A Simplified Approach for Simultaneous Measurements of Wavefront Velocity and Curvature in the Heart Using Activation
Nachaat Mazeh1, David E Haines2, Matthew W Kay3
1Department of Cardiovascular Medicine, Beaumont Health System, Royal Oak, MI, USA.
Insights
A new computational model accurately determines wave front speed and curvature in cardiac tissue using arrival times at multiple sites. This simplified approach aids in understanding and mapping arrhythmias like fibrillation.
Area of Science:
- Computational electrophysiology
- Cardiac electrophysiology
- Medical device technology
Background:
- Wave front velocity and curvature are critical for electrical activity propagation in cardiac tissue.
- Existing computational models struggle to simultaneously determine these wave front properties.
- Accurate characterization is vital for understanding cardiac arrhythmias like fibrillation.
Purpose of the Study:
- To develop a simplified computational model for simultaneously determining wave front speed, direction, and radius of curvature (ROC).
- To validate the model's accuracy against established methods under various conditions.
- To assess the model's applicability for clinical arrhythmia analysis.
Main Methods:
- The model utilizes arrival times at four or five recording sites to calculate wave front parameters.
- Calculations are based on differences in arrival times and distances between recording sites.
- The model was tested under isotropic and anisotropic conduction conditions, including reentry.
Main Results:
- Excellent correlation was found between measured ROC and distance from the stimulus (r=0.9043).
- High correlation (r=0.998) was observed for conduction velocity compared to an empirical method.
- The simplified model showed insignificant measurement errors and maintained accuracy across different wave front morphologies.
Conclusions:
- The developed simplified model accurately and efficiently determines cardiac wave front properties.
- It offers a viable alternative to more computationally demanding methods, with accuracy maintained for ε between 0.001 and 0.5.
- This model has potential applications in studying arrhythmia mechanisms, rotor mapping, and clinical diagnostics.
Abstract:
The velocity and curvature of a wave front are important factors governing the propagation of electrical activity through cardiac tissue, particularly during heart arrhythmias of clinical importance such as fibrillation. Presently, no simple computational model exists to determine these values simultaneously. The proposed model uses the arrival times at four or five sites to determine the wave front speed (v), direction (θ), and radius of curvature (ROC) (r0). If the arrival times are measured, then v, θ, and r0 can be found from differences in arrival times and the distance between these sites. During isotropic conduction, we found good correlation between measured values of the ROC r0 and the distance from the unipolar stimulus (r = 0.9043 and p < 0.0001). The conduction velocity (m/s) was correlated (r = 0.998, p < 0.0001) using our method (mean = 0.2403, SD = 0.0533) and an empirical method (mean = 0.2352, SD = 0.0560). The model was applied to a condition of anisotropy and a complex case of reentry with a high voltage extra stimulus. Again, results show good correlation between our simplified approach and established methods for multiple wavefront morphologies. In conclusion, insignificant measurement errors were observed between this simplified approach and an approach that was more computationally demanding. Accuracy was maintained when the requirement that ε (ε = b/r0, ratio of recording site spacing over wave fronts ROC) was between 0.001 and 0.5. The present simplified model can be applied to a variety of clinical conditions to predict behavior of planar, elliptical, and reentrant wave fronts. It may be used to study the genesis and propagation of rotors in human arrhythmias and could lead to rotor mapping using low density endocardial recording electrodes.
