A method of operating a counterpulsation device (CPD) in a human or animal subject is disclosed, the method including: receiving a heart beat signal indicative of the heart beat of the subject; providing counterpulsation therapy by controlling the pressure supplied to a CPD drive line in pneumatic communication with the CPD to cause the CPD to alternately fill with blood and eject blood with a timing that is determined at least in part based on the heart beat signal; while providing counterpulsation therapy, receiving a CPD drive line pressure signal indicative of the pressure in the CPD drive line; and adjusting the pressure supplied to the drive line based at least in part on the drive line pressure signal.