There are several ways where the heart becomes enlarged. Even though a normal heart forces the blood to both ventricles at the same time, an artificial heart is equipped to force the blood only to a ventricle at a moment.
It does help keep a healthy heart though. The organs of the body demand more oxygen, and therefore it tries to fulfill the demand, with extra efforts. Sometimes it may not beat at a regular rate.
A limited stream of blood can cause the weakening of the heart muscle. Together with insufficient blood supply, there may be a drop in blood pressure level which might end up being fatal. A consistently large breathing rate is usually a sign of a heart condition.