A Study on the Correlation the Cardiac Cycle and the Size of the Left Atrial Appendage in Cardiac CT

This study aimed to analyze the size changes of the left atrial appendage in atrial fibrillation patients to minimize complications of left atrial appendage occlusion and to determine the optimal cardiac cycle for selecting the appropriate device size. The study included 31 persistent atrial fibrillation patients and 69 paroxysmal atrial fibrillation patients in sinus rhythm, measuring the maximum, mean and perimeter-derived diameters of the left atrial appendage's orifice and landing zone at 10% intervals throughout the entire cardiac cycle. Analyzes included the distribution of size values for each cycle, one-way ANOVA, relative differences, frequency of maximum values, and interobserver reliability. As a result, the maximum, mean and perimeter-derived diameter of the left atrial appendage orifice and landing zone all showed maximum size value in the systolic phase, especially in the 40%. As it progressed towards end-diastole, the diameter progressively decreased. The relative differences in the atrial fibrillation group were more than 50% at both the orifice and landing zone, and in the sinus rhythm group, these differences exceeded 70% at the same points. The One-way ANOVA revealed significant differences in the left atrial appendage size in each cardiac cycle(p<0.05) Frequency analysis showed that the 40% had the highest occurrence of maximum values for both areas. The assessment of interobserver reliability showed excellent consistency. All groups, the cardiac cycle phase showing the maximum left atrial appendage size was the systolic phase, especially at the 40% phase. Therefore, measuring the size of the left atrial appendage at 40% of the cardiac cycle before left atrial appendage occlusion may help minimize measurement errors and aid in selecting an appropriate device size.