Related Experiment Videos
Nonsustained reentry following successive stimulation of cardiac tissue through a unipolar electrode
1Dept. of Physics & Astronomy: Vanderbilt University, Nashville, TN 37235, USA. roth@compsci.cas.vanderbilt.edu
Introduction:
Using numerical simulations, we predict that nonsustained reentry occurs following a strong, premature stimulus through a unipolar electrode.
Methods And Results:
Our simulations were based on the bidomain model of cardiac tissue, and the active membrane properties were represented by the Beeler-Reuter model. An outwardly propagating wavefront was excited by an initial stimulus (S1). A second stimulus (S2) was then applied through the same electrode. Nonsustained reentry or reentrant-like behavior followed the S2 stimulus for both cathodal and anodal stimulation, and were associated with "break" stimulation but not with "make" stimulation. The direction of spiral-wave rotation was reversed when the polarity of the stimulus was reversed. These complex dynamics occur only for a narrow window of S1-S2 intervals. During anodal S2 stimulation, two different modes of reentry exist. Our simulations also explain the "no response" phenomenon.
Conclusion:
Our mathematical model predicts that both anodal and cathodal unipolar S2 stimulation results in reentry. This behavior arises from an interaction of virtual anodes and cathodes surrounding the stimulating electrode.