Objective To assess the value of the retrospective electrocardiographic gating technique with electrocardiographic editing in 64 multislice spiral CT coronary angiography(MSCTCA).Methods Sixty-seven patients with suspicion of coronary artery disease underwent coronary angiography with 64 MSCT,including arrhythmia(n=37,17 with atrial extrasystoles and 20 with ventricular extrasystoles),unequal R-R intervals resulted from the absence of trigger points on partial R waves(n=14)and inaccurate trigger points(n=16).The images were reconstructed with the retrospective electrocardiographic gating technique after electrocardiacgraphic signal editing and processed On the postprocessing workstation.Results The electrocardiographic signal editing was failed in one patient with atrial extrasystole.According to the image quality,763 segments of coronary arteries in 66 patients were defined as excellent(n=473,62.0%),good (n=213,27.9%),moderate(n=51,6.7%)or poor(n=26,3.4%)and divided into 4 groups.The images of 737 segments(96.6%)of coronary arteries were diagnostable.The Results of CT angiography in 12 patients were compared with coronary angiography(CAG),and the sensitivity of 64-slice spiral CT for the≥50% stenosis and<50% stenosis were 84.6%(22/26)and 83.3%(10/12),respectively.The specificity was 96.3%(105/109)and the negative predictive value was 97.2%(105/108)in the diagnosis of coronary artery stenosis.Conclusion The retrospective electrocardiographic gating technique combined with electrocardiographic signal editing expands the applications of 64 MSCTCA. Key words: Coronary angiography; Tomography; X-ray computed