Ederly Woman Experiences Chest Pain While Knitting

ANSWER
The ECG shows normal sinus rhythm with a short PR interval, right bundle branch block, and an inferior myocardial infarction. The PR interval may vary based on age and heart rate, but is generally accepted as ranging between 120 and 200 ms.

Criteria for a right bundle branch include a QRS complex > 120 ms, a terminal broad S wave in lead I, and an RSR’ complex in lead V₁. An inferior wall myocardial infarction is evidenced by significant Q waves and T-wave inversions in the inferior leads II, III, and aVF.

This case illustrates that an ECG may be of little value in the setting of an ascending aortic dissection. This patient succumbed to rupture of her aortic dissection shortly after admission.