A 70 year old man was admitted to the emergency department with shortness of breath and hypotension. He was discharged a week ago from hospital after having undergone an uneventful coronary artery bypass grafting procedure.

a)  What is the major abnormality on the ECG and what is the likely diagnosis?

b)  What investigation is required to confirm your diagnosis?

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College Answer

a)  What is the major abnormality on the ECG and what is the likely diagnosis?

Electrical alternans, Pericardial tamponade

b)  What investigation is required to confirm your diagnosis?

Echocardiography.

Discussion

This pattern recognition question is easy marks and requires little thought.

I picked a relatively subtle ECG to put up here; the Google image search bristles with gratuitously obvious examples of electrical alternans.

I expect the College would want their candidates to be able to recognise it when it is not totally obvious.

References

References

The ECG above comes from the LITFL library of ECG clincal cases

In addition, there is an influential paper on this: Usher, Bruce W., and Richard L. Popp. "Electrical alternans: Mechanism in pericardial effusion." American heart journal 83.4 (1972): 459-463.