2 | CASE REPORT
A 1-year-old infant was first disclosed right atrial enlargement at
the
26 weeks of gestation, but the parents were unable to provide detailed
prenatal examination data. The infant had been asymptomatic and had not
received any
echocardiography
until he got a prolonged unhealed cold and eventually developed
pneumonia accompanying with supraventricular tachycardia and dyspnea at
the local hospital. After the infection and arrhythmia were controlled
by antibiotics and digoxin, he was transferred to our hospital.
Preoperative chest X-ray showed an enlarged cardiac shadow with a
prominent right atrial contour (Figure 1A). Transthoracic
echocardiography (TTE) disclosed a giant
right
atrial aneurysmal structure measured 7.8 × 7.5 cm and a large patent
foramen ovale (PFO) (Figure 1B). The anatomical position and structure
of the tricuspid valve (TV) were normal. The right ventricle (RV) and
left atrium (LA) were compressed by the abnormal cavity, whereas
tricuspid regurgitation was minimal. The other valves and left ventricle
were normal with good systolic function. An enhanced cardiac computed
tomography scan was requested and showed a large aneurysmal dilatation
of the right atrial appendage with no internal thrombi (Figure 2). Thus,
the infant was diagnosed with a giant right atrial appendage aneurysm
complicated with a PFO and was indicated to surgery considering the
large size of RAAA, the PFO and the previous episodes of
supraventricular tachycardia and dyspnea. After induction of anesthesia,
transesophageal
echocardiography (TEE) was performed to evaluate the
RAAA
(Figure 3A) and cardiac structure. It revealed that
the
free wall of the right ventricle (RV) was compressed by the large
aneurysm (Figure 3B).
Although
blood flow in the right atrium and RAAA was slow, no thrombus was found.
Both ventricles and left atrium were of normal size and
function
(Figure 3B). TEE also revealed a large PFO and mild tricuspid
regurgitation with normal RV systolic pressure. Considering the large
aneurysm might have higher risks of bleeding and arrhythmia, the
surgeons performed the aneurysm resection under cardiopulmonary bypass
(CPB). The giant RAAA occupied almost all pericardial space (Figure 4A).
The aneurysm sac was opened, an extremely thin atrial wall was observed,
no thrombus was found and there were many tube-like structures
distributed on the inner wall during surgery (Figure 4B). The aneurysm
was resected and the PFO was closed. After weaning of CPB,
postoperative
TEE showed that the cardiac structure was normal and
the tricuspid valve functioned
normally without regurgitation or insufficiency (Figure 5A). And the
postoperative TTE dimension of the right atrial appendage showed a
decrease in right atrial size to 2.0 cm × 2.35 cm (Figure 5B). Later
pathological examination confirmed the diagnosis of RAAA (Figure 5C).
The postoperative course was uneventful and the infant was discharged on
the 5th day after the surgery. He had a full recovery without any
complications at the three-month follow-up.