Doppler echocardiographic methods for optimization of the atrioventricular delay during cardiac resynchronization therapy

Cardiac resynchronization therapy (CRT) is beneficial for a majority of patients with medically refractory heart failure due to severe left ventricular (LV) systolic dysfunction and prolonged interventricular conduction to improve symptoms and LV performance. An optimally programmed atrioventricular delay (AVD) during CRT can be also important to maximize the response in left ventricular function. Several Doppler echocardiographic methods have been reported to be useful for determination of the optimal AVD. This review will discuss the various Doppler-based approaches to program the AVD in patients that receive CRT.