| Description |
This study introduces a pipeline for the temporal dilation of canine cardiac signals following registration to human torsos. Performing registration of data attained from canine electrophysiology studies to human torso geometries allows for a larger database for the investigation of human-like arrhythmias that cannot be readily obtained otherwise. However, during registration, the canine cardiac signals must be adjusted to correct spatially dependent aspects of propagation, such as conduction velocity (CV), that are influenced by increased heart size. We refer to this correction process as "temporal dilation'' as it includes resampling of the cardiac signals. We acquired 10 canine cardiac recordings from electrodes built into socks that covered the epicardial surface of the ventricles. The sock geometries were registered to two human torsos. From this spatial transform, we calculated both global and local scaling factors needed to adjust the time signals. Signals were then dilated with both scaling types using linear and nonlinear techniques. The linear method homogeneously dilated the entire signal and the nonlinear technique dilated segments of the signals outside the QRS and T wave. Dilated cardiac signals were validated by comparison of calculated values of CV, total activation time (TAT), and activation recovery interval (ARI). Activation maps also served as a means of qualitative comparison. The observed ECG metrics of canine cardiac signals after temporal dilation using global scaling closely resembled those from human recordings in terms of CV, ARI, and TAT. Temporally dilated signals using local scaling, in contrast, caused the observed ECG metrics to no longer remain within a physiologically relevant range. A realistic activation pattern was maintained after temporal dilation using global scaling. Though temporal dilation using locally calculated scaling factors did not result in physiologically relevant cardiac signals to humans, homogenous temporal dilation could be used to correct the spatially dependent aspects of propagation after geometric registration of canine hearts to human torso geometries. Homogenous temporal dilation, therefore, is a technique that can be used to generate human-like cardiac signals useful for validation of devices used to diagnose, monitor, or intervene in cases of cardiac arrhythmias. |
