Enslaved active implantable medical device protected from the effects of brady-and/or tachy-dependent extrasystoles

摘要

A rate-responsive active implantable medical device, in particular a cardiac pacemaker, defibrillator or cardiovertor, which is protected from the effects of bradycardia- and/or tachycardia-dependent extrasystoles. The device is able to stimulate at least one cardiac cavity by delivering low-energy pulses to the heart at a frequency determined by the device, and evaluates the activity level of the patient bearing the device and discriminates between phases of rest, normal activity and effort. Further, the device is capable of adjusting the frequency according to the determined activity level, more particularly decreasing the base frequency to a given minimum level during a rest phase. The device also detects the occurrence of brady-dependent extrasystoles, determines a corresponding extrasystole rate, and then increases the base frequency minimum level when the extrasystole rate exceeds a predetermined threshold during the rest phase. In a similar manner, tachy-dependent extrasystoles are diagnosed and the stimulation rate maximum is adjusted (reduced). These adjustments inhibit the appearance of extrasystoles.