Evaluation of left atrial degeneration for the prediction of atrial fibrillation: usefulness of integrated backscatter transesophageal echocardiography.
OBJECTIVE
The purpose of this study was to elucidate the usefulness of integrated backscatter (IBS) transesophageal echocardiography (TEE) for the evaluation of atrial degeneration and clarify whether atrial degeneration predicts the occurrence of atrial fibrillation (AF).


BACKGROUND
One of the causes of AF is pathological degeneration of the left atrium (LA). However, there is no appropriate method to evaluate degeneration of the LA in the clinical setting.


METHODS
The IBS images were acquired with TEE with a 4- to 7-MHz transducer. The IBS values were calculated as the average power of the backscattered signal from regions of interest (ROI). In the pathological study, we measured IBS values of 21 left atrial specimens obtained from 10 autopsied hearts. Relative interstitial area in the ROI was automatically calculated by a personal computer. In the clinical study, we measured IBS values of the entire LA wall at 5-mm intervals (except the posterior wall) in 42 patients (18 non-AF patients, 14 paroxysmal AF patients, and 10 chronic AF patients). Each IBS value was color-coded to construct 3-dimensional maps.


RESULTS
There was a weak correlation between the relative interstitial area and IBS values (r = 0.45, p = 0.038). Average corrected IBS values of total voxels in color-coded maps in the AF group (24.4 +/- 6.4 dB) and the paroxysmal AF group (23.9 +/- 9.6 dB) were significantly greater than those in the non-AF group (15.6 +/- 7.4 dB, p = 0.007), whereas there was no significant difference in LA diameter between the paroxysmal AF group (39.4 +/- 6.5 mm) and the non-AF group (36.7 +/- 5.5 mm).


CONCLUSIONS
With IBS-TEE, we can identify an increase in atrial degeneration that might predict the occurrence of AF before LA dilation.
Kubota
Tomoki
T
Regeneration and Advanced Medical Science, Gifu University Graduate School of Medicine, Gifu 501-1194, Japan.
Kawasaki
Masanori
M
Takasugi
Nobuhiro
N
Takeyama
Urara
U
Ishihara
Yoshiyuki
Y
Okubo
Munenori
M
Yamaki
Takahiko
T
Ojio
Shinsuke
S
Aoyama
Takuma
T
Arai
Masazumi
M
Nishigaki
Kazuhiko
K
Takemura
Genzou
G
Fujiwara
Hisayoshi
H
Minatoguchi
Shinya
S
D000368:Aged; D001281:Atrial Fibrillation / Q000000981:diagnostic imaging* / Q000209:etiology; D001344:Autopsy; D016022:Case-Control Studies; D002908:Chronic Disease; D019560:Echocardiography, Three-Dimensional; D017548:Echocardiography, Transesophageal; D005260:Female; D006325:Heart Atria / Q000000981:diagnostic imaging; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012307:Risk Factors; D012680:Sensitivity and Specificity