Triphasic and quadriphasic waveforms are superior to biphasic waveforms for synchronized beating of cardiomyocytes.

Background And Purpose: Within pacemaker research few attempts have been made to find an optimal waveform phase sequence that synchronizes beating of cardiomyocytes at an electrode. Multielectrode arrays (MEAs) offer electrophysiological screening of cardiomyocytes serving as a system for preliminary screening of pacing waveform design.

Materials And Methods: The HL-1 cell line was cultured in MEAs until confluence and stimulated with biphasic, triphasic, and quadriphasic waveforms. The amplitudes required for synchronized beating of the cells were determined.

Results: Triphasic and quadriphasic waveforms were more efficient in eliciting synchronized beating of the HL-1 cells compared with the biphasic waveform because it allows significant reductions in synchronizing voltage amplitudes and reductions in supplied stimulus.

Conclusion: The MEA system allows for a straightforward manner to investigate effects of waveform design on synchronized beating in cardiomyocytes in vitro. Increased number of phase changes in a pacing waveform seems to be the major reason for the reduction in synchronizing amplitudes.