A 26-year-old female presented with symptoms of awareness of heartbeat, easy fatigue, and exertional dyspnea since childhood, with worsening of symptoms for the past 6 months. She was diagnosed with type 1 diabetes mellitus 1 year before presentation. Her gynecological history revealed she had one successful vaginal delivery and 3 spontaneous abortions.
On examination, she was tachypneic with oxygen saturation of 77% on room air, an irregular pulse rate of 85 beats per minute, and a normal blood pressure of 113/77 mmHg. She had distended neck veins with positive hepatojugular reflux. There were multiple pulsations visible over the third intercostal space right of the sternal border and the sixth intercostal space left of the sternal border with parasternal heave. Systolic and diastolic murmurs were heard all over the chest. She had epigastric distension with palpable, tender mass of around 8 cm extending below the left subcostal margin.
On her electrocardiogram, she had atrial fibrillation (Figure 1). A transthoracic echocardiogram showed a common atrium with a large atrial septal defect (Figure 2). She had severe mitral and tricuspid regurgitation with moderate aortic regurgitation, and an elevated right ventricular systolic pressure of 168 mmHg.
The chest computed tomography (CT) showed the cardiac apex directed toward the left, with both cardiac atria having the morphology of the left atrium. There is a large atrial septal defect resulting in a common atrium (Figures 3 and 4). The left and right ventricles are in a normal position with a possible atrioventricular canal defect. The left superior vena cava drains via the coronary sinus, and the inferior vena cava, residing near the midline, drains into the common cardiac atrium. The common ostium of the left pulmonary vein drains into the posterior cardiac atrium (Figure 5), while the right superior and inferior pulmonary veins drain into the anterior cardiac atrium. The aortic arch is toward the right (Figure 6). The origin of the left main coronary artery is visible and arises from the left coronary cusp. The right coronary artery is not visible. There are 2 vessel arches; the first vessel is a dominant right common carotid and the second is a right subclavian artery that produces a dominant right vertebral artery (Figure 7). The left common carotid and left subclavian arteries do not arise from the arch and are supplied via a small tortuous vessel arising from the proximal descending aorta at the level of T4-T5, which courses superiorly across the midline. As a result, the left common carotid, subclavian, and vertebral arteries are diminutive. The trachea is midline, and both the lungs are bilobed with a hyperarterial location of the airways relative to the pulmonary arteries.
The abdominal CT showed the liver is midline (Figure 8), and there are clustered foci of splenic tissue in the right upper quadrant consistent with polysplenia (Figure 9). The stomach resides underneath the right hemidiaphragm. All of the small bowel loops reside in the left abdomen and colon on the right, consistent with bowel malrotation. Highly vascular adrenal glands are observed to the right and left of the abdominal aorta, which appears fused (Figure 8). Duplicated inferior vena cava with hemiazygos continuation.
As a result, a diagnosis of heterotaxy syndrome with left isomerism was made. She was kept on sildenafil 25 mg once daily, spironolactone 25 mg once daily, digoxin 0.25 mg once daily, furosemide 40 mg once daily, and basal insulin. Additionally, bisoprolol 5 mg once daily was added later on follow-up, and continuous counseling was done over her medication use, lifestyle changes, and regular follow-up. The option of surgery was brought up, but due to the risk of complications, the patient opted out of the surgery.