Performing one or more pulse transit time measurements based on an electrogram signal and a photoplethysmography signal

A method comprising:

• collecting, using a plurality of electrodes of a medical device, an electrogram (EGM) signal of a patient, wherein the EGM signal includes a plurality of depolarizations;
• collecting, using an accelerometer of the medical device, an accelerometer signal that indicates which posture of a set of postures that the patient is occupying;
• collecting, using a wearable device, a photoplethysmography (PPG) signal of the patient, wherein the PPG signal includes a plurality of PPG features indicating the occurrence of a cardiac pulse;
• determining, using processing circuitry in communication with a memory, a plurality of pulse transit time (PTT) intervals, wherein a PTT interval of the plurality of PTT intervals corresponds to each depolarization of the plurality of depolarizations, wherein each PTT interval of the plurality of PTT intervals represents an amount of time between a respective depolarization of the set of depolarizations and a PPG feature of the plurality of PPG features that occurs after the respective depolarization and before a subsequent depolarization of the plurality of depolarizations;
• determining, based on the accelerometer signal, a posture of the patient from a plurality of postures corresponding to each PTT interval of the plurality of PTT intervals;
• associating each PTT interval of the plurality of PTT intervals with one or more classifications corresponding to each PTT interval of the plurality of PTT intervals, wherein the one or more classifications indicate the posture of the patient corresponding to the respective PTT interval;
• selecting, from the plurality of PTT intervals, a set of PTT intervals based on the one or more associated classifications for each PTT interval of the plurality of PTT intervals, wherein each PTT interval of the set of PTT intervals is associated with a classification of the one or more classifications indicating at least one posture of a set of postures;
• and
• monitoring, based on the selected set of PTT intervals, a patient condition.

A non-transitory computer-readable medium comprising instructions for causing one or more processors to:

• collect, using a plurality of electrodes of a medical device, an electrogram (EGM) signal of a patient, wherein the EGM signal includes a plurality of depolarizations;
• collect, using an accelerometer of the medical device, an accelerometer signal that indicates which posture of a set of postures that the patient is occupying;
• collect, using a wearable device, a photoplethysmography (PPG) signal of the patient, wherein the PPG signal includes a plurality of PPG features indicating the occurrence of a cardiac pulse;
• determine, using processing circuitry in communication with a memory, a plurality of pulse transit time (PTT) intervals, wherein a PTT interval of the plurality of PTT intervals corresponds to each depolarization of the plurality of depolarizations, wherein each PTT interval of the plurality of PTT intervals represents an amount of time between a respective depolarization of the set of depolarizations and a PPG feature of the plurality of PPG features that occurs after the respective depolarization and before a subsequent depolarization of the plurality of depolarizations;
• determine, based on the accelerometer signal, a posture of the patient from a plurality of postures corresponding to each PTT interval of the plurality of PTT intervals;
• associate each PTT interval of the plurality of PTT intervals with one or more classifications, wherein the one or more classifications corresponding to each PTT interval of the plurality of PTT intervals indicate the posture of the patient corresponding to the respective PTT interval;
• select, from the plurality of PTT intervals, a set of PTT intervals based on the one or more associated classifications for each PTT interval of the plurality of PTT intervals, wherein each PTT interval of the set of PTT intervals is associated with a classification of the one or more classifications indicating at least one posture of a set of postures;
• and
• monitor, based on the selected set of PTT intervals, a patient condition.