TY - JOUR
T1 - Characterizing Spatial Dynamics of Bifurcation to Alternans in Isolated Whole Rabbit Hearts Based on Alternate Pacing
AU - Kulkarni, Kanchan
AU - Visweswaran, Ramjay
AU - Zhao, Xiaopeng
AU - Tolkacheva, Elena G.
N1 - Publisher Copyright:
© 2015 Kanchan Kulkarni et al.
PY - 2015
Y1 - 2015
N2 - Sudden cardiac death instigated by ventricular fibrillation (VF) is the largest cause of natural death in the USA. Alternans, a beat-to-beat alternation in the action potential duration, has been implicated as being proarrhythmic. The onset of alternans is mediated via a bifurcation, which may occur through either a smooth or a border-collision mechanism. The objective of this study was to characterize the mechanism of bifurcation to alternans based on experiments in isolated whole rabbit hearts. High resolution optical mapping was performed and the electrical activity was recorded from the left ventricle (LV) epicardial surface of the heart. Each heart was paced using an "alternate pacing protocol," where the basic cycle length (BCL) was alternatively perturbed by ±δ. Local onset of alternans in the heart, BCL start, was measured in the absence of perturbations (δ = 0) and was defined as the BCL at which 10% of LV exhibited alternans. The influences of perturbation size were investigated at two BCLs: one prior to BCL start (BCL prior = BCL start + 2 0 ms) and one preceding BCL prior (BCL far = BCL start + 40 ms). Our results demonstrate significant spatial correlation of the region exhibiting alternans with smooth bifurcation characteristics, indicating that transition to alternans in isolated rabbit hearts occurs predominantly through smooth bifurcation.
AB - Sudden cardiac death instigated by ventricular fibrillation (VF) is the largest cause of natural death in the USA. Alternans, a beat-to-beat alternation in the action potential duration, has been implicated as being proarrhythmic. The onset of alternans is mediated via a bifurcation, which may occur through either a smooth or a border-collision mechanism. The objective of this study was to characterize the mechanism of bifurcation to alternans based on experiments in isolated whole rabbit hearts. High resolution optical mapping was performed and the electrical activity was recorded from the left ventricle (LV) epicardial surface of the heart. Each heart was paced using an "alternate pacing protocol," where the basic cycle length (BCL) was alternatively perturbed by ±δ. Local onset of alternans in the heart, BCL start, was measured in the absence of perturbations (δ = 0) and was defined as the BCL at which 10% of LV exhibited alternans. The influences of perturbation size were investigated at two BCLs: one prior to BCL start (BCL prior = BCL start + 2 0 ms) and one preceding BCL prior (BCL far = BCL start + 40 ms). Our results demonstrate significant spatial correlation of the region exhibiting alternans with smooth bifurcation characteristics, indicating that transition to alternans in isolated rabbit hearts occurs predominantly through smooth bifurcation.
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U2 - 10.1155/2015/170768
DO - 10.1155/2015/170768
M3 - Article
C2 - 26581885
AN - SCOPUS:84945220908
SN - 2314-6133
VL - 2015
JO - BioMed Research International
JF - BioMed Research International
M1 - 170768
ER -