The heart is divided into two sides, the left and right. The right side of the heart receives oxygen-depleted blood from the body and pumps it to the lungs for oxygen replenishment. The left side of the heart receives oxygen-rich blood from the lungs, and pumps it back into the body, for delivery to all organ systems.

How the Heart Works
As the heart relaxes and contracts, the chambers fill and pump. Similar to the other muscles in your body, when the heart becomes diseased or injured it weakens, losing its ability to pump sufficiently. This is referred to as ventricular failure, or, more generically, heart failure.

Heart failure can strike the left, right or both sides of the heart. There are different levels of assist for a failing heart; the extent of the failure will determine which drug or device will be most effective.