Abstract 16610: A New Left Ventricle Vortex Formation Time for Clinical Assessment of Diastolic Filling Efficiency Based on Direct Mechanical Ventricular-Vascular Coupling: Evaluation in Heart-Failure and Healthy Cohort

Abstract

Introduction: The mechanical coupling of the left ventricle (LV) and aorta creates the apical motion of the atrioventricular plane (AVP), resembling a piston-cylinder system, impacting early diastolic filling (J Am Heart Assoc. 2017;6:e004903). Furthermore, several clinical studies have suggested the vortex formation time (VFT) as an indicator of LV diastolic function (Eur. Heart J. Cardiovasc. Imaging. 2012;13(5):385-93). However, conflicting results exist in previous clinical studies, potentially due to deviations from the original fluid dynamics definition of VFT in a piston-in-cylinder setting. In this study, we propose a new VFT approach to assess LV diastolic filling performance based on direct mechanical ventricular-vascular coupling. Methods: Cardiac MRI was used on 69 healthy individuals and 19 heart failure (HF) patients. The clinical cohort (37% women) had a mean age of 46 [± 17.5] years and BMI of 24.8 [±4.5]. LV valvular diseases were excluded. VFT was assessed using the original L/D definition, where L represents ascending aortic recoil motion (piston displacement) and D represents the mitral valve orifice. Aortic displacement was measured on the three and four-chamber MRI scans by tracing the AVP. Mitral valve orifice was determined as the average of commissure distance (short-axis images) and the leaflet tip distance (three-chamber view). Results: The new VFT approach yielded a mean[± std.] of 4.73[±0.89] for the healthy group, and considerably lower values (3.24±0.83) for the patients with HF (figure 1). Conclusions: The proposed VFT based on the mechanical ventricular-vascular coupling and original fluid dynamic formulation, demonstrates a theoretical optimal value of approximately 4 in healthy individuals, while significantly lower in HF. This novel VFT has the potential to address existing discrepancies regarding the clinical significance of VFT and establish it as a promising indicator of left ventricular filling efficiency.