Implantable cardiac pacemaker with automatic by sympatho - vagal balancing of a controlled operating-mode switchover

摘要

An implantable dual-chamber (12, 13) pacemaker system (10) is provided having means for an automatic beat-to-beat adjustment of the maximum allowable variation (MAV) of the sensed atrial rate (AR) as a function of the sympatho-vagal balance, switching from an atrial tracking mode of operation (e.g. DDD or DDD(R)) to a non atrial tracking mode (e.g. VDI or VDI(R)) when either an arrhythmic tachycardic rate, exceeding the MAV, or a sinus tachycardic rate, exceeding the maximum tracking atrial rate (MTAR), is detected. The pacemaker provides logic means for continuously determining the atrial rate variation (ΔAR) and the MAV, whereby the MAV defines the upper limit for the ΔAR above which tracking is not allowed, discriminating between physiological rate variations and arrhythmic variations. The pacemaker system further includes the capability of returning to an atrial tracking mode of operation if the AR remains under a defined rate for a defined number of cycles. In a preferred embodiment the sympatho-vagal balance is expressed by a proper index of the variability of heart rate (HRV).