The atrial diverticulum was considered as one of the rare cardiac anomalies in the past. Recently, pathologies such as diverticula and accessory appendages are detected at higher rates due to the increasing use of MDCT in cardiac imaging.
Atrial diverticula are usually asymptomatic structures. It is diagnosed incidentally during cardiac CT. The etiology of the left atrial diverticulum is unclear. Most patients do not have hemodynamic disturbances that create the appropriate environment for the development of acquired diverticulum. It is, therefore, more likely to have a congenital history. This study aimed to evaluate the prevalence, location, and size of left atrial accessory appendages and diverticulum in the Turkish population.
In the literature, Wan et al. , Genç et al. , Abbara et al. , Holda et al. , Incedayı et al. , Lazoura et al.  conducted similar studies by retrospectively examining cardiac CTs. A summary of these studies with different patient numbers is given in Tables 3 and 4.
Our study stands out as we included a larger sample size than what is in the literature. In our study, 238 atrial diverticula were found in 234 (16.5%) of the patients, accessory appendage in 93 (6.5%), and atrial diverticula and accessory appendage association in eight (0.5%) patients. The frequency of atrial diverticula in the literature varies between 15 and 48.4% , and the value we found in our study is consistent with the general literature. The values found in the studies by Genç et al.  and Incedayı et al.  were higher than the literature in general and our study. The localization distribution of the left accessory appendage is consistent with the study of Lazoura et al. . We think that the reason why it is inconsistent with other studies is due to differences in anatomical localization classification. Accessory appendage can be observed in a wide range of 6.5–28% in the literature . Our study is compatible with the literature.
In our study, we could not find a statistically significant difference between men and women in patients with atrial diverticula. When previous studies were examined, Wan et al.  and Seker et al.  reported similar results. But, Abbara et al.  and Genç et al.  found it significantly higher in males.
Our study showed that the left atrial diverticulum was most commonly located in the anterosuperior wall of the atrium and was consistent with the literature [1, 5, 6, 8]. Also we found that the least common left atrial diverticula was the posterosuperior wall and was consistent with previous studies . Wan et al.  reported that posterior left atrial diverticulum is more common in women. In our study, we could not detect a relationship between gender, diverticula localization, and size.
In addition to diverticula ratios, the structure of the diverticula has been investigated in the literature. In the study by Genç et al. , 440 (62%) of the atrial diverticulum were found to be cystic, 219 (31%) tubular, and 49 (7%) atypical shaped. In the study of Wan et al. , 20 (74.1%) of the 27 diverticulums detected were cystic and 7 (25.9%) tubular-shaped. In our study, 126 (52%) of 238 diverticula were cystic and 112 (47%) were tubular. The predominance of a diverticulum in cystic character is consistent with the literature.
They are usually asymptomatic. Recently, they have been suspected to cause atrial fibrillation by triggering conduction abnormalities, and various studies have been conducted to investigate the relationship between them. Many studies did not find a significant relationship [1, 5, 6, 11]. However, the evaluation of variations can guide the clinician in preventing possible complications, especially in patients with atrial fibrillation, before radiofrequency ablation therapy or in catheterizations.
MDCT provides a more detailed evaluation of cardiac anatomical structures. Allows the detection of a small diverticulum. Despite the growing role of MDCT in clinical practice, there is no consensus on the preprocedural use of MDCT. Since the clinical role of the diverticulum and appendage has not been fully established, routine cardiac CT may not be cost-effective. However, it is a valuable method in clinical requirements and in preventing possible complications before the procedure.
The most important limitations of this study are the retrospective analysis and the lack of clinical findings. No pathological correlation could be made between the findings and the patient. In addition, although the morphological findings of the atrial diverticulum and appendage are compatible with the literature, the lack of reliability analysis between different evaluators may carry a risk of bias.
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