Abstract: An intracardiac pacemaker is configured to filter a raw cardiac electrical signal received by the pacemaker to produce a filtered cardiac electrical signal, analyzes the filtered cardiac electrical signal to establish cardiac event sensing criteria that discriminate P-waves from T-waves and R-waves all present in the raw cardiac electrical signal, and sense the P-waves from the filtered cardiac electrical signal when the established cardiac event sensing criteria are met. Sensed P-waves may be used for controlling atrial-synchronized ventricular pacing delivered by the pacemaker.

Abstract: A pacemaker implantable in a chamber of a patient's heart is configured to produce a filtered cardiac electrical signal by filtering a raw cardiac signal by an adjustable filter of a sensing module of the pacemaker. The sensing module is configured to receive the raw cardiac electrical signal comprising R-waves, T-waves and P-waves via electrodes coupled to the sensing module. The pacemaker is further configured to determine if the T-waves are distinct from the P-waves in the filtered cardiac electrical signal and adjust the filter to increase a difference between a feature of the P-waves and a feature of the T-waves in the filtered cardiac signal when the T-waves are not distinct from the P-waves.

Abstract: An intracardiac pacemaker is configured to receive a cardiac electrical signal developed across a pair of electrodes coupled to the pacemaker and detect a crossing of a first sensing threshold of the cardiac electrical signal. A pacing escape interval timer is set to a first pacing escape interval in response to the cardiac electrical signal crossing the first sensing threshold. The pacing escape interval timer is adjusted if the cardiac electrical signal crosses a second sensing threshold during a time limit.

Abstract: An intracardiac pacemaker is configured to filter a raw cardiac electrical signal received by the pacemaker to produce a filtered cardiac electrical signal, analyzes the filtered cardiac electrical signal to establish cardiac event sensing criteria that discriminate P-waves from T-waves and R-waves all present in the raw cardiac electrical signal, and sense the P-waves from the filtered cardiac electrical signal when the established cardiac event sensing criteria are met. Sensed P-waves may be used for controlling atrial-synchronized ventricular pacing delivered by the pacemaker.

Abstract: A pacemaker implantable in a chamber of a patient's heart is configured to produce a filtered cardiac electrical signal by filtering a raw cardiac signal by an adjustable filter of a sensing module of the pacemaker. The sensing module is configured to receive the raw cardiac electrical signal comprising R-waves, T-waves and P-waves via electrodes coupled to the sensing module. The pacemaker is further configured to determine if the T-waves are distinct from the P-waves in the filtered cardiac electrical signal and adjust the filter to increase a difference between a feature of the P-waves and a feature of the T-waves in the filtered cardiac signal when the T-waves are not distinct from the P-waves.

Abstract: An intracardiac pacemaker is configured to receive a cardiac electrical signal developed across a pair of electrodes coupled to the pacemaker and detect a crossing of a first sensing threshold of the cardiac electrical signal. A pacing escape interval timer is set to a first pacing escape interval in response to the cardiac electrical signal crossing the first sensing threshold. The pacing escape interval timer is adjusted if the cardiac electrical signal crosses a second sensing threshold during a time limit.