Scenario: The top strip was obtained in an 83-year-old woman admitted to the coronary care unit with intermittent chest pain just before going to the cardiac catheterization laboratory for percutaneous coronary intervention (PCI). The patient has a history of coronary artery disease and a permanent pacemaker. The bottom strip was taken upon return to the coronary care unit after a stent was placed in the right coronary artery. The patient was complaining of chest pain, which started during the PCI procedure and never resolved.
Interpretation: (Top Strip) Atrioventricular pacing at 69 beats per minute (bpm) with 1 premature ventricular complex. (Bottom Strip) An intrinsic atrial rhythm is present with ventricular pacing at 72 bpm. The QRS morphology is different, with new ST-segment elevation suggestive of acute inferior myocardial infarction (MI).
In patients with right ventricular paced rhythms (VPR), the endocardial electrode generating the impulse is positioned in the right...