Use of a comprehensive numerical model to improve biventricular pacemaker temporization in patients affected by heart failure undergoing to CRT-D therapy.

Cardiac resynchronization therapy by biventricular pacemaker/ICD implantation is a validated therapy for patients affected by heart failure with asynchrony of ventricular contraction. Considering the large number of parameters which play a role in cardiac resynchronization therapy, a comprehensive numerical model of cardiocirculatory system could be a useful tool to support clinical decisions. A variable elastance model of ventricles was updated to model the interventricular septum and to simulate the interventricular and the intraventricular desynchrony, and the effect of the biventricular stimulation. In addition, a numerical model of the biventricular pacemaker, which drives the beginning of the heart chambers and interventricular septum contraction, was also developed. In order to validate the model, five patients affected by dilated cardiomyopathy were analysed by echocardiography and electrocardiography before implantation, 24 h and 3 months after the implantation. The developed numerical model permits to reproduce clinical data and to estimate the trend of parameters that are difficult to measure (i.e. left ventricular systolic elastance). Furthermore, the model permits to study the effect of different biventricular pacemaker temporizations on hemodynamic variables.