A real-time three-dimensional echocardiographic validation of an intracardiac electrogram-based method for optimizing cardiac resynchronization therapy.

INTRODUCTION: Although optimization of atrioventricular and interventricular delays has been demonstrated to improve hemodynamics in patients with cardiac resynchronization therapy (CRT), the required time-consuming procedure discourages its use in clinical practice. Recently, a new method for CRT optimization based on the intracardiac electrogram (IEGM) detected by the implanted leads, has been developed. We evaluated the effectiveness of this method in improving left ventricular (LV) asynchrony and performance using real-time 3D echocardiography (RT3DE). METHODS AND RESULTS: Twenty patients with CRT were prospectively studied. RT3DE was performed before and after IEGM optimization. The standard deviation of the time to the regional LV minimum systolic volume (Tmsv) for all 16 segments (Tmsv 16-SD), six basal and six mid segments (Tmsv 12-SD), and the six basal segments (Tmsv 6-SD) were assessed as a asynchrony indexes. LV end-diastolic and end-systolic volumes (EDV, ESV), stroke volume (SV), ejection fraction (EF), myocardial performance index (MPI), ejection time (ET), and filling time (FT), corrected by R-R interval, were also evaluated. After IEGM optimization, as compared with baseline Tmsv 12-SD and Tmsv 16-SD decreased (P = 0.01, P< 0.001, respectively), EF and SV improved (P < 0.001, P = 0.01 respectively), FT/RR and ET/RR increased (P = 0.02 for both), and MPI improved (P < 0.001). Tmsv 6-SD, EDV and ESV did not change. CONCLUSION: A simple IEGM-based method of CRT optimization decreased LV dyssynchrony and improved systolic function.