Abstract 13654: Can a Novel Earbud Technology Detect Severe Aortic Stenosis? Modernizing the Wiggers Diagram Through Infrasonic Hemodynography Synchronized With Echocardiography and Cardiac Catheterization

Abstract

Introduction: Severe aortic stenosis (AS) produces a typical systolic ejection sound detected by clinical auscultation with a characteristic feature on Doppler echocardiography (ECHO) & hemodynamics at cardiac catheterization (CC). We propose a new assessment of AS through ‘infrasonic hemodynography’ (IH) - cardiovascular monitoring by infrasound (<20 Hz) measured by a novel digital device. To assess AS, we aim to compare IH to standard ECHO & CC measurements. Methods: We report an N-of-1 analysis from an ongoing prospective clinical trial to validate IH on cardiac function. A study subject with severe AS wore the IH ear-bud (MindMics, Figure A) & underwent simultaneous measurements with IH-ECHO & IH-CC-ECG, with IH waveforms (in-ear acoustic pressure in Pascals) synchronized (via cross-correlation), stacked (11 heart beats), & averaged over the QRS complex of the ECG. The QRS complex was then used as a reference to generate a quantitative Wiggers diagram, aligning IH & CC waveforms with the aortic valve on ECHO. Time of aortic valve opening (AVO) & closure (AVC) were determined from the ECHO image. The systole & diastole were assessed by creating Wiggers diagrams from the LV outflow & mitral valve inflow ECHO images. Results: The peak systolic pressure in CC occurred close to the AVC derived from ECHO (Figure B), as is typical of the delayed peak pressure in severe AS. This was captured in the IH waveform & visualized by overlaid LV & AO pressures simultaneously collected during CC (Figure C). Additionally, the blood pressure increase seen on CC in response to AVC (the dicrotic notch) was also delayed & aligned with the drop in flow & the start of the E wave on ECHO, consistent with severe AS, & detected on IH. Conclusions: We describe in-ear IH as a new method for non-invasive measurement of severe AS. Infrasound assessment of cardiac function represents a potentially important development to modernize the Wiggers Diagram & to detect valvular disease that is independent of ECHO & CC.