Differential risk for arrhythmic events among Mutation Carriers (MCs) according to resting heart rate off- βB and QTc. The dashed horizontal line represents the predefined cut-off for QTc (≤ or > 500 ms) whereas the dashed vertical line corresponds to the first tertile (≤ 60 bpm) of the heart rate values distribution. It is evident that in the group of patients with a QTc ≤ 500 ms those the first tertile (heart rate ≤ 60 bpm) were less frequently symptomatic compared to MCs in the other two tertiles (OR 0.19, 95%CI 0.04–0.79, p = 0.023). This figure also provides evidence that a QTc > 500 ms represents a more severe arrhythmogenic substrate in our population based on the fact that 15 of 16 (94%) MCs with a QTc > 500 ms were symptomatic. (Reprinted from ref.  with permission from Lippincott Williams and Wilkins).