The anterior cardiac veins are a variable group of veins that drain a significant portion of the right ventricle. They directly empty into the right atrium above the right atrioventricular groove.
The anterior interventricular vein travels in the anterior interventricular groove with the left anterior descending coronary artery, draining blood from the left ventricular apex, anterior interventricular septum, anterior portions of both ventricles.
The oblique vein of the left atrium is a small vessel that collects blood from the the left atrium. It typically merges with either the great cardiac vein or the coronary sinus.
Small cardiac vein runs alongside the right coronary artery in the right atrioventricular groove and typically drains into the coronary sinus. This vein primarily drains the inferior wall of the right ventricle.