Evaluation of Left Atrial Degeneration for the Prediction of Atrial FibrillationUsefulness of Integrated Backscatter Transesophageal Echocardiography
Tomoki Kubota, MD,
Masanori Kawasaki, MD, PhD*,
Nobuhiro Takasugi, MD,
Urara Takeyama, MD, PhD,
Yoshiyuki Ishihara, MD,
Munenori Okubo, MD, PhD,
Takahiko Yamaki, MD,
Shinsuke Ojio, MD, PhD,
Takuma Aoyama, MD, PhD,
Masazumi Arai, MD, PhD,
Kazuhiko Nishigaki, MD, PhD,
Genzou Takemura, MD, PhD,
Hisayoshi Fujiwara, MD, PhD,
Shinya Minatoguchi, MD, PhD
Regeneration and Advanced Medical Science, Gifu University Graduate School of Medicine, Gifu, Japan
* Reprint requests and correspondence: Dr. Masanori Kawasaki, Regeneration and Advanced Medical Science, Gifu University Graduate School of Medicine, 1-1 Yanagido, Gifu 501-1194, Japan (Email: masanori{at}ya2.so-net.ne.jp).
Objectives: 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.
Key Words: atrial fibrillation • integrated backscatter • tissue characterization • transesophageal echocardiography
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Abbreviations and Acronyms
| | AF = atrial fibrillation | | ANP = atrial natriuretic peptide | | BNP = brain natriuretic peptide | | cIBS = corrected integrated backscatter | | IBS = integrated backscatter | | LA = left atrium | | LAA = left atrial appendage | | PAF = paroxysmal atrial fibrillation | | ROI = region-of-interest | | TEE = transesophageal echocardiography |
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