Analysis of dynamic changes in ECG signals during optical mapping by dynamic time warping

Voltage-sensitive dyes (VSDs) are used in touch-less recording of electrical activity from animal hearts. Previously, VSDs has been successfully used in myocardial ischemia studies. However, our previous Langendorff perfused heart experiments have suggested changes in ECG signals in time and time-frequency domain caused by application of VSD during optical mapping. Detailed analysis of changes is needed to reveal impact to particular fractions of a heart cycle. Dynamic time warping (DTW) is applied to P-Q segments, QRS complexes, and ST-T segments of selected consecutive heart cycles in each experiment period. An optimal path resulting from DTW based on minimum distance between the control segments (before the application of VSD) and segments recorded in next two experiment steps is computed