Comparison of different approaches for optimization of atrioventricular and interventricular delay in biventricular pacing

Aims: It has been shown that optimizing atrioventricular (AV) andinterventricular (VV) delay improves cardiac performance inpatients with biventricular pacemakers. However, there is nostandard method for optimization available yet. The aim of thisstudy was to compare echocardiographic parameters—displacementimaging, A wave duration, and aortic velocity time integral(VTI)—and acoustic cardiography derived electromechanicalactivation time (EMAT) using different approaches of AV andVV delay optimization. We tested whether the initial optimizationof the AV interval followed by VV optimization at that optimalAV interval or initial optimization of the VV interval followedby AV optimization at the determined optimal VV interval wasaccurate and consistent, and how this compared to testing everyconceivable combination of AV and VV intervals available. Methods and results: A group of 20 patients with biventricular pacemakers was included.Displacement imaging, A wave duration, and aortic VTI were determinedat different combinations of AV (100, 150, 200, 250 ms) andVV (RV40, 0, LV40 ms) intervals. If AV duration was determinedfirst, displacement imaging identified the best setting in 8/20,aortic VTI in 10/20, A duration in 13/20, and EMAT in 18/20patients. With VV duration determined first, the best settingwas more difficult to identify regardless of the method used.There was a poor agreement in optimal AV and VV delays of thedifferent methods, and there was no single patient in whom allfour methods yielded the same delay combination. Conclusion: It is advisable to measure a full grid of AV and VV delays toidentify optimal settings rather than optimizing one of thetwo delays first. Different techniques for delay optimizationresulted in different optimal delay combinations.