Vulnerability to reentry, and drift, stability and breakdown of spiral waves in a linear gradient of GK in a Luo-Rudy 1 virtual ventricular tissue

The vulnerable window in a heterogeneous virtual LRI cardiac tissue, with a linear gradient in G(K), is wider when following propagation down the gradient, towards tissue with longer action potential duration, than when following propagation up the gradient. Spiral wave solutions in a uniform linear gradient in G(K) drift, with a velocity component along the gradient of the order of mm/s, towards tissue with a longer APD.