Electrocardiogram of a 70 year-old woman who presented within 45 minutes of the onset of severe retrosternal chest pain. The patient was given sublingual nitroglycerin which produced hypotension. 12-lead cardiogram showed hyperacute ST segment elevation in the inferior leads. This is the so-called 15-lead cardiogram with leads V4R (mislabeled RV4), V8, V9.

Rate 54/min
PR 0.16 sec
QRS 0.08 sec
QT 0.44 sec
QTc 0.41 sec
QRS axis + 70º

Interpretation: Abnormal ECG. Sinus bradycardia. Hyperacute ST segment elevation in the inferior leads - II, III aVF, and right precordial lead - V4R and reciprocal ST segment depression in the lateral leads indicative of acute inferior wall and right ventricular infarction.

Hypotension responded to parenteral crystaloids. The patient received thrombolytic treatment with no reperfusion (persistent chest pain and ECG changes). She underwent rescue angioplasty and stenting of a severe stenosis in the proximal dominant right coronary artery.