Intracardiac delay optimization of biventricular pacing devices currently relies on timeconsuming echocardiographic measurements. Automatic intracardiac electrogram (IEGM) method for atrioventricular (AV) and interventricular (VV) delay optimization was developed by St. Jude, which can be performed during routine device follow-up. Some manufacturers do not provide automated intracardiac electrogram (IEGM) systems for AV and VVdelay optimization in cardiac resynchronization therapy (CRT). We aimed to evaluate the diagnostic accuracy of manual IEGM method in patients undergoing CRT. We included 48 patients previously implanted with Medtronic Syncra, cardiac resynchronization therapy devices. One month after CRT implantation all patients underwent standard device interrogation followed by optimization of the CRT pacemaker settings by IEGM method and by echocardiography. Patients had a mean age of 60,7 ± 11,8 years and 33 (68,8%) were males. After the CRT implantation, ejection fraction of the left ventricle increased from 28,0 ± 7,9 % to 39,1 ± 11,0 % (P<0.001). Optimal aortic velocity time integral (AVTI) was obtained when VV was set to 20 – 50 ms left ventricular pre-activation. There was a strong correlation between VV values determined by echocardiography and IEGM (ρ = 0.823, P<0.001). We found no significant difference in sensed atrioventricular interval, paced atrioventricular interval, LVOT VTI and VV values between echocardiography and IEGM method. However, IEGM was significantly less time consuming than echocardiography [20 (10 – 28) vs. 40 (35 – 60) minutes, P<0.001]. The automated programmer-based IEGM method provides a reliable and simpler alternative to standard techniques for CRT optimization. Our study indicates that manual IEGM method may be good alternative to echocardiography and automated IEGM method. It also emphasizes the need for implementation of automated IEGM systems by all CRT device manufacturers.