Systolic time intervals utilizing ear densitography. Advantages and reliability for stress testing.

Area of Science:

• Cardiovascular Physiology
• Biomedical Engineering

Background:

• Systolic time intervals (STIs) are crucial indicators of cardiac function.
• The carotid pulse curve is a traditional method for measuring STIs, but it can be invasive and technically demanding.
• Non-invasive methods for STI assessment are highly desirable.

Purpose of the Study:

• To evaluate the ear densitogram derivative as a non-invasive replacement for the carotid pulse curve in measuring systolic time intervals.
• To assess the reliability of the ear densitogram derivative under various cardiocirculatory conditions, including rest and stress.

Main Methods:

• Systolic time intervals were measured in 10 healthy volunteers.
• Measurements were taken using both the ear densitogram derivative and the carotid pulse curve.
• Data were collected at rest and during induced cardiocirculatory stress.

Main Results:

• The ear densitogram derivative demonstrated excellent agreement with the carotid pulse curve.
• High correlation coefficients were observed for both left ventricular ejection time (r = +0.98) and pre-ejection period (r = +0.98).
• The ear densitogram waveform proved to be stable and technically simple to acquire.

Conclusions:

• The ear densitogram derivative is a reliable and accurate non-invasive method for measuring systolic time intervals.
• This technique can be effectively used both at rest and during physiological stress, offering a practical alternative to the carotid pulse curve.