The evolution of hemodynamic force parameters after cardiac resynchronization

Abstract

Abstract Funding Acknowledgements Type of funding sources: None. Background A new mathematical model allows calculation of hemodynamic forces (HDF) from routine transthoracic echocardiographic images. In large cohorts, the evolution of HDF parameters in patients after onset of cardiac resynchronization therapy (CRT) has not been investigated. Purpose To compare HDF parameters at baseline versus six months follow-up after CRT implantation in patients with non-ischemic cardiomyopathy. Methods Patients with LV ejection fraction (LVEF) ≤35%, QRS duration ≥130 ms and left bundle branch block were included. In the complete heart cycle, the following HDF parameters were calculated: apical-basal strength (AB strength), lateral-septal strength (LS strength), the ratio of LS strength to AB strength (LS-AB ratio) and the dominant angle of HDF (angle) (Figure 1). In the systolic thrust, apical-basal impulse (AB impulse) and the angle were measured (Figure 1). The measurements are presented as percentages, normalized for left ventricular volume and adjusted for fluid density and gravity acceleration. The measurements were acquired at baseline and six months after CRT implantation. Results 196 patients were included (mean age 64 ± 11 years, 62% male). Clinical and echocardiographic characteristics were acquired, as well as HDF parameters at baseline and after six months (Table 1). After six months a significant improvement occurred in clinical parameters (New York Heart Association class, Quality of Life and 6-minute walking distance) with significant reverse LV remodeling (reduction in left ventricular and left atrial volumes with increased LVEF and global longitudinal strain). Moreover, a significant change in the magnitude of apical-basal force, represented in the AB strength and AB impulse and in the orientation of force, represented as the ratio and the angle of HDF were observed. Conclusion The evaluation of HDF parameters after CRT implantation shows an increase in magnitude of force and a change in orientation of force. This new tool provides insight in changes of fluid dynamics after CRT implantation and may contribute to better understand the benefit of CRT.