A randomization visit will occur approximately 14 days after implant. Patients will be randomized (like a flip of a coin) to one of two groups. Each patient will have an equal chance of being randomized to either of the two groups. One group will receive cardiac resynchronization treatment (CRT ON) and the other group will not receive cardiac resynchronization treatment (CRT OFF). Patients in the CRT OFF group can receive cardiac resynchronization treatment at 6 months after randomization if the doctor determines that it is appropriate.