Non-invasive blood pressure monitoring with in-ear infrasonic hemodynography for preventative cardiovascular care.

Infrasonic Hemodynography (IH) captures low-frequency vibrations detected by in-ear microphones, offering a new approach to blood pressure monitoring. We report a strong correlation (r = 0.95) between IH waveforms and aortic blood pressure measurements obtained through cardiac catheterization (CC). Temporal analysis confirms the aortic origin of IH signals, with minimal differences in aortic valve opening timings between IH and CC (1.6 ± 12.1 ms), rejecting the hypothesis of peripheral origins. We test an approach to predict systolic (SBP) and diastolic (DBP) blood pressure from waveform morphology. The standard deviations of the differences between predicted and reference BP values averaged across 12 subjects is 4.1 mmHg (SBP) and 2.4 mmHg (DBP) for CC, and 5.8 mmHg (SBP) and 3.7 mmHg (DBP) for IH. These results demonstrate that BP information is encoded in the waveform shape dynamic. By capturing precise cardiovascular signals non-invasively, IH could enable earlier interventions and more personalized treatments.