Coronary arteries Coronary anatomy on ECG- Localizing Ischemia interventricular atrioventricular myocardial infarction sinoatrial st-elevation myocardial infarction two arteries that originate from the root of the aorta behind the cusps (aortic sinus) of the aortic valve left posterior left CA anterior aortic sinus right CA myocardium right coronary artery posterior descending right atrium ventricle SA AV nodes inferior MI leads II III aVF bradycardia heart blocks problems posterior MI V1 V4 leads anterolateral left main circumflex descending septum ventricle apex anteroseptal occlusion dominant T wave flattening inversion transmural reciprocal depression limb leads precordial leads