EKG Quiz #2
You are called to see a 47-year-old male patient in the cardiac intensive care unit. Which of the following is the most likely explanation for these EKG findings?
- A) Acute myocardial infarction
- B) Acute pericarditis
- C) Atrial fibrillation
- D) Cardiac tamponade
- E) Constrictive pericarditis
- F) Pleural effusion
- G) Restrictive cardiomyopathy
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Answer: Cardiac Tamponade
The EKG shows sinus tachycardia with electrical alternans. Electrical alternans is seen here as the alternation of QRS complex amplitude from beat-to-beat.
Electrical alternans is most commonly seen in patients with cardiac tamponade and large pericardial effusions. It is thought to be due to cardiac motion (the heart flopping back and forth) within the fluid filled pericardial sac. This movement changes the electrical axis producing alternating heights of the QRS and p-waves on the EKG.
EKG ©2011 by James Heilman, MD Creative Commons Attribution-Share alike 3.0