A system, comprising: a connector configured to be connected to at least one implantable lead (110, 114) comprising a right ventricular electrode (124, 126) and one or more left ventricular electrodes (132, 134, 136, 138); at least one processor; and a memory coupled to the at least one processor, wherein the memory stores program instructions, wherein the program instructions are executable by the at least one processor to: determine at least one of: i) a right ventricular to left ventricular (RV-LV) conduction time representative of a conduction time between a right ventricular paced or sensed event and one or more responsive left ventricular sensed events; or ii) a left ventricular to right ventricular (LV-RV) conduction time representative of a conduction time between one or more LV paced or sensed events and an RV sensed event, characterized in that the at least one processor is further configured to: calculate a relation between a threshold and the at least one of the RV-LV conduction time or LV-RV conduction time; and set a pacing mode of an implantable medical device to one of i) a biventricular (BiV) pacing mode and ii) an LV only pacing mode based on the relation. a connector configured to be connected to at least one implantable lead (110, 114) comprising a right ventricular electrode (124, 126) and one or more left ventricular electrodes (132, 134, 136, 138); at least one processor; and a memory coupled to the at least one processor, wherein the memory stores program instructions, wherein the program instructions are executable by the at least one processor to: determine at least one of: i) a right ventricular to left ventricular (RV-LV) conduction time representative of a conduction time between a right ventricular paced or sensed event and one or more responsive left ventricular sensed events; or ii) a left ventricular to right ventricular (LV-RV) conduction time representative of a conduction time between one or more LV paced or sensed events and an RV sensed event, characterized in that the at least one processor is further configured to: calculate a relation between a threshold and the at least one of the RV-LV conduction time or LV-RV conduction time; and set a pacing mode of an implantable medical device to one of i) a biventricular (BiV) pacing mode and ii) an LV only pacing mode based on the relation. i) a right ventricular to left ventricular (RV-LV) conduction time representative of a conduction time between a right ventricular paced or sensed event and one or more responsive left ventricular sensed events; or ii) a left ventricular to right ventricular (LV-RV) conduction time representative of a conduction time between one or more LV paced or sensed events and an RV sensed event, characterized in that the at least one processor is further configured to: calculate a relation between a threshold and the at least one of the RV-LV conduction time or LV-RV conduction time; and set a pacing mode of an implantable medical device to one of i) a biventricular (BiV) pacing mode and ii) an LV only pacing mode based on the relation. calculate a relation between a threshold and the at least one of the RV-LV conduction time or LV-RV conduction time; and set a pacing mode of an implantable medical device to one of i) a biventricular (BiV) pacing mode and ii) an LV only pacing mode based on the relation.