Figure 3.

NKA and NCX reductions can both enhance SAM automaticity and impair pacemaking activity depending on the degree of block. (A) Bar graph showing the relative contribution of NKA, NCX, I_Na1.1, I_Na1.5, I_st, I_NaB, and I_f to total Na⁺ influx and removal during a beat cycle in the optimized murine SAM model. (B) Average FR upon simulation of various extents of NKA block. Insets show voltage traces obtained simulating 40%, 60%, and 70% block. (C) Average FR upon simulation of various extents of NCX block. Insets show voltage traces obtained simulating 50%, 75%, and 80% block. Thin gray traces in insets correspond to the voltage traces simulated in the absence of the block.