Implantable medical device and method for monitoring synchronicity of the ventricles of a heart

A method for monitoring ventricular synchrony of a heart in an implantable medical device comprising a pace pulse generator adapted to produce cardiac stimulating pacing pulses and being connectable to at least one medical lead for delivering stimulation pulses to cardiac tissue of said heart, said method comprising

• measuring, during impedance measuring sessions, impedance signals by an electrode configuration being located such that said impedance signals substantially reflect septal wall movements, wherein the electrodes of said electrode configuration are connectable to said implantable medical device;
• processing said impedance signals to determine an impedance signal morphology and to detect impedance amplitude peaks in said impedance signal morphology;
• and
• determining a synchronicity index indicating a degree of synchronicity based on detected impedance peaks, wherein at least two impedance peaks detected within a predetermined time window including a cardiac cycle or a part of a cardiac cycle indicate an increased dyssynchronicity in the ventricular contractions.

A method for optimizing lead and/or electrode locations, said electrodes being connectable to an implantable medical device comprising a pace pulse generator adapted to produce cardiac stimulating pacing pulses and being connectable to at least one medical lead for delivering stimulation pulses to cardiac tissue of said heart, comprising:

• a) measuring impedance signals at a first electrode configuration being located such that said impedance signals substantially reflects septal wall movements, wherein the electrodes of said electrode configuration are connectable to said implantable medical device and are located at a right side and/or left side of said heart;
• b) processing said impedance signals to determine an impedance signal morphology and to detect impedance amplitude peaks in said impedance signal morphology;
• c) determining a synchronicity index indicating a degree of synchronicity based on detected impedance peaks for said first electrode configuration, wherein at least two impedance peaks detected within a predetermined time window including a cardiac cycle or a part of a cardiac cycle indicates an increased dyssynchronicity in the ventricular contractions;
• d) performing an optimization procedure based on said synchronicity index by iteratively adjusting a VV-interval so as to minimize said synchronicity index in said predetermined time window for said first electrode configuration;
• e) repeating (a)-(d) for at least a second electrode configuration;
• f) comparing said minimum synchronicity index for each configuration to identify an overall minimum synchronicity index;
• and
• g) selecting the electrode configuration being associated with the minimum synchronicity index.

A system for optimizing lead and/or electrode locations including an implantable medical device, said device comprising:

• a pace pulse generator that emits cardiac stimulating pulses and is connectable to at least one medical lead for delivering said stimulation pulses to cardiac tissue of said heart;
• an impedance measuring unit that, during impedance measuring sessions, measures impedance signals obtained at a first electrode configuration being located such that said impedance signals substantially reflects septal wall movements, wherein the electrodes of said electrode configuration are connectable to said device;
• an impedance peak detecting unit that processes said impedance signals to determine an impedance signal morphology and to detect impedance amplitude peaks in said impedance signal morphology;
• a synchronicity index determining unit that determines a synchronicity index indicating a degree of synchronicity based on detected impedance peaks for said first electrode configuration, wherein at least two impedance peaks detected within a predetermined time window including a cardiac cycle or a part of a cardiac cycle indicates an increased dyssynchronicity in the ventricular contractions;
• a VV delay determining unit that performs an optimization procedure, in which said pace pulse generator is controlled, based on said synchronicity index, to iteratively adjust a VV-interval so as to minimize said synchronicity index in said predetermined time window;
• and
• an external control unit connectable to said implantable medical device and being configured to:
• instruct said implantable medical device to obtain a synchronicity index for at least a second electrode configuration;
• compare said minimum synchronicity index for each configuration to identify a overall minimum synchronicity index;
• and
• select the electrode configuration being associated with the minimum synchronicity index.

An pacing analyzer for optimizing lead and/or electrode locations being connectable to at least one medical lead implantable in a heart of a patient, said analyzer comprising:

• a pace pulse generator that emits cardiac stimulating pulses and is connectable to at least one medical lead for delivering stimulation pulses to cardiac tissue of said heart;
• an impedance measuring unit that, during impedance measuring sessions, measures impedance signals obtained at an electrode configuration and/or lead configuration being located such that said impedance signals substantially reflects septal wall movements, wherein the electrodes of said electrode configuration are connectable to said device;
• an impedance peak detecting unit that processes said impedance signals to determine an impedance signal morphology and to detect impedance amplitude peaks in said impedance signal morphology;
• a synchronicity index determining unit that determines a synchronicity index indicating a degree of synchronicity based on detected impedance peaks for said electrode configuration, wherein at least two impedance peaks detected within a predetermined time window including a cardiac cycle or a part of a cardiac cycle indicates an increased dyssynchronicity in the ventricular contractions;
• a VV delay determining unit that performs an optimization procedure, in which said pace pulse generator is controlled, based on said synchronicity index, to iteratively adjust a VV-interval so as to minimize said synchronicity index in said predetermined time window;
• and
• a control unit configured to:
• compare said minimum synchronicity index for different electrode and/or lead configurations to identify a overall minimum synchronicity index;
• and
• indicate the electrode configuration being associated with the minimum synchronicity index.