A 49-year-old man presents to the emergency department with an 18-hour history of bilateral jaw pain, increasing over the past few hours with associated chest tightness.
Describe and interpret his initial 12-lead electrocardiogram:

DESCRIPTION:
- Sinus rhythm with a ventricular rate of 69 bpm
- Normal PR interval (142 ms)
- Normal QRS axis (8°)
- Borderling prolongued QRS duration (102 ms)
- Poor R wave progression
- Subtle ST-segment elevation in the inferior lead (II, III & aVF)
- Subtle reciprocal downsloping ST-segment depression in lead aVL
INTERPRETATION:
- Inferior ST-segment Elevation Myocardial Infarction (STEMI)
- Nonspecific intraventricular conduction delay
CASE PROGRESSION:
- Coronary angiogram:
- LMCA: Widely patent (unusual take off from high within left sinus).
- LAD: Chronic total occlusion with the mid vessel with severe proximal disease. Distal vessel fills from mature epicardial collateral from distal circumflex. Large calibre distal LAD.
- LCx: Non dominant. Two large OM branches. Mild-moderate disease.
RCA: Dominant. Occluded in mid vessel.
PCI of RCA x2 DES.
- Echocardiogram:
- Normal LV size with mild segmental systolic dysfunction (inferobasal akinesis). EF 50%.
- Normal RV size with mildly impaired systolic function.
- Normal sized atria.
- Mildly sclerotic aortic valve with mild AR.
- Mild dilatation of the aortic root.