Implantable medical device configured to provide an intra-cardiac function
An implantable medical device configured to provide for an intracardiac function, the implantable medical device comprises a body, a sensor arrangement arranged on the body and configured to receive cardiac sense signals, and a processing circuitry operatively connected to the sensor arrangement. The processing circuitry is configured to process cardiac sense signals received using the sensor arrangement to detect a signal deflection potentially indicative of an atrial event caused by atrial activity to obtain an atrial detection, to detect a signal deflection indicative of a ventricular event caused by ventricular activity succeeding said atrial detection, to determine an atrial-ventricular interval representing a time between the atrial detection and the ventricular event, and to identify the atrial detection as valid or invalid based on the atrial-ventricular interval.
1 . An implantable medical device configured to provide for an intracardiac function, the implantable medical device comprising:
a body;
a sensor arrangement arranged on the body and configured to receive cardiac sense signals; and
a processing circuitry operatively connected to the sensor arrangement, wherein the processing circuitry is configured to process cardiac sense signals received using the sensor arrangement:
to detect a signal deflection potentially indicative of an atrial event (As) caused by atrial activity to obtain an atrial detection,
to detect a signal deflection indicative of a ventricular event (Vx) caused by ventricular activity succeeding said atrial event (As),
to determine an atrial-ventricular interval (AVI) representing a time between the atrial detection and the ventricular event (Vx), and
to identify the atrial detection as valid or invalid by comparing said atrial-ventricular interval (AVI) to an exclusion interval (PVI) and identifying the atrial detection as valid if the atrial-ventricular interval (AVI) is longer than the exclusion interval (PVI) and as invalid if the atrial-ventricular interval (AVI) is shorter than the exclusion interval (PVI).
2 . The implantable medical device according to claim 1 , wherein said sensor arrangement is implemented by an electrode arrangement configured to receive electrical signals as cardiac sense signals.
3 . The implantable medical device according to claim 1 , wherein the body is formed by a lead which is connectable to a generator of the implantable medical device.
4 . The implantable medical device according to claim 1 , wherein the body is formed by a housing of a leadless pacemaker device.
5 . The implantable medical device according to claim 1 , wherein the processing circuitry is configured to determine a peak amplitude (PA) associated with the atrial detection if the atrial detection is identified as valid.
6 . The implantable medical device according to claim 5 , wherein the processing circuitry is configured to determine the peak amplitude (PA) associated with the atrial detection in a peak detection window (PDW) following the atrial detection.
7 . The implantable medical device according to claim 6 , wherein the processing circuitry is configured to determine whether a portion of the peak detection window (PDW) overlaps with the exclusion interval (PVI) and to exclude data received within said portion when determining said peak amplitude (PA).
8 . The implantable medical device according to claim 5 , wherein the processing circuitry is configured to update, using the peak amplitude (PA), a sense threshold (ST) for detecting a subsequent atrial event (As).
9 . The implantable medical device according to claim 8 , wherein the processing circuitry is configured to update the sense threshold (ST) using an average threshold reference based on the equation
ST ( t )= PC·ATR ( t ),
where ST(t) is the current sense threshold, PC is a percentage ratio, and ATR(t) is the current average threshold reference.
10 . The implantable medical device according to claim 9 , wherein the current average threshold reference is determined by the equation
ATR ( t )= W·PA ( t− 1)+(1− W )· ATR ( t− 1),
where W indicates an update weight, PA(t−1) is the peak amplitude as determined for the previous cycle t−1, and ATR (t−1) is the previous average threshold reference.
11 . The implantable medical device according to claim 1 , wherein the processing circuitry is configured to count a cardiac cycle during which the atrial detection occurred as a missed cycle if the atrial detection is identified as invalid.
12 . The implantable medical device according to claim 1 , wherein the processing circuitry comprises a first processing channel having a first gain (G 1 ) for processing a first signal derived from cardiac sense signals received via the sensor arrangement and a second processing channel having a second gain (G 2 ) for processing a second processing signal derived from cardiac sense signals received via the sensor arrangement, the second gain (G 2 ) being higher than the first gain (G 1 ).
13 . The implantable medical device according to claim 12 , wherein the processing circuitry is configured to process the first processing signal to detect a ventricular activity and the second processing signal to detect an atrial activity.
14 . Method for operating an implantable medical device for providing for an intracardiac function, comprising:
receiving, using a sensor arrangement arranged on a body of the implantable medical device, cardiac sense signals; and
processing, using a processing circuitry operatively connected to the sensor arrangement, cardiac sense signals received using the sensor arrangement:
to detect a signal deflection potentially indicative of an atrial event (As) caused by atrial activity to obtain an atrial detection,
to detect a signal deflection indicative of a ventricular event (Vx) caused by ventricular activity succeeding said atrial detection,
to determine an atrial-ventricular interval (AVI) representing a time between the atrial detection and the ventricular event (Vx), and
to identify the atrial detection as valid or invalid by comparing said atrial-ventricular interval (AVI) to an exclusion interval (PVI) and identifying the atrial detection as valid if the atrial-ventricular interval (AVI) is longer than the exclusion interval (PVI) and as invalid if the atrial-ventricular interval (AVI) is shorter than the exclusion interval (PVI).