Effect of atrioventricular optimization on circulating N-terminal pro brain natriuretic peptide following cardiac...

Following CRT, atrioventricular (AV) optimization is not routinely practised. To evaluate its clinical utility, we examined the effect of AV delay optimization on the prognostic biomarker NT-proBNP.

We prospectively studied 72 patients (mean age 73 ± 12.5 years, 70.8% male, 55.6% ischaemic) undergoing iterative AV optimization. Patients were divided into those whose nominal setting appeared ideal and not changed (Group 1, n = 22) and those whose AV delay was optimized (Group 2, n = 50). All patients underwent NT-proBNP assessment prior to CRT, and pre- and a median 5 days post-optimization. Compared with Group 1, NT-proBNP fell significantly in Group 2 patients (median 474 pg/mL) following optimization (P = 0.00001). A significant change in filling pattern (defined as a change in AV delay >50 ms) was required in 30% of patients, and it was this subgroup that derived the greater reduction in NT-proBNP levels [-1407 pg/mL, interquartile range (IQR) -3042 to -346 pg/mL] compared with those requiring <50 ms AV delay change (-125 pg/mL, IQR -1038 to 6 pg/mL), P = 0.0011. The benefit of AV optimization was principally observed in reverse remodelling non-responders (median -2167 pg/mL, IQR -3042 to -305 pg/mL) and in patients with a pseudonormal or restrictive filling pattern (median -1407 pg/mL, IQR -2809 to -342 pg/mL), compared with those with more benign diastolic filling (median - 264 pg/mL, IQR -1038 to -21 pg/mL), P = 0.033.

In one-third of patients, major filling pattern changes are achieved with AV optimization, associated with subsequent rapid falls in NT-proBNP. The greater the AV delay change, the larger the NT-proBNP fall, and non-responders and those with restrictive or pseudonormal filling despite CRT are most likely to benefit.