Modeling cardiac ion channel conductivity: model fitting via simulation

Describes a Markov state model for a cloned potassium channel of the human heart (I/sub K/spl nu/LQT1/). The parameters of the model are determined by a least-squares fit of predicted vs. measured data. The fitting process is achieved by using the "SPSA" optimizer to sequentially choose trial values of the parameters. At each choice of parameter value, a loss function is computed by simulating the action of the channel at that trial parameter value. When the optimizer has converged, the parameter value represents the best fit.