A method for determining high-resolution activation time delays in unipolar cardiac mapping

Area of Science:

• Biomedical Engineering
• Cardiac Electrophysiology
• Signal Processing

Background:

• Accurate measurement of activation time delays is crucial for understanding cardiac electrical propagation.
• Existing methods for determining these delays in unipolar cardiac mapping data have limitations in resolution and accuracy.

Purpose of the Study:

• To present a novel method for determining activation time delays in unipolar cardiac mapping data with resolution significantly smaller than the sampling interval.
• To compare the accuracy and precision of this new method against a conventional criterion.

Main Methods:

• Utilized filtered and differentiated electrograms from simultaneous endocardial/epicardial recordings in swine right atrium.
• Computed the Hilbert transform of the cross-correlation of electrogram pairs.
• Identified activation time delay via the negative-to-positive zero crossing of the Hilbert transform output.

Main Results:

• The Hilbert transform method successfully determined activation time delays with high resolution.
• A representative transmural activation time delay of 0.71 +/- 0.06 ms was measured.
• The Hilbert transform method demonstrated significantly smaller standard deviations compared to the maximum negative slope criterion, indicating improved accuracy.

Conclusions:

• The Hilbert transform of cross-correlation provides a robust and accurate method for estimating activation time delays in cardiac mapping.
• This technique offers superior precision over the maximum negative slope criterion for analyzing cardiac electrical signals.