A comparison of two interpolation methods for estimation of electrograms within a two-dimensional epicardial plaque

Epicardial mapping has made more detailed electrical analysis of cardiac activation feasible. Effective recording sites can be increased by interpolating between existing measurements. In this study canine electrograms recorded from an epicardial electrode plague were estimated using linear and cubic interpolation methods for comparison. Unipolar electrograms from a 112 (7×16) electrode plague were recorded. Three different pacing protocols as well as a non-paced sequence were used for analysis. Twenty-one of the 112 activation patterns were estimated using both linear and cubic interpolation techniques from combinations of the surrounding electrodes. The correlation coefficient was used to compare the interpolated and actual electrograms. Linear averaging showed a superior performance over cubic spline interpolation (overall p<.05) and can be achieved with simple calculations allowing for multiple site interpolations to be computed easily