Abstract: AIM To use ultrasound speckle tracking imaging (STI) in studying the correlation between left atrial strain value and new onset atrial fibrillation (AF) after coronary artery bypass grafting (CABG). METHODS Changes of left atrial systolic functions were measured by STI technique in 42 coronary heart disease (CHD) patients and 30 normal subjects were used as the control group. RESULTS Compared with those in the control group, LAD was larger, E was higher, A was lower, E/A was higher, and Ss, Sa and SRs were lower in postoperative AF group, with statistically significant difference (P<0.05). Compared with those in the control group, no significant difference was found in the above indexes in the postoperative non-AF group. There was statistically significant difference in the above indexes between the postoperative AF group and postoperative non-AF group (P<0.05). CONCLUSION Preoperative STI technique used to analyze the value of left atrial strain predicts effectively the occurrence of atrial fibrillation after CABG.