Giant Coronary Sinus

Abstract

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A 25-year-old woman with 10 years of worsening dyspnea had a mid-diastolic murmur in the left inframammary region. Two-dimensional echocardiography showed thickening of the mitral valve leaflets with a doming anterior mitral leaflet and restricted posterior mitral leaflet movement, which suggested rheumatic involvement of the mitral valve. An echo-free structure in the posterior atrioventricular groove suggested an enlarged coronary sinus, which was confirmed in parasternal long-axis view (Fig. 1) and modified apical 4-chamber view with posterior tilt (Fig. 2). The mitral valve area was 0.6 cm² by planimetry. The tricuspid valve was thickened and doming, and color-flow Doppler echocardiography showed moderate tricuspid regurgitation with a gradient of 26 mmHg (Fig. 3). There was no significant tricuspid stenosis. A contrast echocardiogram showed that air bubbles entered the right atrium through the coronary sinus when contrast medium was injected through the left antecubital vein, which suggested persistent left superior vena cava (Fig. 4). The maximum coronary sinus diameter was 4.5 cm. Such extreme dilation is quite uncommon.

Fig. 1 Two-dimensional echocardiography (parasternal long-axis view) shows a thickened mitral valve (MV) and an extremely dilated coronary sinus (CS).

Ao = aorta; DA = descending aorta; LA = left atrium; LV = left ventricle; RV = right ventricle

Fig. 2 Two-dimensional echocardiography (modified apical 4-chamber view) shows a dilated coronary sinus (CS).

RA = right atrium; RV = right ventricle

Fig. 3 Color-flow Doppler echocardiography (modified apical 4-chamber view) shows tricuspid regurgitation (TR).

Fig. 4 Contrast echocardiography (modified apical 4-chamber view) shows air bubbles entering the right atrium (arrow) from the coronary sinus (CS).

Real-time motion image is available at www.texasheart.org/journal.

Comment

The coronary sinus is rarely seen on echocardiography in healthy persons.¹ The differential diagnosis of dilated coronary sinus includes right ventricular dysfunction, right atrial hypertension, and anomalous venous drainage into the coronary sinus.² These abnormalities include persistent left superior vena cava, total anomalous pulmonary venous return, coronary atrioventricular fistula, and anomalous hepatic venous drainage. Rarer causes of dilated coronary sinus include postoperative obstruction, thrombosis or ventricularization, and unroofing of the sinus. Extreme dilation of the coronary sinus can cause substantial problems during septal puncture in balloon mitral valvotomy. Recognizing dilation in advance is also important if a left superior venous approach to the heart is considered—for example, if venous catheterization or pacemaker or cardioverter-defibrillator implantation is required—and if retrograde cardioplegia for coronary artery bypass grafting is planned.^3,4

Our patient's coronary sinus dilation was due to multiple factors: persistent left superior vena cava, organic tricuspid valve disease, and severe mitral stenosis. Proper diagnosis aids the development of appropriate approaches before percutaneous intervention or surgery.