Comparison of different invasive hemodynamic methods for AV delay optimization in patients with cardiac resynchronization therapy: Implications for clinical trial design and clinical practice

Background Reproducibility and hemodynamic efficacy of optimization of AV delay (AVD) of cardiac resynchronization therapy (CRT) using invasive LV dp/dtmax are unknown. Method and results 25 patients underwent AV delay (AVD) optimisation twice, using continuous left ventricular (LV) dp/dtmax, systolic blood pressure (SBP) and pulse pressure (PP). We compared 4 protocols for comparing dp/dtmax between AV delays:Immediate absolute: mean of 10 s recording of dp/dtmax acquired immediately after programming the tested AVD,Delayed absolute: mean of 10 s recording acquired 30 s after programming AVD,Single relative: relative difference between reference AVD and the tested AVD,Multiple relative: averaged difference, from multiple alternations between reference and tested AVD. We assessed for dp/dtmax, LVSBP and LVPP, test–retest reproducibility of the optimum. Optimization using immediate absolute dp/dtmax had poor reproducibility (SDD of replicate optima = 41 ms; R2 = 0.45) as did delayed absolute (SDD 39 ms; R2 = 0.50). Multiple relative had better reproducibility: SDD 23 ms, R2 = 0.76, and (p