Hybrid logistic function characterization of left ventricular pressure-time curve in left heart catheterization

BACKGROUND: The left ventricular (LV ) pressure-time curve (PTC) during one cardiac cycle in left heart catheterization includes much useful information for evaluating LV inotropism and lusitropism. Nonlinear regression analysis using the least-squares method is a valuable tool for elucidating the mechanism, summarizing information, eliminating noise, allowing speculation regarding unmeasured data, and separating the effects of multiple factors. We proposed that the isovolumic LV PTCs in some animal experiments have been presented with a hybrid logistic (HL) function which is the difference between two sigmoid logistic functions. In the present study, we applied some types of the HL function models for the clinical field and investigated which type of the HL function equation could precisely fit the LV PTCs in the human hearts. METHODS: The 30 LV PTCs at 1 ms interval during one cardiac cycle in left heart catheterization in 10 patients were recorded and fitted with the four kinds of the HL function equations using the least-squares method; CONCLUSIONS: The HL function model with seven parameters precisely fits the LV PTCs in the human hearts. The seven HL function parameters can reliably characterize the LV pressure and time course for evaluation of cardiac inotropism and lusitropism regardless of species. (Equation Presented).