PURPOSE It has been well-known that higher temporal resolution is good to the coronary CT angiography in patients with higher heart rate(>65 bpm).Using the third dual-source(DS)CT and 66-ms temporal resolution,we aimed to explore the optimal end-systolic reconstruction phase with different high heart rates in different coronary segments.METHOD AND MATERIALS 15 patients with high heart rate(>65 bpm)underwent coronary CT angiography with the third-generation dualsource CT.End systolic reconstructions were performed at every 10 ms from 200 ms to 450 ms after R wave.Based on the American Heart Association coronary segmentation guidelines,the imaging quality of each segment was analyzed by two radiologists with 5-point Likert scales(1-2,poor; 3,fair; 4,good; 5,excellent).The initial phase,the end phase with fair image quality,and the temporal window between the two phases were recorded.Pearson correlation was used to analysis the relationship between the heart rates and the end-systolic phases of each segment.RESULTS The heart rates were from 66 to 107 bpm(77±9.84 bpm).There was the correlation between HR and the initial phase only in S11(r=0.837).There was the correlation between HR and the end phase in S1(r=-0.641),S2(r=-0.784),S3(r=-0.699),S5(r=-0.625),S6(r=-0.635)and S11(r=- 0.541),and between HR and the temporal window in S1(r=-0.695),S2(r=-0.541),S5(r=-0.633),S6(r=-0.635)and S11(r=-0.756).CONCLUSION In the end-systolic reconstruction phases,the end phase with fair image quality will move forward and the temporal window will be shortened in S1,S2,S5,S6 and S11 with the elevation of heart rate.