System and method for improving CRT response and identifying potential non-responders to CRT therapy

An implantable cardiac therapy system comprising:

• at least one lead configured for implant in a patient and comprising a plurality of left ventricular electrodes and at least one right ventricular electrode;
• an implantable cardiac therapy device configured to couple to the at least one lead and comprising a controller configured to select an electrode configuration from a plurality of electrode configurations associated with the right ventricular and left ventricular electrodes, to receive sensed activity from the right ventricular and left ventricular electrodes, to determine an interval between sensed activity of the right ventricle and sensed activity of the left ventricle, and to determine, based at least in part on the interval, whether the selected electrode configuration is suitable for delivery of cardiac resynchronization therapy, wherein the determining comprises comparing the interval with a threshold value and determining whether the interval exceeds the threshold value, wherein the controller is operative to switch to another electrode configuration only if the selected electrode configuration is not suitable for delivery of cardiac resynchronization therapy, otherwise to use the selected electrode configuration for delivery of cardiac resynchronization therapy.