CASE PRESENTATION
This is a case of a 66-year-old man with a previous history of hypertension, diabetes, chronic kidney disease, and psoriasis. He presented to the communicable disease center (CDC) with a three-day history of fever, cough, and shortness of breath. On admission, his vital signs were as follows: blood pressure:115/52mmHg, heart rate: 75 b/min, respiratory rate: 20 b/min, and oxygen saturation (O2sat): 93% on room air. His body mass index (BMI) was 29 kg/m2. Physical examination was remarkable for bilateral chest crackles with normal cardiovascular examination.
His electrocardiogram (ECG) revealed a sinus rhythm with right bundle branch block (RBBB) and left axis deviation. Chest x-ray showed patchy peripheral ground-glass opacities in both lungs and soft consolidations in the right middle lobe. Polymerase chain reaction (PCR) was performed on a nasopharyngeal swab and returned positive for SARS-CoV‑2. In addition, blood tests showed WBC of 5.9 x10^3/uL, hemoglobin of 10 gm/dL(N{13-17 gm/dL}), C‑reactive protein (CRP) of 146 mg/L [N < 6 mg/L]), ferritin of 2619 ug/L [N < 553 ug/L]), creatinine of 190 umol/L (N{62-106 umol/L), and D Dimer of 2.3 mg/L FEU [N < 0.5 mg/L FEU]).
He was started on oxygen therapy at 2 liters per minute via nasal cannula, but shortly after admission, he became severely hypoxic, and then, he was transferred to the medical intensive care unit (MICU) and kept on continuous positive airway pressure (CPAP) to maintain oxygen saturation of 95%.
Transthoracic echocardiography (TTE) was performed, which revealed normal biventricular size and function with no significant valvular disease. Mild pulmonary hypertension with an estimated systolic pulmonary artery pressure of 48mmHg was noted. The study showed echo dense mass located on the right atrial (RA) roof, best seen in four-chamber view. There was another echo-lucent mass in the RA and protruding into the tricuspid valve annulus, best seen in the RV inflow view, as shown in (Figure 1). A prior TTE report that had been performed in another center one month ago revealed no interatrial mass.
Because of acute COVID-19 pneumonia and elevated D-dimer, the RA mass was considered and treated as a thrombus. He was started on a therapeutic dose of intravenous heparin and warfarin; thus, the INR was maintained in the therapeutic range between 2 to 3. Repeated echo did not show any significant differences. For a better assessment of the RA mass, Transesophageal echocardiography (TEE) was planned, but was not performed due to acute respiratory distress with low oxygen saturation. Instead, 12 days later, upon clinical recovery a cardiac magnetic resonance imaging (CMR) was performed.
The images were obtained on a 1.5 Tesla scanner (Philips Ingenia), and findings from the multiple stacks of cine four-chamber views confirmed the presence of a structure on the posterior wall of the RA that extends onto the thickened interatrial septum (Figure 2). This smooth structure moved during systole and diastole and was identified as crista terminalis, which was rather prominent. T1 and T2 weighted images on the axial plane of this structure had a similar signal intensity to the subcutaneous fat revealing it as predominantly fatty deposition. T1 weighted images with fat saturation sequences (Figure 3) demonstrated the suppression of fatty signals consistent with LHIAS of the thickened interatrial septum associated with fatty deposition in the crista terminalis. On post gadolinium, early and late acquisition, there were no uptake or features to suggest the presence of thrombus or any other cardiac tumors (Figure 4).
CMR concluded that the prominent RA mass was lipomatosis hypertrophy of the interatrial septum, which extends to the crista terminalis with no evidence of any thrombus. Hence the anticoagulation was discontinued, and patient was discharged home in very good condition.