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

Abstract

BackgroundReproducibility and hemodynamic efficacy of optimization of AV delay (AVD) of cardiac resynchronization therapy (CRT) using invasive LV dp/dtmax are unknown.Method and results25 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 < 0.01 by F test).Compared with AAI pacing, the hemodynamic increment from CRT, with the nominal AV delay was LVSBP 2% and LVdp/dtmax 5%, while CRT with pre-determined optimal AVD gave 6% and 9% respectively.ConclusionsBecause of inevitable background fluctuations, optimization by absolute dp/dtmax has poor same-day reproducibility, unsuitable for clinical or research purposes. Reproducibility is improved by comparing to a reference AVD and making multiple consecutive measurements. More than 6 measurements would be required for even more precise optimization — and might be advisable for future study designs. With optimal AVD, instead of nominal, the hemodynamic increment of CRT is approximately doubled.

Atrioventricular dyssynchrony from empiric device settings is common in cardiac resynchronization therapy and adversely impacts left ventricular morphology and function

“…The consequences of an inappropriately prolonged AV delay may include suboptimal LV preload, diastolic mitral regurgitation, and permissive native LV conduction, which would render CRT ineffective . In our study, the algorithmic AV delays of 165±56 ms (Group 1) and 152±25 ms (Group 2) are longer than recommended but consistent with reports from previous clinical trials . Despite theoretically longer AV delays, there were nine patients with A‐wave truncation on their post implantation echocardiogram, suggestive of an AV delay that was set too short for these patients.…”

2016 ESC Guidelines for the diagnosis and treatment of acute and chronic heart failure

“…Rola prób optymalizacji opóźnień AV oraz VV po implantacji urządzenia, przy użyciu metod elektrokardiograficznych, echokardiograficznych lub hemodynamicznych nie jest jasna, można je jednak rozważyć u osób, u których nie doszło do zadowalającej odpowiedzi na CRT [296,297].…”

British randomised controlled trial of AV and VV optimization (“BRAVO”) study: rationale, design, and endpoints

“…Without these steps noise is likely to overwhelm the signal and the results obtained are unlikely to be reliable [44,45]. …”