Quick Fire Cases
Michelle Udine, MD
Advanced Imaging Cardiologist
Children's National Medical Center
Jennifer Klein, MD, MPH
Fetal Cardiologist, Assistant Professor of Pediatrics
Children's National Hospital
Vasupradha Suresh Kumar, MD
Pediatric Cardiology Fellow
Children's National Hospital
Ravi Vamsee Vegulla, MD
Assistant Professor of Pediatrics
Children's National Medical Center
Sarah E. Kollar, DO
Advanced Imaging Cardiologist
Children's National Hospital
Seiji Ito, MD
Children's National Medical Center
Yue-Hin Loke, MD
Associate Professor
Children's National Medical Center
Mary Donofrio, MD
Children's National Medical Center
.jpg "Uyen Truong, MD photo")
Uyen Truong, MD
Associate Professor
Children's National Hospital
A 33-year-old G1P0 presented at 30 weeks gestation for fetal echocardiography, with referral for a dilated left atrium. Fetal echocardiogram demonstrated a dilated left atrium, dilated right superior vena cava and innominate vein, with an open foramen ovale and normal right to left flow. Follow up fetal echocardiography at 34 weeks gestation was concerning for an intact atrial septum, worsening dilation of the left atrium and superior vena cava, and likely right superior vena cava to left atrium. A fetal cardiac MRI (CMR) and postnatal CMR were performed. The diagnosis of a right superior vena cava to left atrium and intact atrial septum was demonstrated. Fetal MRI showed a dilated innominate vein and bilateral jugular veins with no evidence of arteriovenous malformation. Delivery plan was for induction at 39 weeks gestation and transfer to the cardiac intensive care unit for possible severe hypoxia postnatally. The baby was hypoxic at birth requiring intubation followed by persistent non-invasive respiratory support. The baby underwent a modified Warden procedure and was discharged home within one week.
Diagnostic Techniques and Their Most Important Findings:
A fetal CMR was performed at 34 weeks gestation with the Northh Medical Doppler ultrasound device for fetal cardiac gating. Cine bSSFP images with maternal breath holds were performed on a Siemens 1.5T scanner with 5 mm slice thickness, FoV 300 mm, TR 37.05 ms, flip angle of 58, voxel size 1.6 x 1.6 mm, and 2 signal averages. Figure 1a demonstrates a dilated left atrium and left ventricle. Figure 1b-1d show the course of the dilated right superior vena cava that drains to the leftward aspect of the atrial septum into the left atrium, with a normal rightward position in the three-vessel view. Figure 1e shows a dilated innominate vein superior to the three-vessel view. 1f shows a coronal image of right superior vena cava draining to the left atrium. Figure 1g shows a normal three chamber view with a normal mitral and aortic valve. There was no evidence of arteriovenous malformations in the brain or neck. Postnatal CMR was performed including a Ferumoxytol-enhanced whole heart 4D flow sequence (Figure 2) that confirmed no evidence of arteriovenous malformation, a right superior vena cava to the left atrium, dilated innominate and bilateral jugular veins, with Qp/Qs=0.3:1, small pulmonary artery and veins, and reduced pulmonary blood flow.
Learning Points from this Case:
Differential diagnosis for a dilated left atrium in the fetus includes right superior vena cava to the left atrium. Fetal CMR can be used for the evaluation of systemic venous anomalies in the third trimester with cine bSSFP images in the axial plane showing the course of the superior vena cava entering on the leftward side of the atrial septum. This is particularly helpful when ultrasound images are unclear or to further define the course. Right superior vena cava to left atrium with an intact atrial septum can present with hypoxia after birth and requires delivery planning to a tertiary care center with the ability to perform neonatal cardiac surgery.
