ECG-based beat-to-beat assessment of AV node conduction properties during AF.

Area of Science:

• Cardiology
• Biomedical Engineering
• Computational Physiology

Background:

• The atrioventricular (AV) node regulates heart rate during atrial fibrillation (AF).
• Beat-to-beat variations in AV node refractory period and conduction delay are influenced by the autonomic nervous system (ANS).
• These variations have been difficult to assess during AF, limiting personalized diagnosis and treatment.

Purpose of the Study:

• To develop and validate a methodology for estimating AV nodal conduction properties with beat-to-beat resolution during AF.
• To assess the impact of the ANS on AV node function during AF using this methodology.

Main Methods:

• A network model of the AV node was combined with a particle filter and smoothing algorithm.
• The methodology was tested using simulated data and synchronized electrogram (EGM) and electrocardiogram (ECG) recordings from AF patients.
• Changes in AV node properties were analyzed during a tilt test protocol in 21 AF patients.

Main Results:

• The method accurately estimated AV nodal refractory period and conduction delay, with mean absolute errors as low as 67 ± 10 ms.
• Estimations based on EGM recordings showed lower errors than those based on ECG.
• A decrease in conduction delay and refractory period was observed during head-up tilt, consistent with sympathetic ANS activation.

Conclusions:

• Beat-to-beat estimation of AV nodal conduction properties from ECG during AF is feasible.
• The developed methodology provides insights into ANS-induced modulation of AV node function in AF.
• This approach holds potential for improved diagnosis, prognosis, and personalized treatment strategies in AF.