Prolongation of APD and slow conduction in hearts of SCD mice. (A) Representative AP traces from CTR (black) and SCD (red) hearts. (B) Activation maps from CTR (left) and SCD hearts (right). The center of the LV was stimulated with a concentric bipolar electrode to measure longitudinal conduction velocity (CV_L) and transverse conduction velocity (CV_T). (C-D) CV_L of SCD hearts was slower than that for CTR hearts (0.75 ± 0.11 ms in CTR vs 0.58 ± 0.07 ms in SCD mice; P = .002), and CV_T was not significantly different between CTR and SCD hearts (0.37 ± 0.056 ms in CTR vs 0.35 ± 0.05 ms in SCD mice; P = .51). *P < .05. Error bars represent standard error. (E) APD maps from the LV in CTR and SCD hearts. (F) APDs of SCD hearts were prolonged (60.4 ± 10.7 ms in CTR vs 74.5 ± 8.4 ms in SCD; P = .006). (G) Spatial dispersion of APDs was also increased in SCD hearts (18.3 ± 4.8 ms in CTR vs 27.6 ± 10.9 ms in SCD; P = .025) (n = 10 for CTR group; n = 9 for SCD group). Median values displayed with whiskers using the Tukey method. CL, cycle length.