Optimization of the atrioventricular (AV) and interventricular (VV) timings of the CRT is the most supposed correctable variable to improve the rate of CRT responder. The aim of the present study has been to evaluate if there is a specific subgroup of patients who can actually benefit the most from a hemodynamic optimization of AV. This is a prospective, observational single-center study that enrolled consecutive patients with clinical indication for CRT; all patients were implanted with CRT-D devices with SonR technology, able to automatically adjust AV and VV delay on a weekly basis. Among 57 patients, 39 (69%) showed a LVESV reduction > 15%. The SonR was able to modify the pacing parameters, but an increase of left atrial diameter was associated to a reduced AV variability, suggesting that an impaired left atrial function could potentially reduce the ability of the SonR algorithm to adjust the correct timing of pacing. Graphical abstract Patients with respectively a high (A) and low (B) AV timing variability, among several parameters that could potentially influence the AV timing, only left atrial dimensions demonstrated a significant impact. In fact an increase of left atrial diameter was associated to a reduced AV variability, suggesting that an impaired left atrial function could potentially reduce the ability of the SonR algorithm to adjust the correct timing of pacing.
Keywords: AV optimization; CRT; Hemodynamic sensor; Left atrial dimension.