.25 + 0.10 vs 0.20 + 0.06, P = 0.023). Moreover, the slopes of QTend/RR and QTapex/RR of high-risk patients were significantly steeper than those of control subjects while no significant differences were found among low-risk HCM patients and control subjects and only QTe/RR of high-risk patients was significantly different between low- and high-risk HCM patients.