I think you mean right coronary artery. Right ventricular branch is usually a branch of right coronary artery, blockage of this branch is usually of not much consequence unless it is associated with blockade of the parent right coronary artery.
Right coronary supplies the inferior or the undersurface of heart in most cases (75% cases). In 30% cases this artery also supplies additional lateral (outer wall) of the heart. All this information can be obtained by an angiogram (invasive or non invasive). There are small number of cases in which the right coronary artery is anatomically small and the blood of the undersurface of the heart is supplied by left circumflex artery.
Eighty percent narrowing of a right coronary artery in most cases is a significant problem if the blockade is present before the major branches.