CRT Implant Strategy Using the Longest Electrical Delay for Non-left Bundle Branch Block Patients

This is a prospective, pilot, multi-center, double-blinded, randomized post-market study to assess the effect of left ventricular lead pacing location (guided via QLV measurement vs. standard of care approach) in non-LBBB patients. In the QLV arm the physician will: 1. Assess two branches of the coronary sinus - a non-traditional vessel (inclusive of the anterior region) will be tested first and a traditional free lateral branch will be tested second for LV lead placement. 2. Measure QLV for each of the four cathodes of the left ventricular lead in each branch. 3. Choose the vein branch and cathode with the longest QLV measurement and program a vector based on that cathode. In the standard of care group, the left ventricular lead placement will be carried out according to the physician's standard of care implant approach. The impact of the left ventricular lead position will be evaluated based on the patient's response to CRT utilizing the Clinical Composite Score (cardiovascular death, heart failure hospitalizations, New York Heart Association (NYHA) class, and Patient Global Assessment). Authorized site personnel conducting the NYHA class assessment and Patient Global Assessment will be blinded to the randomization assignment and lead implant technique.