DISTANT AND LOCAL EFFECTS ON UNIPOLAR EPICARDIAL RECORDINGS.

Determining the effect of distant events on unipolar epicardial recordings is an important clinical problem. In order to examine the local and distant components of unipolar waveforms, a surgical model has been used to electrically isolate the canine right ventricular free wall from the remainder of the heart. This model allowed independent pacing of the right and left ventricles. Asynchronous pacing was used to separate unipolar waveforms into local and distant components. The influence of distant potentials on the amplitude, slope, shape, and timing of local activations was investigated using synchronous pacing. The distant and local deflections recorded during asynchronous pacing were also used to reconstruct and simulate synchronous waveforms.