Assessment of the maximum frequency components and digital sampling of cardiac Purkinje fiber action potentials

An investigation was made into a reasonable continuous sampling frequency for cardiac Purkinje fiber action potentials. Under the assumption that digital sampling will effectively capture frequency components up to half the sampling rate, action potential records made at 25 kHz were low-pass filtered at various cutoff frequencies. The filtered and unfiltered records were compared by calculating V̇ max to determine the effects of progressive loss of high frequency components. It was determined that sampling at 13 kHz is adequate for action potentials with upstroke velocities up to 500 V/sec, and that estimation of V̇ max in excess of 800 V/sec is possible.