Surface ECG measurements. (A) Representative raw QT interval of baseline heart rate from surface ECG of CTRL and cRadKO. Scale bar, 0.5 mV, 50 ms. (B) Raw QT interval (ms) is not significantly different (P = 0.16). (C) QTc (ms) is not significantly different (P = 0.14). (D) Baseline R-R interval (ms) is not significantly different (P = 0.97). (E) Intrinsic R-R interval (ms) is not significantly different (P = 0.48) CTRL: n = 6 mice; cRadKO: n = 7 mice. P values calculated using Student’s unpaired t test for B–E. Data in B–E are presented as mean ± SEM values.