Narrator: A biventricular pacemaker stimulates both heart ventricles to pump in a synchronized fashion in order to maximize blood flow.

David Hayes, M.D., Cardiologist
"If you can pace both ventricles to try to improve the way that the ventricles squeeze, you can often improve the patients' symptoms."

Narrator: The biventricular device looks like a standard pacemaker and is implanted in a similar way. One electrical lead is attached to the right ventricle and another, on the upper chamber, or atrium. The difference is the new pacemaker has a third lead, which stimulates the left ventricle. When it's turned on, the failing heart synchronizes and pumps more efficiently.

Standard pacemakers don't work for heart failure patients because they only stimulate one ventricle of the heart to pump. Not all people with heart failure will benefit from the device, but those who do may enjoy dramatic improvements in their quality of life.