A preliminary investigation of the left atrial suspended cord and its significance as revealed by coronary CT angiography: an observational study with a systematic literature review.

BACKGROUND

The occurrence of suspended cords of the left atrium (SCLA) is rare and has seldom been described. The purpose of this study was to summarize the cases of SCLA accidentally detected by coronary CT angiography (CCTA), describe their imaging features, conduct a preliminary analysis of their clinical significance, and review relevant literature.

METHODS

A total of 10,796 patients who underwent CCTA examinations from July 2020 to November 2021 were consecutively selected. The original and three-dimensional reconstruction images were reviewed to identify patients with SCLA. A control group was selected in a 1:2 ratio based on age, BMI, sex, and education level. The imaging characteristics and clinical data of the two groups were collected and compared. The case group was divided into two subgroups based on the starting and ending positions of the SCLA: Group 1 with the SCLA between the free wall and free wall, and Group 2 with the SCLA between the septum wall and free wall. The clinical features of these subgroups were compared. Furthermore, a review of literature on SCLA published in the past fifteen years that includes its clinical and imaging features was conducted.

RESULTS

In this study, a total of 35 patients were found to have SCLA, resulting in an incidence rate of approximately 0.32%. After excluding 1 patient for whom clinical features could not be obtained, the case group included a total of 18 males and 16 females, with a male-to-female ratio of 1:1 and a median age of 57.00 (52.00-64.00) years. It was found that 19 (55.88%) cases of SCLA were located near the right superior pulmonary vein ostia, while no SCLA was found near the left lower pulmonary vein orifice. A significant difference in the incidence of atrial arrhythmia between the two groups was observed (p = 0.009). Additionally, 3 patients (8.82%) in the SCLA group had a history of transient cerebral ischemic attack (TIA), which was significantly different from that in the control group (p = 0.035). The anteroposterior and transverse diameters of the left atrium were longer in the case group than in the control group (p < 0.05), but there was no significant change in left atrial volume. Subgroup analyses found no significant difference in the incidence of cerebral infarction, atrial arrhythmia, or other intracardiac structural malformations, although there was a significant difference in cord length (p = 0.013), with the length of SCLA in Group 1 and Group 2 being 2.64 ± 0.99 cm and 3.39 ± 0.68 cm, respectively. Notably, only 1 of these 34 patients was diagnosed based on echocardiography, whereas all cases were perfectly visualized using CCTA.

CONCLUSION

SCLA is rare. CCTA can accurately detect and depict this abnormal structure as compared to echocardiography. SCLA may be linked to a higher incidence of atrial arrhythmias or transient ischemic attacks. It is important for radiologists and cardiovascular experts to recognize this structure, and further investigation is necessary to determine its clinical significance.