Most ruptured chordae tendineae lead to significant volume overload and carry a poor prognosis. The fact that a ruptured chorda tendinea is the cause of valvular incompetence has no direct bearing on the prognosis, except that the signs may be particularly severe immediately after the rupture, before compensation occurs. When a murmur of MR or TR develops in a short period and is associated with clinical signs, a period of box rest during which the animal is given a chance to compensate may be justified in animals which are not expected to perform at an arduous athletic level. However, very few animals will return to work, even if they are only required for hacking, although some may have an adequate quality of life to be kept as a pet. In these circumstances, monitoring the resting heart rate and close observation for signs of tachypnoea and ventral oedema are advisable, so that the horse is not ridden when unsafe and for the welfare of the animal. Ideally, echocardiographic examinations should be repeated at three- to six-month intervals to monitor for signs of deterioration such as increased volume overload or PA dilation which may precede rupture of this vessel.