Progressive Care Nursing Certification (PCCN) Practice Exam

What should the nurse anticipate for a patient with new-onset left bundle branch block after morphine administration for unstable angina?

1. Electrophysiology study

2. Transesophageal echocardiogram

3. Evaluation for fibrinolytic therapy contraindications

4. Troponin I levels

The correct answer is: Troponin I levels

In a situation where a patient presents new-onset left bundle branch block (LBBB) following morphine administration for unstable angina, it is essential to evaluate the patient's cardiac enzyme levels, specifically troponin I. LBBB can indicate underlying myocardial ischemia or infarction, particularly in the context of unstable angina. Troponin I is a specific marker for cardiac muscle injury, and measuring its levels helps determine whether there has been significant cardiac tissue damage. Elevated troponin levels would suggest that the patient may be experiencing a myocardial infarction, which necessitates immediate intervention and further evaluation. The other options present different diagnostic paths: an electrophysiology study focuses on assessing the electrical activity and conduction pathways of the heart, a transesophageal echocardiogram provides detailed images of the heart's structure but may not be immediately relevant in acute settings, and evaluating for fibrinolytic therapy contraindications is more pertinent in cases where a myocardial infarction is confirmed. However, ascertaining the presence of myocardial injury through troponin I levels is the most immediate and relevant step in this clinical scenario.