Misdiagnosis of unroofed coronary sinus syndrome as an ostium primum atrial septal defect by echocardiography: A case report

Abstract

Background: Unroofed coronary sinus syndrome (UCSS) is a rare congenital heart disease, which has variable morphologic features and is strongly associated with persistent left superior vena cava (PLSVC). However, it is often difficult to visualize the left-to-right shunt pathway through the CS by transthoracic echocardiography (TTE).

Case summary: A 37-year-old female was admitted to the hepatological surgery department of a hospital with complaint of subxiphoid pain that had started 1 wk prior. Physical examination revealed a grade 3/6 systolic murmur at the left margin of the sternum, between the 2^nd and 3^rd intercostal cartilage. The patient underwent echocardiography and was diagnosed with ostium primum atrial septal defect (ASD); thus, she was subsequently transferred to the cardiovascular surgery department. A second TTE evaluation before surgery showed type IV UCSS with secundum ASD. Right-heart contrast echocardiography (RHCE) showed that the right atrium and right ventricle were immediately filled with microbubbles, but no microbubble was observed in the CS. Meanwhile, negative filling was observed at the right atrium orifice of the CS and right atrium side of the secundum atrial septal. RHCE identified UCSS combined with secundum ASD but without PLSVC in this patient.

Conclusion: This rare case of UCSS highlights the value of TTE combined with RHCE in confirming UCSS with ASD or PLSVC.

Keywords: Atrial septal defect; Case report; Congenital heart disease; Coronary sinus; Echocardiography; Persistent left superior vena cava; Right heart contrast echocardiography.

Figure 1

Transthoracic echocardiography before surgery. A: Significant enlargement of the right ventricle (anterior-posterior diameter = 43 mm); B: Location of the defect was near the endocardial cushions on apical four-chamber view, which was mistaken for a defect of the ostium primum atrial septal defect (ASD) (arrow); C: When detected on apical four-chamber view by scanning backward, a defect of the coronary sinus (CS) in the terminal portion and normal endocardial cushions were seen (arrow); D: A shunt through the defect of the CS in the terminal portion on apical four-chamber view (arrow); E: Pulse-wave Doppler spectrum showed a shunt during diastole through the defect of the CS in the terminal portion [Vmax = 100 cm/s, pressure gradient (PG) = 4 mmHg]; F: Moderate-to-severe tricuspid regurgitation (Vmax = 337cm/s, PG = 45 mmHg, pulmonary artery systolic pressure = 50 mmHg); G: The defect of the CS in the terminal portion and secundum ASD on subxiphorid biatrial view (arrow, 3.3 cm × 2.0 cm and 1.1 cm); H: Two shunts through the defect of the CS and secundum ASD on subxiphorid biatrial view (arrow); I: Negative filling was observed at the right atrium orifice of the CS and right atrium side of the secundum atrial septal by right-heart contrast echocardiography (arrow). RA: Right atrium; RV: Right ventricle; LA: Left atrium; LV: Left ventricle.

Figure 2

Imaging during the operation. A: Obvious broadening of the coronary sinus (CS) with a partial defect of the CS roof in the terminal portion (3.0 cm × 2.1 cm) was seen upon incision of the right atrium; B: The defect of the CS in the terminal portion was repaired.

Figure 3

Transthoracic echocardiography at 1 wk after surgery. A: The repaired atrial septum was continuous and complete on apical four-chamber view (arrow); B: The repaired coronary sinus (CS) roof was continuous and complete on apical four-chamber view (arrow); C: There was no shunt from the left atrium to right atrium on apical four-chamber view (arrow); D: Trace tricuspid regurgitation (Vmax = 223 cm/s, pressure gradient = 20 mmHg, pulmonary artery systolic pressure = 25 mmHg). RA: Right atrium; RV: Right ventricle; LA: Left atrium; LV: Left ventricle; CS: Coronary sinus.