CONTENT

Isolated coronary sinus atresia (CSOA) is an extremely rare congenital malformation with an incidence <0.1%, characterized by complete occlusion of the coronary sinus ostium in the absence of other major cardiac defects. Most cases drain via a persistent left superior vena cava, while direct cardiac venous-left atrial communication is uncommon and may cause right-to-left shunt, chronic headache, or paradoxical embolism.

We report a 57-year-old female with a 20-year history of exertional and stress-induced headaches. Initial transcranial Doppler bubble test and Transthoracic contrast echocardiography demonstrated grade 3 atrial-level right-to-left shunt, leading to a misdiagnosis of patent foramen ovale (PFO) (Figure 1A and B). Transesophageal echocardiography subsequently confirmed an intact atrial septum (Figure 1C). Cardiac computed tomography angiography identified isolated CSOA with the great cardiac vein bifurcating into 4.3 mm left atrial and 1.9 mm right atrial branches, with no associated anomalies (Figure 1D and E). Cardiac computed tomography angiography (CTA) with three-dimensional reconstruction confirmed isolated CSOA (Figure 1F).

The patient underwent successful surgical correction, with complete resolution of headaches and no residual shunt at 6-month follow-up. This rare dual drainage variant should be considered in the differential diagnosis of right-to-left shunt when PFO is excluded, and cardiac CTA is essential for definitive anatomical characterization.

Footnotes

Artificial Intelligence Usage Statement: The authors declare that no artificial intelligence (AI)-assisted technologies (including large language models, chatbots, or image generators) were used in the production of this manuscript. All content was written, edited, and reviewed exclusively by the authors, who take full responsibility for the accuracy, integrity, and originality of the work.

Informed Consent: Written informed consent was obtained from the patient.

Declaration of Interests: The authors have no conflicts of interest to declare.