Parthiban, Preethy2020-11-172020-11-172020-09https://hdl.handle.net/11299/217118University of Minnesota M.S. thesis. 2020. Major: Biomedical Engineering. Advisor: Alena Talkachova. 1 computer file (PDF); 56 pages.Cardiac alternans, beat-to-beat alternations in action potential duration (APD), is a precursor to fatal arrhythmias such as ventricular fibrillation (VF). Previous research has shown that voltage driven alternans can be suppressed by application of constant diastolic interval (DI) pacing protocol. However, the effect of constant-DI pacing on cardiac cell dynamics and its interaction with the intracellular calcium cycle remains to be determined. Therefore, we aimed to examine the effects of constant-DI pacing on the dynamical behavior of isolated cardiac myocytes along with the influence of voltage-calcium (V-Ca) coupling on these changes. Cardiac cell dynamics were analyzed in a non-linear neighborhood close to the bifurcation point using a hybrid pacing protocol, a combination of periodic and constant-DI pacing. We demonstrated that in a small region beneath the bifurcation point constant-DI pacing caused the cardiac cell to remain alternans-free after switching to the constant-BCL pacing, thus introducing a region of bistability (RB). Strong V-Ca coupling increased the size of the RB. Overall, our findings demonstrate that experimental constant-DI pacing on cardiac cells with strong V-Ca strength may induce permanent changes to cardiac cell dynamics increasing the utility of constant-DI pacing.enAction potentialAlternansArrhythmiasConstant diastolic intervalHeartPacemakerThesis or Dissertation