Time domain indexes derived from HP and QT series in the BBoff-BBon protocol.

μHP  =  HP mean; σ2HP  =  HP variance; μQT  =  QT mean; σ2QT  =  QT variance; BBoff  =  off beta-blocker therapy; BBon  =  on beta-blocker therapy; ASYMP  =  asymptomatic group; SYMP  =  symptomatic group. Results are reported as mean ± standard deviation. The symbol * indicates p<0.05 within the same group (i.e. ASYMP or SYMP) versus BBoff. The symbol # indicates p<0.05 within the same therapy (i.e. BBoff or BBon) versus ASYMP subjects.