RR interval:Time:Stdy^mean:Heart:Qn:EKG
rr interval:time:stdy^mean:heart:qn:ekg
RR interval:Time:Duration of the study^Mean of all of the values observed on the interval:Heart:Quantitative:EKG
rr interval:time:duration of the study^mean of all of the values observed on the interval:heart:quantitative:ekg