A 29-year-old man presented to the hospital with progressively worsening dyspnea and palpitations for 7 years, and intermittent lower extremity edema and abdominal distension for 12 years. He denied chest pain, had no history of hypertension and diabetes, and no family history of heart disease. Personal habits included a small amount of alcohol intake and no smoking. He was diagnosed with bilharziasis, a nephrotic syndrome, approximately 10 years previously, and AF 3 years previously at a local hospital.
On admission, he was hypotensive [blood pressure (BP), 95/60 mmHg] and weak. A physical examination revealed distended jugular veins, abdominal distension, pitting edema of both lower extremities (Figure 1A), decreased breath sounds in the right lower lung, and a grade II/VI systolic murmur at the apex of the heart. Routine blood, renal function, plasma electrolyte concentration, troponin, and inflammatory and tumor marker tests were normal. He had mild liver dysfunction and elevated D-dimer (19.20 g/ml) and plasma B-type natriuretic peptide (NT-proBNP, 1,987 pg/ml). Chest radiology revealed a right-sided pleural effusion and cardiac enlargement (Figure 1B). AF [heart rate (HR), 154 bpm] without ST-segment and T-wave changes was confirmed on electrocardiography (ECG) (Figure 1C). Transthoracic echocardiography (TTE) revealed left atrial (LA) and right atrial (RA) enlargement (LA, 51 mm; RA, 53 mm), mild mitral and tricuspid regurgitation, decreased LV systolic function (LVEF, 45%), diastolic dysfunction, and a normal LV size (42 mm) (Figures 1D, E). Abdominal ultrasonography revealed a large amount of abdominal fluid, liver congestion, and inferior vena cava (IVC) distention. Pleural and abdominal effusion analyses indicated transudative fluid. Tuberculosis and rheumatism were excluded based on laboratory test results and effusion fluid analysis. Pulmonary embolism was excluded using computed tomography angiogram (CTA) (Figure 1F). Chemical cardioversion was attempted unsuccessfully using several antiarrhythmic medications (amiodarone and nifekalant). A repeat TTE revealed mitral lateral annulus e' velocity (14.4 cm/s) < mitral medial annulus e' velocity (18.4 cm/s) using tissue Doppler imaging (TDI) (Figures 2A, B). We were unable to determine significant respiratory variation of mitral and tricuspid peak E velocity due to the AF (Figure 2C). Paradoxical septal motion during respiration was not observed (Figure 2D). The IVC was dilated without inspiratory collapse (Figure 2E). The pulmonary artery pressure (~30 mmHg) was elevated according to the velocity of the tricuspid regurgitation (Figure 2F). Careful review of the echocardiographic images showed nodular thickening of the pericardium in the AV groove, without significant thickening of the whole pericardium. We then measured the peripheral venous pressure, which was elevated (43 cm H2O). These findings supported but did not confirm the diagnosis of CP. ACP was diagnosed using further CT scan analysis, which showed a thickened and calcified pericardial ring around each AV groove with minimal pericardial calcification; however, radiological pericardial thickening and calcification were not observed on chest X-ray (CXR) (Figures 3A, B). Intraoperatively, a calcified pericardial ring encircling the RV and LV cavities at the level of the AV groove was revealed. As the calcified pericardial ring was severed, spontaneous conversion to sinus rhythm was observed (Figure 3C). Pathological examination of the pericardial tissue revealed pericardial thickening, fibrous tissue hyperplasia, and hyaline degeneration, in which a large number of capillaries and few inflammatory cells were observed. A large amount of fat was observed on the surface, confirming the diagnosis of ACP (Figures 3D, E). Post-operatively, the patient's symptoms and vital signs improved significantly. The lower extremity edema, pleural effusion, and ascites subsequently subsided, and the pulmonary congestion and cardiac enlargement mitigated, indirectly indicating a reduced constrictive pattern. The patient was followed up on an outpatient basis and remained in good clinical condition. The echocardiographic assessment at the 1-month follow-up showed that the enlarged atria became smaller (LA, 39 mm; RA, 38 mm) and LV ejection fraction (LVEF) significantly improved (from 45% pre-operation to 57%). The patient management timeline during hospitalization is summarized in Table 1. This study was approved by the local Ethics Committee, and written informed consent was obtained from the patient for the publication of any potentially identifiable images or data included in this article.