Taking One for the Team

ANSWER

The correct interpretation of this patient’s ECG includes sinus rhythm with a first-degree atrioventricular (AV) block, otherwise within normal limits. A first-degree AV block is diagnosed based on a PR interval > 200 ms, which represents a prolonged conduction time from the sinus node to the ventricles. A 1:1 ratio of P waves to QRS complexes with consistent PR intervals eliminates the possibility of a second- or third-degree heart block.

First-degree AV block is generally a benign finding. However, care should be taken if the patient ever needs medications to slow AV nodal conduction (ie, ß-blockers, calcium channel blockers).

Finally, it may be tempting to consider Wolff-Parkinson-White syndrome based on the delta wave seen in leads V₄ to V₆. But this possibility is ruled out by the presence of a first-degree AV block.