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Updated: Aug 10, 2026
Murine Fetal Echocardiography
Published on: February 15, 2013
The coronary sinus in the fetus
1Division of Pediatric Cardiology, Hadassah-University Hospital, Jerusalem, Israel.
Insights
Fetal echocardiography can readily detect the coronary sinus, establishing normal dimensions throughout gestation. An enlarged coronary sinus in fetuses often indicates a persistent left superior vena cava.
Area of Science:
- Fetal cardiology
- Medical imaging
- Congenital abnormalities
Background:
- The coronary sinus (CS) normally drains cardiac venous blood to the right atrium.
- CS dilation can occur due to volume or pressure overload.
Purpose of the Study:
- Assess the feasibility of fetal CS detection.
- Establish normal CS dimensions across gestation.
Main Methods:
- Fetal echocardiography in 78 normal fetuses (16-40 weeks).
- CS measured in 4-chamber or parasternal short axis views.
- Comparison with 9 fetuses with dilated CS.
Main Results:
- Successful CS imaging in 97.4% of fetuses.
- Normal CS diameter ranged from 1-3.2 mm, correlating with gestational age (r=0.86).
- Dilated CS fetuses (n=9) had persistent left superior vena cava (PLSVC), with CS diameter ~3x larger (P<0.0001).
Conclusions:
- Fetal CS is easily identified via echocardiography.
- Normal CS dimensions increase with gestational age.
- Abnormal CS suggests PLSVC, prompting further investigation.
Introduction:
The normal coronary sinus drains venous blood from the cardiac veins to the right atrium. In some instances, the coronary sinus may be dilated due to volume or more rarely pressure overload.
Aims:
To assess the feasibility of detecting the coronary sinus in the fetus and to establish the normal values of the coronary sinus dimensions throughout gestation.
Subjects And Methods:
Fetal echocardiography was performed in 78 normal fetuses from the 16th to the 40th week of gestation (median 25 week). The coronary sinus was measured in four-chamber view (87% of cases) or in parasternal short axis view equivalent (13%). A second group of nine fetuses with a dilated coronary sinus was compared to the normal group.
Results:
Adequate imaging of coronary sinus was obtained in 97.4% of the normal fetuses. The diameter of the coronary sinus ranged from 1 to 3.2 mm (2 mm +/- 0.13 mm, mean +/- 5% confidence interval) and correlated well with the age of pregnancy (r = 0.86). The length-to-diameter ratio of 24% (+/- 6%) did not vary throughout pregnancy. All nine fetuses with a dilated coronary sinus had a persistent left superior vena cava which drained into it. The diameter of the coronary sinus was approximately three times larger in the abnormal group with a diameter-to-length ratio of approximately 83% (P < 0.0001).
Conclusion:
The coronary sinus is readily identified in the fetus. It gradually increases during pregnancy. An abnormal coronary sinus is easily diagnosed and should prompt the sonographer to look for a persistent left superior vena cava.
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