Abstract 14250: Innovative Model-Based Algorithm for Non-Invasive Estimation of Pressure-Volume Loops in Patients With Cardiogenic Shock

Abstract

Introduction: Cardiogenic shock (CS) pathophysiology may be well explained through the left ventricular pressure-volume (PV) loops. Hypothesis: We developed an innovative model-based algorithm to derive non-invasive left ventricular PV loops and we assessed its ability to provide information in CS patients. Methods: We conceived and implemented a simple, intuitive and practical model-based algorithm for the non-invasive left ventricular PV loop diagram visualization and analysis. This model is based on the quantitative numerical calculation of the product of two time-varying curves, namely the LV volume V(t) multiplied by the time varying LV elastance function, in order to obtain the time varying LV pressure curve, according to the well-known relation: P(t) = E(t) * V(t) [formula F1] [Seeman et al. 2019]. The algorithm works as follows: 1) Input parameters: HR, EDV, ESV, Estimated LV elastance value for healthy (control) and for pathologic subjects. 2) Picked qualitative illustrations exhibiting time-varying dynamics of:a. Normal LV Elastance b. Normal LV Volume 3) Digitized, appropriately scaled, and adapted to input, curves in step (2).4) P(t) obtained by applying formula (F1) in Excel spreadsheet.5) Construction of the PV Loop diagram in Excel spreadsheet. Results: To test the algorithm, non-invasive input parameters were collected in a patient with CS due to acute myocarditis and in a normal subject. In the CS patient, HR, ESV, EDV were 83bpm, 228 ml and 200 ml, respectively; while in the normal subject, they resulted as 86 bpm, 110 ml, and 45 ml, respectively. In the CS patient, the non-invasive derived PV diagram was significantly different from that assessed in the control subject and exhibited an abrupt reduction of ventricular contractility. Conclusions: This novel model-based algorithm provides reliable non-invasive left ventricular PV diagrams in CS patients.