Echocardiographic Effects of Changing Atrioventricular Delay in Cardiac Resynchronization Therapy Based on Displacement

Background

In studies showing benefits of cardiac resynchronization therapy (CRT), individual atrioventricular (AV) delays have been optimized using echocardiography. However, the method for AV delay optimization remains controversial.

Methods

In 100 consecutive patients with CRT device implantation, AV delay was optimized using echocardiography. The optimal AV delay was determined by changing the interval in 20-ms increments while measuring displacement in 6 basal left ventricular segments (averaged and reported as left ventricular displacement [D_LV]) and other echocardiographic measures.

Results

A single optimal AV delay existed for each patient, and the associated highest D_LV corresponded with the maximal velocity-time integral (VTI) in the left ventricular outflow tract (VTI_LVOT) and the E/e′ ratio. Significant increases in D_LV and the VTI_LVOT from before to after implantation with standard settings and from standard to optimal AV delay by displacement were found. Diastolic filling time corresponded poorly with D_LV and the VTI_LVOT.

Conclusion

Individual optimal AV delay programming provides significant improvement in left ventricular performance and hemodynamics. Displacement analysis and the VTI_LVOT are interchangeable, whereas diastolic filling time cannot be recommended.

Keywords: AV delay, CRT optimization, Echocardiographic displacement

Abbreviations: AV, Atrioventricular, CRT, Cardiac resynchronization therapy, DFT, Diastolic filling time, D_LV, Left ventricular displacement, D_RV, Right ventricular displacement, LV, Left ventricular, LVEF, Left ventricular ejection fraction, RV, Right ventricular, VTI, Velocity-time integral, VTI_LVOT, Velocity-time integral in the left ventricular outflow tract