Progressive Care Nursing Certification (PCCN) Practice Exam

In a patient with inferior wall myocardial infarction, which 12-lead ECG finding is expected?

1. T wave inversion in leads I and aVL

2. Q wave formation and ST segment elevation in leads II, III, and aVF

3. QRS duration greater than 0.01 in all leads

4. R wave taller in V6

The correct answer is: Q wave formation and ST segment elevation in leads II, III, and aVF

In a patient experiencing an inferior wall myocardial infarction, the expected 12-lead ECG findings include Q wave formation and ST segment elevation in leads II, III, and aVF. This is due to the location of the inferior wall of the heart, which is primarily supplied by the right coronary artery in right-dominant coronary circulation. During an inferior myocardial infarction, ischemia and necrosis affect the myocardium in this region, reflected on the ECG as abnormal Q waves, which indicate myocardial damage, and ST segment elevation, a hallmark sign of acute myocardial injury. The presence of these findings in leads II, III, and aVF correlates with damage to the inferior aspect of the heart. The other options do not align with the typical findings associated with inferior wall myocardial infarctions. For example, T wave inversion in leads I and aVL relates more to lateral wall myocardial involvement. A QRS duration exceeding 0.01 is not specific to myocardial infarction and could indicate other conduction issues. Lastly, an unusually tall R wave in V6 could suggest lateral wall changes or left ventricular hypertrophy rather than an inferior wall MI. Thus, the correct expected finding for an inferior wall MI is indeed Q wave formation and ST segment elevation