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.