Responses of peak ear-pulse derivative to changing left ventricular function

Area of Science:

• Cardiovascular Physiology
• Biomedical Engineering
• Diagnostic Technology

Background:

• The arterial pressure derivative (dP/dt) is a key indicator of cardiac function.
• A non-invasive, reliable analog for monitoring cardiac output and ventricular function is needed.
• The ear densitograph displacement pulse derivative (dD/dtear) offers a potential solution.

Purpose of the Study:

• To evaluate the ear densitograph displacement pulse derivative (dD/dtear) as a non-invasive measure of cardiac function.
• To assess the reliability of dD/dtear in monitoring ventricular performance under varying conditions.
• To compare dD/dtear with established echocardiographic parameters.

Main Methods:

• Utilized the ear densitograph displacement pulse derivative (dD/dtear) transducer.
• Employed atrial fibrillation as a model of functional variability in eight subjects.
• Correlated peak dD/dtear (P) with echocardiographic measures (stroke volume, ejection fraction, ejection rate, velocity of circumferential fiber shortening) and timing intervals (cycle length, preejection period (PEP), left ventricular ejection time (LVET)).

Main Results:

• Peak dD/dtear (P) closely tracked stroke volume, ejection fraction, ejection rate, and velocity of circumferential fiber shortening.
• Minor deviations were observed in subjects with mitral regurgitation or paradoxical septal movement.
• Excellent correlations were found between P and cycle length, PEP, LVET, and PEP/LVET ratios across all subjects.

Conclusions:

• The ear densitograph displacement pulse derivative (dD/dtear) demonstrates technical reliability and uniform application.
• dD/dtear is a valuable tool for intrasubject monitoring of changing ventricular function.
• The method shows promise as a non-invasive alternative for assessing cardiac performance.