The Effect of Cardiac Resynchronization Therapy on Left Ventricular Diastolic Function Assessed with Speckle-Tracking Echocardiography

AIMS: Changes in left ventricular (LV) diastolic function after cardiac resynchronization therapy (CRT) in relation to LV reverse remodelling and heart failure aetiology have not been extensively characterized. The aims of the study were to evaluate changes in LV diastolic function with speckle-tracking echocardiography in relation to: (i) cardiac resynchronization therapy response (LV remodelling) and (ii) heart failure aetiology. METHODS AND RESULTS: A total of 192 heart failure patients undergoing CRT implantation were evaluated. Speckle-tracking echocardiography was performed before and 6 months after implantation and reliable analysis was obtained in 188 patients. Left ventricular diastolic function was assessed by measuring diastolic strain rate during the isovolumic relaxation period (SR(IVR)) and by calculating the ratio of peak transmitral E-wave to SR(IVR) (E/SR(IVR)). Changes in LV diastolic parameters were evaluated in responders and non-responders and in patients with ischaemic and non-ischaemic cardiomyopathy. Response to CRT was defined as ≥15% reduction in LV end-systolic volume at 6 months follow-up. One-hundred and nine patients (58%) were defined as responders. Significant improvements in LV diastolic performance were observed in responders with improvement in SR(IVR) (from 0.14 ± 0.08 to 0.18 ± 0.12 s(-1), P= 0.001) and E/SR(IVR) (from 834 ± 840 to 641 ± 612, P= 0.04). In addition, LV relaxation improved in patients with non-ischaemic aetiology (SR(IVR): from 0.15 ± 0.08 to 0.19 ± 0.13 s(-1), P= 0.004). In contrast, LV relaxation did not improve in non-responders and in patients with ischaemic heart disease. CONCLUSIONS: Novel diastolic strain rate indices are useful for evaluating changes in LV diastolic function after CRT. Improvement in diastolic function was only observed in responders to CRT and patients with non-ischaemic aetiology.