Abstract: Objective: To evaluate the dynamic changes of the right atrial structure and function in atrial fibrillation using the acoustic quantification (AQ) technique. Methods: Dog models with chronic atrial fibrillation were established by rapid atrial pacing. Right atrial AQ waveforms were recorded before rapid atrial pacing and after pacing for 1, 4 and 8 weeks. Results: Compared with the control group, ESV, EDV and EREV of the atrial fibrillation group were increased, and EF and CV were decreased (P＜0.05) at 4 weeks after pacing. And 8 weeks after pacing, ESV, EDV and EREV were significantly increased (P＜0.001), while EF and PAER significantly decreased (P＜0.001) and CV was also significantly decreased (P＜0.05), and the other parameters had no significant changes in the pacing progress. In the atrial fibrillation group, compared with those before pacing, right atrial AQ parameters had no significant changes at 1 week after pacing (P＞0.05); ESV, EREV and EDV were significantly increased (P＜0.05) and EF was significantly decreased (P＜0.05) at 4 weeks after pacing, while ESV, EREV and EDV were significantly increased (P＜0.001) and EF and PAER were significantly decreased (P＜0.001) at 8 weeks after pacing. Compared with the 1week group, ESV, EREV and EDV were significantly increased (P＜0.01) and EF and PAER were significantly decreased (P＜0.01) at 8 weeks after pacing, and other parameters had no statistical significance. Conclusions: Atrial fibrillation may result in right atrial booster pump and conduit function impairment but no changes of reservoir function. AQ technique may be used as a valuable noninvasive method for evaluating right atrial structure and function in atrial fibrillation.

Key words: Acoustic quantification, Atrial fibrillation, Atrial function, right