Heart rate correction based on 'universal' regression equation--erroneous conclusions when studying cardiac...

Area of Science:

• Cardiovascular Physiology
• Biomedical Engineering
• Clinical Diagnostics

Background:

• Heart rate correction is commonly applied to mechanical cardiac function parameters to account for heart rate variability.
• Universal regression equations are often employed for this purpose, assuming a consistent relationship between heart rate and cardiac function.
• The validity of these universal equations, particularly the Weissler regression equations for systolic time intervals, needs critical evaluation.

Purpose of the Study:

• To investigate potential errors introduced by using a 'universal' regression equation for heart rate correction of mechanical cardiac function parameters.
• To assess the impact of such rate correction on the physiological interpretation of cardiac function during various stress provocations.

Main Methods:

• Mechanical cardiac function parameters, specifically systolic time intervals, were measured.
• Rate correction was applied using Weissler regression equations.
• Measurements were conducted during isometric handgrip, orthostatic, Valsalva, and cold pressor tests.

Main Results:

• Rate correction resulted in a significant correlation between changes in heart rate and the rate-corrected systolic time interval in most measurements.
• This induced dependence between heart rate and the corrected parameter was observed across different stress provocation tests.
• The introduced correlation complicates the physiological interpretation of the measured cardiac function parameters.

Conclusions:

• The use of 'universal' regression equations for heart rate correction can create artificial dependencies, hindering accurate physiological interpretation.
• It is recommended to avoid rate correction using universal regression equations for mechanical cardiac function parameters during stress provocations.
• Alternative methods or uncorrected parameters should be considered for more reliable assessment of cardiac function under stress.