V-V delay interval optimization in CRT using echocardiography compared to QRS width in surface ECG

Introduction: CRT had become a standard of treatment for patients with drug refractory heart failure. The presence of many cases of non-responders raises the need for device optimization echocardiography that is an established tool used to optimize CRT programming, but it is time-consuming. It was not yet defined whether a QRS width-based strategy may be a helpful tool for device programming. Aim of study: The aim of this study is to compare the optimal interventricular delay interval (V-V interval) obtained by echo with that obtained by a simpler method using QRS width in surface ECG. Methods and results: Twenty patients with implanted CRT were enrolled. All patients underwent echocardiographic optimization of the (A-V interval) after which five different V-V intervals (LV. +. 30, LV. +. 60, RV. +. 30, RV. +. 60, L. +. R0) were compared measuring Left Ventricular Outflow Tract Velocity Time Integral (LVOT VTI) as a surrogate for ejection fraction. A 12-lead ECG was recorded and QRS duration was measured in the lead with the greatest QRS width. The ECG optimized V-V interval was defined according to the narrowest achievable QRS interval among the 5 V-V intervals. The echocardiographic-optimized V-V interval was defined according to the highest LVOT VTI among the 5 V-V intervals. The echocardiographic-optimized V-V interval was left ventricle. +. 30. ms in 2 patients (10%), left ventricle. +. 60. ms in 8 pts (40%), simultaneous pacing in 8 pts (40%) and right ventricle. +. 30. ms in 2 pts (10%).ECG method (using QRS width), had 85% coincidence with the echocardiographic method (using LVOT VTI) (κ=0.906), (r=0.81 P<0.001). Conclusion: Significant correlation appeared to exist during optimization of CRT between VV programming based on the shortest QRS interval at 12-lead ECG pacing and that based on highest LVOT VTI by echocardiography. A combined ECG and echocardiographic approach could be a more convenient solution in performing V-V optimization. © 2012.