Hrev_master Emergency Care Journal 2024; volume 20:12724 [Emergency Care Journal 2024; 20:12724] [page 111] A common complaint does not always mean a common diagnosis Francesco Cavaleri, Lorenzo Porta, Erika Poggiali Emergency Medicine Unit, Fatebenefratelli Hospital, ASST Fatebenefratelli Sacco, Milan, Italy Question What is the most likely diagnosis? 1. Constrictive pericarditis 2. Pulmonary embolism 3. Right coronary artery-coronary sinus fistula 4. Cardiogenic pulmonary edema Answer An urgent contrast-enhanced cardiac Computed Tomography (CT) confirmed the diffuse pericardial effusion (max 5 cm) without leakage of contrast media into the pericardial space and showed an arteriovenous fistula between the Right Coronary Artery (RCA) and the magna cardiac vein with the coronary venous sinus. It also confirmed a vascular sac of about 6x6x7 cm, supplied in the arte- rial phase by the RCA, which has a tortuous course and a caliber An 83-year-old woman was referred to our Emergency Department (ED) for a chronic pericardial effusion with exer- tional dyspnoea that had been worse over the past several days. She denied any chest pain, syncope, fever, or leg swelling. She suffered from hypertension, heart failure NYHA I, diabetes mel- litus type 2, and essential tremor treated with carvedilol, furosemide, olmesartan-hydrochlorothiazide, acetylsalicylic acid, and dapagliflozin. Her physical examination revealed no abnor- malities. Her vital signs were blood pressure 130/70 mmHg, heart rate 70 bpm, peripheral oxygen saturation 95% in room ambient, and respiratory rate 18/min. Laboratory findings, including C-reactive protein and troponin T, were in the normal range. The electrocardiogram showed a sinus rhythm with nor- mal atrioventricular conduction and ventricular repolarization. Point-of-care ultrasound documented an A-line pattern without pleural effusion and a diffuse and large (30 mm fluid strip) peri- cardial effusion without signs of cardiac tamponade and unchanged from the previous echocardiogram (Video 1). It also showed a large pulsing mass 6x6 cm close to the right atrium with a predominant systolic flow (Video 2, Video 3). Correspondence: Erika Poggiali, Emergency Medicine Unit, Fatebenefratelli Hospital, ASST Fatebenefratelli Sacco, Milan, Italy. E-mail: poggiali.erika@gmail.com Key words: pericardial effusion, dyspnoea, coronary artery fistula, point-of-care ultrasound. Contributions: FC and EP collected details of the case and drafted the manuscript. LP cared for the patient and critically revised the manuscript. All the authors approved the final version and agreed to be held accountable for all aspects of the work. Conflicts of interest: EP is a member of the Editorial Board of ECJ. Funding: none. Availability of data and materials: all data underlying the findings are fully available upon reasonable request to Francesco Cavaleri (francesco.cavaleri@asst-fbf-sacco.it). Ethics approval and consent to participate: as this was a descriptive case report and data was collected without patient identifiers, ethics approval was not required under our hospital’s Institutional Review Board guidelines. Informed consent: the patient provided consent for the access to medical records at the time of admission. Received: 15 June 2024. Accepted: 16 June 2024. Early view: 29 June 2024. This work is licensed under a Creative Commons Attribution 4.0 License (by-nc 4.0). ©Copyright: the Author(s), 2024 Licensee PAGEPress, Italy Emergency Care Journal 2024; 20:12724 doi:10.4081/ecj.2024.12724 Publisher's note: all claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher. Non -co mmerc ial us e o nly of about 9 mm, well opacified in the venous phase. The left atrium was compressed in the absence of thrombotic formations. Coronary Artery Fistula (CAF) is a rare congenital heart disease with an incidence of 0.002% in the general population.1 It is defined as an anomalous connection between a coronary artery and any other cardiac vessels or cardiac chambers. Most CAFs involve the RCA draining into the right heart structures.2 Although the pre- sentation may initially be asymptomatic, untreated CAFs may lead to sequelae in early adulthood, such as proximal aneurysmal dila- tion of the involved vessels, myocardial ischemia, refractory angi- na, and congestive heart failure.3 In very few cases, CAF can cause an unexplained chronic pericardial effusion4 that rarely evolves in cardiac tamponade.5 The definitive treatment requires a percuta- neous or surgical intervention.6 In our case, considering the patient’s advanced age and the high risk of an intervention to cor- rect the coronary fistula, the cardiothoracic surgeon indicated a conservative treatment with close echocardiographic and clinical monitoring. Shortness of breath is a common complaint among patients presenting to the ED. The etiology of this symptom is extremely varied, and the diagnosis often requires a specific diag- nostic work-up. Only 1% of patients with unexplained dyspnea have a pericardial effusion requiring drainage.7 References 1. Dodge-Khatami A, Mavroudis C, Backer CL. Congenital Heart Surgery Nomenclature and Database Project: anomalies of the coronary arteries. Ann Thorac Surg 2000;69:S270-97. 2. Liu J, Konda S. Operative approach for right coronary artery to coronary sinus fistula. Proc (Bayl Univ Med Cent) 2020;33:276-7. 3. Stefanescu Schmidt AC, Redwood T, Alonso-Gonzalez R, et al. An unusual pair: coronary artery fistula and coronary sinus ostium stenosis as a cause of refractory angina. Eur Heart J Case Rep 2022;6:ytac121. 4. Ozeki S, Utsunomiya T, Kishi T, et al. Coronary arteriovenous fistula presenting as chronic pericardial effusion. Circ J 2002;66:779-82. 5. Habermann JH, Howard ML, Johnson ES. Rupture of the coro- nary sinus with hemopericardium. A rare complication of coro- nary arteriovenous fistula. Circulation 1963;28:1143-4. 6. Baumgartner H, De Backer J, Babu-Narayan SV, et al. 2020 ESC Guidelines for the management of adult congenital heart disease. Eur Heart J 2021;42:563-645. 7. Blaivas M. Incidence of pericardial effusion in patients pre- senting to the emergency department with unexplained dysp- nea. Acad Emerg Med 2001;8:1143-6. Images in emergency [page 112] [Emergency Care Journal 2024; 20:12724] Online supplementary materials: Video 1. Missing title Video 2 . Missing title Video 3. Missing title Non -co mmerc ial us e o nly