Effect of Cardiac Resynchronization Therapy on Left Ventricular Diastolic Function

Abstract

Aims: Cardiac Resynchronization Therapy (CRT) improves systolic performance in Heart Failure (HF). However, the effects of CRT on Left Ventricular (LV) diastolic function were variable and not fully understood. The aim of this study was to determine the effects of cardiac resynchronization therapy on LV diastolic filling pattern and the relation between the diastolic filling pattern and the response to CRT. Methods and Results: Twenty nine patients (mean age, 66 ± 8 years; 26 men; mean LV ejection fraction 25±7%) with severe HF were included. Measurements included LV volumes and Ejection Fraction (EF), pulsed-wave Doppler (PWD)-derived transmitral filling indices (E-and A-wave velocities, E/A ratio, Ewave deceleration time).Clinical responders were defined as survived patients with an improvement by one or more NYHA functional class, echocardiographic response to CRT was defined as a decline in LV end-systolic volume >15% during follow-up. In clinical responder group, both diastolic and systolic LV volumes decreased significantly (p=0.02 and p<0.001 respectively) and LVEF increased significantly (p=0.001) in 26 of 29 patients (89%) and were accompanied by reduction in mitral E-wave velocity and E/A ratio (both p<0.001), and increased A-wave velocity and Ewave deceleration time (p=0.03 and p<0.001). In echocardiographic responders, reverse remodelling (52%) was coupled to the improvement in LV diastolic function but diastolic filling pattern improved also in 42% in patients without reverse remodelling. Conclusion:Left ventricular diastolic indices after CRT improved in the clinical responder group, but there was no significant change in these indices among non-responders. CRT enhances diastolic filling patterns in both echocardiographic responder and nonresponder patients. This may be related to improvement in symptoms even in echocardiographic nonresponders who were clinical responders.