Diverse characteristics in potential waveform of His-Purkinje system--experimental and simulation studies

Reflection to the body surface of the single beat-potentials of the His-Purkinje system (HPS) was analysed by a single beat recording of the epicardial HPS potentials from the Langendorff perfused canine heart and by the reconstruction of HPS potentials on the basis of the cable concept. Unipolar epicardial HPS potentials from 8 leads distributed equidistantly over the basal region of the ventricles were amplified by a high gain (120 dB) amplifiers with an active bandpass filter (40-2400 kHz). The waveform of these HPS potentials differed in each lead. The largest (42 +/- 8 microV, mean +/- SE, n = 5) of these HPS potentials, which was obtained from the anterior free wall of the right ventricle, was composed of two peaks: the initial slow- and positive-peak and the late sharp- and negative-peak. The former peak appeared 12 +/- 3 msec (mean +/- SE, n = 5) ahead of the spike of the His-bundle electrogram (HBE) recorded from the close bipolar electrodes which were attached intracavitally along the membrane portion of the His-bundle. The latter appeared in coincidence with the spike of HBE. The extracellular potentials generated by HPS excitation were calculated by assuming that the excitation proceeds along the three dimensionally reconstructed HPS. The simulated waveform was in agreement with those of the epicardial HPS potentials. Thus, the HPS potentials on the body surface may inscribe a diverse waveform as a reflection of the complexed architecture of the whole HPS.