[Show abstract][Hide abstract] ABSTRACT: Large evidence supports the importance of individualized optimization of cardiac resynchronization therapy in patients with congestive heart failure. The aim of this study was to compare a recently developed intracardiac electrogram (IEGM)-based method with the Doppler echocardiographic (ECHO)-based method to calculate optimal atrioventricular (AV) and interventricular (VV) delays. Ten male patients implanted with a St Jude Medical resynchronization device received AV and VV delay assessment with both the IEGM and the ECHO-based methods. Estimates of the optimal AV and VV delays assessed by the 2 tested methods proved highly comparable. No difference emerged between the IEGM (126.8+/-22.7) and the ECHO (127.3+/-19.8) AV delay values (P=.987). The VV delay suggested by ECHO was highly significantly correlated with the delays calculated by the IEGM method (35+/-27.6 vs 21.31+/-24.31; r(2)=0.78; P<.001). These preliminary data support the evidence that an IEGM based cardiac resynchronization optimization method may be as reliable as a complete ECHO assessment.