Modeling the Rate of Premature Ventricular Contractions and its Response to Lidocaine Infusion

The rate of premature ventricular contractions (PVC rate) and the dynamics of its response to the intravenous infusion of the antiarrhythmic drug lidocaine was modeled to facilitate the design of a closed-loop drug infusion system. An autoregressive moving average model structure with the lidocaine infusion rate as an exogenous input (ARMAX structure) was used. System identification experiments were performed using a canine model of myocardial infarction. The drug infusion rate was varied using a pseudorandom binary sequence (PRBS) test input to excite the system about an operating point established by an exponential infusion regimen. PVC´s were detected in real time with a correlation technique. Model parameters were estimated in an offline data analysis. First-order models provided an adequate representation of the PVC rate in eight of ten runs. A second-order model was validated for two runs.