“…Detector algorithms can be based on heuristic derivative equations that identify discrete measurements or adaptive thresholds, for example, the increasing edge of the R-peak (Bonner et al, 1972;Pryor et al, 1969). Alternatively, they can be based on complex statistical algorithms that use linear or nonlinear filters, different transformations, or discriminant function analysis (Köhler et al, 2003;Pan and Tompkins, 1985;Romhilt and Estes, 1968). Interpolation algorithms, to replace missing or abnormal heart period series, include proximal, piecewise cubic Hermite, non-linear predictive interpolation, linear, and cubic spline interpolations (Kim et al, 2009;Lippman et al, 1994;Malik and Camm, 1995).…”