Heart failure is a progressive disease that decreases the pumping action of the heart. This may cause a backup of fluid in the heart and may result in heart beat changes. When there are changes in the heart beat sometimes an implantable heart device is used to control the rate and rhythm of the heart beat. In certain heart failure cases, when the two lower chambers of the heart no longer beat in a coordinated manner, cardiac resynchronization therapy (CRT) may be prescribed. CRT is similar to a pacemaker. It is placed (implanted) under the skin of the upper chest. CRT is delivered as tiny electrical pulses to the right and left ventricles through three or four leads (flexible insulated wires) that are inserted through the veins to the heart. The purpose of this study is to evaluate a new lead for delivering energy to the left ventricle (bottom left chamber of the heart).