Non-invasive Determination of the Optimized Atrioventricular Delay in Patients with Implanted Biventricular Pacing Devices

BACKGROUND: Biventricular (BiV) is extensively used in the treatment of congestive heart failure but so far no recommendations for optimized programming of atrioventricular-delay (AVD) settings have been proposed. Can AVD optimization be performed using a simple formula based on non-invasive doppler-echocardiography? METHODS: 25 patients (ejection fraction 30±8%) received BiV ICDs. Doppler-echocardiographic evaluation of diastolic and systolic flow was performed for different AVDs (30ms to 150ms) and different stimulation sites (left ventricular (LV), right ventricular and BiV). The optimal atrioventricular delay was calculated applying a simple formula based on systolic and diastolic mechanical delays determined during doppler-echocardiography. RESULTS: The mean optimal AVD was calculated to be 112±29ms (50 to 180ms) for BiV, 95±30ms (65 to 150ms) for LV and 75±28ms (40 to 125ms) for right ventricular pacing with wide interindividual variations. Compared to suboptimal AVDs diastolic optimization improved preejection and ejection intervals independent to pacing site. Optimization of the AVD significantly increased ejection time during BiV pacing (279ms versus 266ms; p<0.05). Compared to LV or right ventricular pacing BiV pacing produced the shortest mean pre-ejection and longest ejection intervals as parameters of improved systolic ventricular contractile synchrony. Diastolic filling times were longest during BiV pacing compared to LV or RV pacing. CONCLUSIONS: Individual programming of BiV pacing devices increases hemodynamic benefit when implementing the inter-individually widely varying electromechanical delays. Optimization applying a simple formula not only improves diastolic ventricular filling but also increases systolic functional parameters.