (ACS)? 2. What changes in "cardiac enzymes" would be consistent with a diagnosis of MI? 3. What is the most common pathophysiologic precipitating event for ACS? What differentiates USA (Unstable Angina) from MI?

Answer 1

1. There is a series of ECG changes that occur in myocardial infarction.

In the initial stage of MI, there is hyperacute "T" wave or "ST" elevation seen at a later stage it may develop to "T" wave inversion.

The common ECG changes for MI is "ST" elevation.

2.

CPK - MB (creatinine phosphokinase) and Troponin are the main 2 cardiac enzymes used to diagnose myocardial infarction. Damaged cardiac muscle release these enzymes into the blood circulation, the elevated amount of these enzymes shows cardiac muscle damage.

CPK - MB normal range is - 5 to 25 IU/L

Tropine normal range is - <0.01ng/ml

3.

ACS(Acute coronary syndrome) - It is a group of signs and symptoms that occur due to any blockage in the coronary artery.

Blockage in the coronary artery restricts blood flow to cardiac muscles, by which cardiac muscles unable to functions properly and start dying. Which causes severe pain in chest, neck, and jaw even at rest.

Unstable angina - It is not a disease like MI, it is a condition in which heart muscles start dying due to lack of oxygen supply and cause severe chest pain. Chest pain gets worse with time and the intensity increase even with rest.

MI - it is otherwise known as heart attack, in this condition the heart muscle dies due to lack of blood supply to heart muscle.