Evaluating left ventricular diastolic function and chamber stiffness in heart failure: the impact of cardiac resynchronisation therapy on diastolic mechanics

Sibel Ҫatalkaya, Berat Uğuz

Abstract

Background: Cardiac resynchronisation therapy (CRT) is a standard treatment for heart failure patients with ventricular conduction delay. While its benefits on left ventricular (LV) systolic function are well-established, the effects on LV diastolic mechanics remain controversial. This study aimed to investigate the interactions between CRT therapy, LV diastolic function, and LV chamber stiffness.
Methods: We evaluated 71 heart failure patients before and six months after CRT using two-dimensional echocardiography. LV volumes, ejection fractions (EF), and diastolic function parameters, including transmitral filling indices, tissue Doppler, and the E/e' ratio, were measured. The LV stiffness index (LV-SI) was calculated using the formula (E/ e' lateral) / end-diastolic volume [EDV]). CRT response was defined as a > 15% reduction in LV end-systolic volume.
Results: Among CRT responders (67.6%), a mean reduction of 26.3% in LV end-systolic volume and a median EF improvement to 40% were observed. Diastolic function improved significantly (E-wave velocity 20.9%, E/A ratio ↓16.5%, and E/e' ratio ↓32.7% medial and $34.9% lateral; p < 0.001 for all values). The LV stiffness index decreased by 19.48% (p < 0.001). Non-responders showed no significant changes. Baseline parameters for both pulsed-wave and tissue Doppler measurements, as well as LV-SI, showed no significant differences between responders and non- responders.
Conclusion: This study demonstrates that CRT responders exhibited significant improvements in diastolic function, including measurements of LV filling pressure and active relaxation, as well as a reduction in LV stiffness. Additionally, LV stiffness and diastolic parameters do not appear to influence the response to CRT.