Fig. 2.

Electrophysiological characterization of cardiac optogenetics manipulations using the 473-nm laser in vivo. (a) Blue light pacing via illumination of different heart regions (blue line: 473 nm, 20 ms, 8 Hz, 0.96 mW/mm²; black line: ECG; RA: right atrium; LV: left ventricle; RV: right ventricle). (b-e) ECG parameters before, during, and after illumination of the right ventricle. QRS duration: light on, 32.67 ± 4.93 vs. before illumination, 19.08 ± 1.72, and vs. after illumination, 19.50 ± 1.96 in ms; PR interval: before illumination, 57.28 ± 3.59 vs. after illumination, 56.94 ± 4.53, in ms; QRS duration: before illumination, 19.08 ± 1.72, vs. after illumination, 19.50 ± 1.96 in ms; QT interval: before illumination, 69.11 ± 14.86 vs. after illumination, 71.64 ± 15.79 in ms; n = 6, The data are presented as the mean ± SEM. ****P < 0.0001; NS, P > 0.05; one-way ANOVA/Bonferroni (b, d, e) and paired t-test (c).