The patient had a history of dilated cardiomyopathy with a left ventricle ejection fraction (LVEF) of 20%, diagnosed 4 years ago, and permanent atrial fibrillation. The patient was on enalapril, carvedilol, spironolactone, furosemide, warfarin, and omeprazole, but despite knowledge of the disease, he was on irregular use of those medications and without medical follow-up. A recent investigation for abdominal pain and treatment carried out with a gastroenterologist showed no relief.

The potential causes of right heart failure in this patient might include cardiac tamponade, pericarditis, including constrictive and tuberculosis, cardiac tumors, tricuspid valve disease, left heart failure, and even vena cava syndrome.

Upon admission, after investigation for atypical chest pain (epigastric pain), coronary origin was ruled out and it was related to liver congestion. High sensitivity troponins were within normal range, BNP was 188 pg/ml (reference value < 100 pg/mL), and GT range of 206 UI/L (reference value < 64UI/L). CT angiography computerized of the chest (Figure 2) demonstrated mediastinal lymph node enlargement, mild pericardial calcification, increased caliber in bilateral vena cava with filling failure in the lower vena cava, increased cardiac volume, in addition to a 66 x 40mm mass in the anteroinferior cardiac portion and another mass at the top of the anterior aspect, adjacent to the 40 x 30mm base vessels. An abdominal tomography was performed with an enlarged liver, blunt and regular contours, preserved density, and homogeneous contrast medium uptake, suggesting hepatic congestion. Therefore, with findings associated with systemic venous congestion.

Bedside transthoracic echocardiography revealed atypical movement of the interatrial septum, marked biatrial enlargement, mild left pleural effusion, and discreet pericardial effusion. One week later, a new transthoracic echocardiogram showed an ejection fraction of 35%, left atrium enlargement to 56mm (reference range 19-40mm), thickened pericardium associated with hypoechoic imaging, characterized by regular edges and thickened walls adjacent to the right ventricle (with a hypothesis of cyst), right ventricle with systolic dysfunction due to restricted mobility of the free wall, left ventricle with moderate systolic dysfunction, and mild mitral and tricuspid regurgitation.

To define the thoracic mass, and distinguish between cardiac and pericardial mass, magnetic resonance imaging of the heart was performed (Figure 3), which showed an LVEF of 35%, a right ventricle with signs of significant diastolic restriction associated with extrinsic compression of the free wall related to the pericardial mass, also demonstrating diffuse hypokinesia and mild systolic dysfunction, which showed an EF of 41%. Enlargement of the left chambers and right atrium. Significant pericardial thickening restricted to the region of the right atrioventricular groove, compressing the right ventricle with mass effect, without signs of flow within it and with signs of restriction suggestive of constrictive pericarditis.

After analysis of the images, constrictive pericarditis became the primary diagnostic hypothesis, and the presence of a thrombus within the pericardial mass was considered. This consideration was based on the significant enlargement of the patient's atrium, the previous history of atrial fibrillation, and a reduced ejection fraction, which together could have led to thrombus formation.

The patient was treated with diuretics and reintroduction of medications for heart failure due to its left side's known previous dysfunction, in addition to anticoagulation for atrial fibrillation and heart rate control.

The patient was referred for cardiac surgery. Pericardiectomy was performed for definitive diagnosis and treatment of right heart failure caused by the mass. At the time, adhesions related to constrictive pericarditis were removed. Postoperatively, he developed pneumonia but progressed well and was discharged two weeks after surgery. The anatomopathological examination of the pericardium demonstrated fibrous thickening, with a chronic non-granulomatous inflammatory process, with areas of dystrophic calcification, associated with signs of old and recent hemorrhage, with adhered fibrin and absence of malignancy, these results corroborated with constrictive pericarditis.

At the time of this publication, the patient is asymptomatic and without recurrences of events, using enalapril, metoprolol, furosemide, spironolactone, digoxin, dapagliflozin and rivaroxaban, undergoing regular outpatient follow-up at the cardiology service.