Figure 6.

The panels in columns A, B and C show simulations of the effects of combining substantial I_Kr block together with I_Ca block on currents through the Na/Ca exchanger (I_NaCa), through L-type Ca²⁺ channels (I_CaL) and the ryanodine release current (I_rel), as well as the membrane potential (V) under conditions modelling (A) sham-operated hearts and (B and C) CHF hearts. Traces in A and B show results from a simple pore-blocker, whereas those in C denote the results for the state/voltage-dependent I_Ca block by verapamil. The reduction in Ca²⁺ cycling in the failing hearts is apparent as well as the benefit of verapamil state-dependent block over the other blocking type. Note the difference in the I_CaL dynamics during the EAD between the three traces.