Imaging reveals a major blockage of his right coronary aery near the crux of the hea just proximal to the origin of the posterior interventricular aery. Which pa of the hea would be affected by the ischemia that results from this blockage ?

The AV nodal aery, which branches from the right coronary aery proximal to the origin of the posterior interventricular aery, usually supplies the AV node. Option A: The SA node is supplied by the SA nodal aery, a branch of the proximal pa of the right coronary aery, or by the circumflex branch of the left coronary aery. Option C: The left anterior interventricular aery (LAD) supplies the anterior two thirds of the interventricular septum. Option D: The marginal branch of the right coronary aery supplies most of the right ventricle. Its origin is well proximal to the crux of the hea and would not be affected by this blockage. Note: The crux of the hea is the area on the lower back side of the hea where the coronary sulcus (the groove separating the atria from the ventricles) and the posterior interventricular sulcus (the groove separating the left from the right ventricle) meet.