Severity of pseudofilling defect in the left atrial appendage on cardiac computed tomography is a simple predictor of the degree of left atrial emptying dysfunction in patients with chronic atrial fibrillation.
OBJECTIVE
The purpose of our study was to investigate the clinical relevance of a pseudofilling defect in the left atrial appendage (LAA) detected on coronary computed tomography (CT) angiography (CCTA) as an indicator of impaired left atrial (LA) volumetric function in patients with chronic atrial fibrillation (CAF).


METHODS
Forty-two patients with CAF underwent CCTA. Quantitative and visual measurements of contrast enhancement of the LAA were performed, and they were correlated with results of CT volumetric functional analysis of the LA. Four volumetric parameters representing LA function were measured: maximum (LAVmax) and minimum volumes of the LA (LAVmin) through the entire cardiac cycle; LA emptying volume (LAEV); and LA emptying fraction (LAEF). All volumetric parameters were standardized by body surface area to adjust for variation in LA size among patients. For quantitative measurement, the CT attenuation was measured at the LAA and the LA to calculate an LAA/LA attenuation ratio. For visual measurement, contrast enhancement of the LAA was categorized into 3 groups; no filling defect, mild-to-moderate pseudofilling defect, and severe pseudofilling defect group. The Spearman correlation coefficient and the Kruskal-Wallis test were used for statistical analysis.


RESULTS
The LAA/LA ratio showed a strong positive correlation with LAEV (r = 0.52; P < 0.001) and LAEF (r = 0.69; P < 0.001). The LAEV in the no pseudofilling defect group and the mild-to-moderate and severe pseudofilling defect groups were 16.1 ± 8.4, 10.8 ± 3.1, and 6.7 ± 4.9 mL/m², respectively (P < 0.001). The LAEF in each group were 24.2 ± 13.8%, 12.0 ± 3.4%, and 6.9 ± 3.1%, respectively (P < 0.001).


CONCLUSIONS
The severity of pseudofilling defect in the LAA on CCTA could predict the degree of LA emptying dysfunction in patients with CAF.
Department of Radiology, St. Luke's International Hospital, Tokyo, Japan. mitishi@luke.or.jp
Mitsutomi
M
Ishiyama
Gensuke
G
Akaike
Masaki
M
Matsusako
Takuya
T
Ueda
Akari
A
Makidono
Sachiko
S
Ohde
Atsushi
A
Mizuno
Shuzo
S
Nishihara
Yukihisa
Y
Saida
D000368:Aged; D000369:Aged, 80 and over; D020517:Atrial Appendage / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D001281:Atrial Fibrillation / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D002908:Chronic Disease; D003287:Contrast Media; D017023:Coronary Angiography / Q000379:methods*; D004562:Electrocardiography; D005260:Female; D006801:Humans; D007479:Iopamidol; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011857:Radiographic Image Interpretation, Computer-Assisted; D012720:Severity of Illness Index; D014057:Tomography, X-Ray Computed / Q000379:methods*
D003287:Contrast Media; D007479:Iopamidol