Randomized prospective trial of atrioventricular delay programming for cardiac resynchronization therapy

Objectives. The purpose of this study was to determine if AV delay optimization with continuous-wave Doppler aortic velocity-time integral (VTI) is clinically superior to an empiric program in patients treated with cardiac resynchronization therapy (CRT) for severe heart failure. Background. The impact of AV delay programming on clinical outcomes associated with CRT is unknown. Methods. A randomized, prospective, sing le-blind clinical trial was performed to compare two methods of AV delay programming in 40 patients with severe heart failure referred for CRT. Patients were randomized to either an optimized AV delay determined by Doppler echocardiography (group 1, n = 20) or an empiric AV delay of 120 ms (group 2, n = 20) with both groups programmed in the atriosynchronous biventricular pacing (VDD) mode. Optimal AV delay was defined as the AV delay that yielded the largest aortic VTI at one of eight tested AV intervals (between 60 and 200 ms). New York Heart Association (NYHA) functional classification and quality-of-life (QOL) score were compared 3 months after randomization. Results. Immediately after CRT initiation with AV delay p rogramming, VTI improved by 4.0 ± 1.7 cm vs 1.8 ± 3.6 cm (P < .02), and ejection fraction (EF) increased by 7.8 ± 6.2% vs 3.4 ± 4.4% (P < .02) in group 1 vs group 2, respectively. After 3 months, NYHA classification improved by 1.0 ± 0.5 vs 0.4 ± 0.6 class points (P < .01), and QOL score improved by 23 ± 13 versus 13 ± 11 points (P < .03) for group 1 vs group 2, respectively. Conclusions. Echocardiography-guided AV delay optimization using the aortic Doppler VTI improves clinical outcomes at 3 months compared to an empiric AV delay program of 120 ms.