NEFL and Bradycardia: Baseline concentrations of pTau-181 were higher among subjects with bradycardia compared to both RHR 60–69 bpm and RHR ≥70 bpm (P < 0.05), while baseline concentrations of NFL were significantly higher among subjects with bradycardia compared to RHR 60–69 bpm only (P < 0.05, Table 1).