A Vital Clue to the Problem

ANSWER

The correct interpretation is a bit challenging. You’ve confirmed the electrodes were placed correctly; however, the P waves are unusual (best seen in lead II) and are suggestive of an ectopic atrial rhythm. In lead II, there are two P waves for each QRS complex, consistent with second-degree atrioventricular (AV) block with 2:1 AV conduction. The QRS complex is wide at 130 ms without a right or left bundle branch pattern, consistent with a nonspecific intraventricular conduction block, and there is evidence of nonspecific ST-T wave abnormality.

These changes were new compared with the patient’s preoperative ECG, which showed sinus rhythm and no evidence of heart block.