Left Atrial Appendage Aneurysm: A Rare Cardiological Challenge with Potential Viral Myocarditis Association—Innovative Endoscopic Resection and Comprehensive Literature Review

Left Atrial Appendage Aneurysm: A Rare Cardiological Challenge with Potential Viral Myocarditis Association—Innovative Endoscopic Resection and Comprehensive Literature Review | Authorea try { document.documentElement.classList.add('js'); } catch (e) { } var _gaq = _gaq || []; _gaq.push(['_setAccount', 'G-8VDV14Y67G']); _gaq.push(['_trackPageview']); (function() { var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true; ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s); })(); Skip to main content Preprints Collections Wiley Open Research IET Open Research Ecological Society of Japan All Collections About About Authorea FAQs Contact Us Quick Search anywhere Search for preprint articles, keywords, etc. Search Search ADVANCED SEARCH SCROLL This is a preprint and has not been peer reviewed. Data may be preliminary. 15 January 2025 V1 Latest version Share on Left Atrial Appendage Aneurysm: A Rare Cardiological Challenge with Potential Viral Myocarditis Association—Innovative Endoscopic Resection and Comprehensive Literature Review Authors : Raheleh Kaviani 0000-0003-2068-1969 , Seyed Shahin Eftekhari , Hamidreza Pouraliakbar , Saeid Hosseini 0000-0002-5597-7770 , Hossein Nokhbeh Zaeim , Haniyeh Faraji Azad , Ermia Tabandeh , Seyyed Mojtaba Hashemizadeh , and Zahra Emkanjoo 0000-0002-7599-5634 [email protected] Authors Info & Affiliations https://doi.org/10.22541/au.173697408.84576466/v1 589 views 267 downloads Contents Abstract Information & Authors Metrics & Citations View Options References Figures Tables Media Share Abstract Left atrial appendage aneurysm (LAAA) is a rare and often underdiagnosed cardiovascular anomaly with potentially serious complications, including arrhythmias and thromboembolic events. This report presents the case of a 36-year-old woman who developed LAAA after a recent viral respiratory infection. She presented with palpitations and atrial tachyarrhythmia, and transthoracic echocardiography (TTE) revealed a 5.6 x 3.5 cm aneurysmal left atrial appendage (LAA) with a reduced left ventricular ejection fraction of 50%. Cardiac computed tomography and cardiac magnetic resonance imaging confirmed the diagnosis, revealing a “smoky appearance” concerning blood flow dynamics and late gadolinium enhancement consistent with prior myocarditis. The patient successfully underwent minimally invasive endoscopic thoracoscopic aneurysm resection with cardiopulmonary bypass and transesophageal echocardiographic (TEE) guidance. No thrombus was found during preoperative TEE, and her postoperative recovery was smooth, with restored sinus rhythm, improved left ventricular function (55%), and no arrhythmias during follow-ups. This case highlights the crucial role of multimodal imaging, particularly echocardiography, in diagnosing and managing LAAA, while also drawing attention to a potential association with viral myocarditis. The successful use of minimally invasive surgical techniques underscores their value in optimizing outcomes for this rare condition, warranting further investigation to guide future practice. Left Atrial Appendage Aneurysm: A Rare Cardiological Challenge with Potential Viral Myocarditis Association—Innovative Endoscopic Resection and Comprehensive Literature Review Raheleh Kaviani 1* , MD; Seyed Shahin Eftekhari 2,3* , MD; Hamidreza Pouraliakbar 2 , MD; Saeid Hosseini 4 , MD; Hossein Nokhbeh Zaeim 2,3 , MD; Haniyeh Faraji Azad 1 , MD; Ermia Tabandeh 2 , MD; Seyyed Mojtaba Hashemizadeh 2,3 , MD; Zahra Emkanjoo 5** , MD 1 Echocardiography Research Center, Rajaie Cardiovascular Institute, Tehran, Iran 2 Cardiovascular Research Center, Rajaie Cardiovascular Institute, Tehran, Iran 3 Department of Cardiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran 4 Heart Valve Disease Research Center, Rajaie Cardiovascular Institute, Tehran, Iran 5 Cardiac Electrophysiology Research Center, Rajaie Cardiovascular Institute, Tehran, Iran * Note: Raheleh Kaviani and Seyed Shahin Eftekhari are joint first author of this manuscript. **Corresponding Author: Zahra Emkanjoo, MD Adress: Cardiac Electrophysiology Research Center, Rajaie Cardiovascular Institute, Tehran, Iran Email: [email protected] Phone: +982123922141 Abstract Left atrial appendage aneurysm (LAAA) is a rare and often underdiagnosed cardiovascular anomaly with potentially serious complications, including arrhythmias and thromboembolic events. This report presents the case of a 36-year-old woman who developed LAAA after a recent viral respiratory infection. She presented with palpitations and atrial tachyarrhythmia, and transthoracic echocardiography (TTE) revealed a 5.6 x 3.5 cm aneurysmal left atrial appendage (LAA) with a reduced left ventricular ejection fraction of 50%. Cardiac computed tomography and cardiac magnetic resonance imaging confirmed the diagnosis, revealing a “smoky appearance” concerning blood flow dynamics and late gadolinium enhancement consistent with prior myocarditis. The patient successfully underwent minimally invasive endoscopic thoracoscopic aneurysm resection with cardiopulmonary bypass and transesophageal echocardiographic (TEE) guidance. No thrombus was found during preoperative TEE, and her postoperative recovery was smooth, with restored sinus rhythm, improved left ventricular function (55%), and no arrhythmias during follow-ups. This case highlights the crucial role of multimodal imaging, particularly echocardiography, in diagnosing and managing LAAA, while also drawing attention to a potential association with viral myocarditis. The successful use of minimally invasive surgical techniques underscores their value in optimizing outcomes for this rare condition, warranting further investigation to guide future practice. Key word(s): Left Atrial Appendage Aneurysm, Arrhythmias, Cardiac Surgical Procedures Running title: LAAA: Imaging and Endoscopy in Rare Aneurysm Management Introduction In the fourth week of embryonic development, the left atrial appendage (LAA) formed at the left wall of the left atrium (LA) and extended between lateral and anterior of the LA as a finger like projection (1, 2). Its structure is different from the LA (1). LAA has a small role in LA compliance and so LA pressure and left ventricle (LV) filling pressure(1, 2). During the decrease of flow velocity in LAA, for example following atrial fibrillation, mitral stenosis and also increased LV filling pressure, thrombosis formation in LAA can be occurred (2). The left atrial appendage aneurysm (LAAA) is an extremely rare cardiovascular disorder that was first described by Dimond et al. in the 1960 (3). As of now, over 180 cases have been documented (1). Due to its rarity, diagnosing and forming a consensus on therapeutic approaches for LAAA remains challenging (4). Typically discovered accidentally during surgery, autopsy, or via cardiovascular imaging such as echocardiography, cardiac computed tomographic angiography (CTA), and cardiac magnetic resonance imaging (MRI) (4-6). LAAA clinical presentations range from asymptomatic to serious conditions, including cardiac arrhythmias, heart failure, thrombotic events, compression of adjacent structures, and sudden cardiac death (4). Etiologically, LAAA can be congenital due to dysplasia of the atrial pectinate muscles or pericardial defects, or acquired from mitral valve disorders, syphilis myocarditis, and tuberculosis (7, 8). Literature indicates that some aneurysms are intrapericardial, causing wall weaknesses, while others are extrapericardial (4, 6, 7). Surgical resection, often in conjunction with medical treatment, is the recommended management strategy (4, 5, 9). This report aims to highlight a rare LAAA presentation and review relevant literature to enhance understanding of diagnostic and treatment strategies. Case Presentation A 36-year-old woman, a recent smoker with a history of asthma, presented with palpitations and dyspnea, which commenced two months after a severe upper respiratory infection. Aside from a heart rate of 150 beats per minute, her vital signs were normal. Physical examination was unremarkable. An initial electrocardiogram (ECG) revealed atrial tachyarrhythmia with a 2:1 atrioventricular (AV) block that maybe originated at LA (Figure 1). Transthoracic echocardiography (TTE) showed normal LV size with mildly reduced systolic function (left ventricular ejection fraction (LVEF): 50% during tachycardia), abnormal motion of interventricular septum, normal bi-atrial sizes (left atrium volume index: 21 cc/m², right atrium volume index: 14 cc/m²), mild mitral regurgitation (MR) and small pericardial effusion. Apical 4 chamber view of TTE revealed a large outpouching adjacent to lateral side of LA with extension to lateral of LV that connected to LA with an ostium of 2.4 cm compatible with large aneurysmal LAA measuring 5.6 cm by 3.5 cm (Figure 2A, Movie 1). Communication between LA and LAA was confirmed by color doppler study in TTE that showed to and fro flow between them via ostium of aneurysm. The patient underwent cardiac multidetector CT with prospective ECG gating and high-pitch non-ECG gated delayed phase at 90 seconds using the Somatom Force (Dual Source 192x2, Siemens, Forchheim, Erlangen, Germany). The CTA also revealed a large aneurysmal LAA with a smoky appearance at the tip. No obvious clot was detected on the delayed images (Figure 3). Due to the patient’s decreased LVEF, they were referred to the imaging department for a cardiac MRI to better evaluate the myocardium and precisely measure the EF. The cardiac MRI was performed using the Magnetom SOLA (Siemens, 48 gradient channels, Forchheim, Erlangen, Germany). Calculations were done using CVi42 software (Circle Cardiovascular Imaging Inc., Calgary, Canada). The MRI confirmed a large aneurysmal LAA with a smoky appearance and no obvious filling defects. The EF was calculated from a stack of short-axis SSFP images and demonstrated a decreased EF. The late gadolinium enhancement (LGE) sequence was performed after intravenous contrast administration (0.2 mmol/kg) using DOTAREM (Guerbet, Paris, France). The LGE images showed mid-subepicardial hyperenhancement in the posterolateral segments of the left ventricle wall, suggestive of a previous episode of myocarditis (Figure 4). The procedure involved thoracoscopic resection of the LAAA using cardiopulmonary bypass (CPB), assisted by transesophageal echocardiography (TEE). Intraoperative TEE before resection showed no thrombosis in LAAA with emptying velocity: 31 cm/s. A minimal thoracic incision allowed for the identification of the aneurysm via endoscopic techniques (Figure 5). Post-pericardiotomy, the LAA was sutured in three layers, and the aneurysm was resected. Intraoperative TEE post-resection confirmed an acceptable resection of the LAAA. The patient recovered smoothly, was extubated the day post-surgery, transferred to general care by the second day, and discharged in good condition four days later. Follow-up TTE, about 2 weeks after discharge showed LVEF: 55%, mild MR and acceptable size of LAA (Figure 2B), with subsequent visits at one, three and six months later. The patient had no complaint of palpitations after surgery and had normal sinus rhythm in ECG at follow up visits. Discussion The first reported case of LAAA by Dimond involved surgical resection after angiographic confirmation in 1960 (3). Initial intraoperative diagnoses by Parmley et al. in 1962 (4, 10) were followed by advancements in imaging technology, including I-131-labeled albumin by Godwein in 1968 (11), and further refined by echocardiographic techniques in the 1980s (4, 12, 13). With the expansion of diagnostic modalities using contrast media and the subsequent development of cardiac MRI, the detection of LAA aneurysms has increased. This has enhanced our understanding of their natural history, along with the associated morbidities and mortality (5). As represented in case reports, LAAA can occur across a wide range of ages, from 28 weeks gestational age prenatally to 88 years old. However, most cases are diagnosed between the second and fourth decades of life, with an estimated 25% occurring in the third decade (4, 9, 14), similar to the case presented in this report. This may indicate that the LAA aneurysm increases in size over time (7). Some analyses show a slight preference for women, with 53% of cases in women compared to 47% in men (5, 14). As previously stated, LAA aneurysms are categorized into congenital and acquired types. The majority of cases of LAAA (approximately 90%) are congenital anomalies, which may result from dysplasia of the atrial pectinate muscle (15). However, some authors have reported associations of LAAA with congenital anomalies such as atrial septal defect, ventricular septal defect, anomalous pulmonary venous drainage, tricuspid atresia, Noonan syndrome, Hurler-Scheie syndrome, transposition of the great arteries, and, rarely, mitral valve cleft (5, 7, 15). Acquired aneurysms of the LAA may occur due to mitral valve disease, syphilis myocarditis, and tuberculosis, while association with viral infections, such as COVID-19, has also been reported (4, 15, 16). As depicted, evidence of previous myocarditis is observed in cardiac MRI through LGE in the posterior basal segment of the LV, which may be attributed to a prior viral infection. \RL Endocardial and myocardial fibrosis are known to be the most common histopathologic findings in both congenital and acquired LAAA (5). However, in some cases, myocardial hypertrophy with interstitial fibrosis has been considered as a potential finding (15). The literature describes a variety of presentations for LAA aneurysms, ranging from asymptomatic cases discovered incidentally via chest x-ray or echocardiography to ruptured LAA aneurysms and sudden cardiac death (17). Diagnosing these aneurysms can be challenging because symptoms often result from the compressive effects on adjacent structures rather than direct cardiac effects (18). The most to least prevalent symptoms associated with LAA aneurysms are palpitation (43%), dyspnea (22%), arrhythmia—mainly supraventricular tachyarrhythmia or atrial fibrillation (AF) (15%)—thromboembolic events such as cerebrovascular emboli (11%), chest pain (7%), and, very rarely, cough and hiccup (18). A crucial complication of LAAA is cerebrovascular emboli, which may occur due to blood stasis in the aneurysmal LAA as a result of AF, sometimes discovered only after a stroke event (18, 19). Despite the predisposition of LAAA to thrombus formation, recent studies show that thrombus formation is independent of aneurysm size and is related instead to cardiac arrhythmias such as AF or flutter, neck size, and low flow velocity within the aneurysm (4, 7). The case reported in this article presented with palpitation and atrial tachyarrhythmia and a 2:1 AV block (Figure 1) after a relatively severe viral respiratory infection, a presentation not previously reported. LAA velocity in pre operation TEE at operation room was 31 cm/s, but notably, no thrombus was found within the aneurysm, and no history of thromboembolic events were observed. Various modalities are used to diagnose LAAA, including chest X-ray, chest CT scan, CTA, cardiac MRI, and both TTE and TEE (5, 7). Among these, the chest X-ray is not specific and typically shows cardiomegaly, a silhouette sign in the form of a mass, and convexity of the left atrial contour (6, 7, 18). A chest CT without contrast can reveal a left atrial mass but cannot reliably distinguish between differential diagnoses such as a left atrial diverticulum, dilation of the pulmonary artery, pericardial cyst, and LAAA (5, 7). An ECG-gated CTA can resolve these uncertainties by providing better visualization to identify the aneurysmal sac and its communication with the LAA cavity, and it may reveal a compressive effect on adjacent structures (5, 20). Of all these modalities, cardiac MRI offers the highest accuracy for diagnosing LAAA, with an accuracy rate of 91% (5). In our report, the diagnosis of LAAA was suggested in TTE that confirmed by CTA and cardiac MRI (Figure 3,4). Although the most accessible and cost-effective imaging modalities is TTE but also offer high diagnostic accuracy (83.3%) for LAAA are TEE (4, 5, 7). These techniques are favored for their practical utility and relatively low cost, especially when a high level of diagnostic precision is required. The typical finding of LAAA in echocardiography is an outpouching structure related to the LAA, where the connection to the LA cavity remains intact (5). This characteristic helps distinguish LAAA from other possible anomalies, as the appendage’s continuity with the atrium is typically preserved, though the aneurysmal sac may be significantly dilated. Aryal et al. defined the dimensions of LAAA using echocardiographic measurements, where the mean diameter of the orifice was reported to be greater than 2.7 mm, the mean length was 7.08 ± 3.03 cm, and the mean width was 9.5 ± 5.75 cm (4). These measurements are significant in diagnosing LAAA as they help define the abnormal size and shape of the LAA. The presence of such abnormal sizes, especially if the orifice and the appendage’s dimensions exceed certain thresholds, would raise suspicion for an aneurysmal condition. In terms of visualization, left ventricular opacification (LVO) is considered one of the best methods for visualizing blood flow in the left-sided heart chambers, which also facilitates the detection of thrombi. This technique improves the accuracy of identifying any thrombotic formations, which is particularly important since LAAA is prone to thrombus formation due to blood stasis in the aneurysmal sac, especially in the context of atrial fibrillation (7). Contrast-mediated echocardiography has also been shown to be useful not only for detecting thrombus formation but also for guiding therapeutic decisions, such as the initiation of anticoagulation therapy or planning surgical intervention (7). As previously mentioned, the aneurysmal size in our reported case was 5.6 cm by 3.5 cm, with an ostial size of 2.4 cm. These dimensions are significant and suggest a relatively large aneurysm, which could potentially increase the risk for complications such as thrombus formation, embolism, or rupture. In our case, CT and intraoperation TEE showed no thrombus in LAAA before surgery. Monitoring the size and characteristics of the aneurysm is crucial, and contrast-enhanced echocardiography could provide valuable insight into both thrombus detection and the flow dynamics within the aneurysmal sac (7). As represented in the literature, apart from symptomatic treatment, including antiarrhythmic agents and anticoagulant drugs, there is currently no targeted medical treatment available for LAAA (17). Most authors recommend surgical treatment, specifically aneurysmectomy, as the preferred therapeutic approach, regardless of whether LAAA is symptomatic or asymptomatic (5, 14, 21, 22). A median sternotomy, with or without CPB, is the standard surgical approach often used for aneurysmectomy or excision of the LAA (17, 23). This method is particularly suitable for large aneurysms (5). We previously had a successful experience with median sternotomy accompanied by aneurysmectomy for a patient with a very large LAAA measuring 5.8 cm × 4.8 cm, with an orifice of 0.6 cm at our tertiary center (14). However, for smaller LAA aneurysms, alternative surgical approaches can be considered, including minimal endoscopic resection (Figure 5), percutaneous septal occlusion of LAAA using an occluder device, left thoracotomy with or without CPB, and off-pump tourniquet snare technique, often accompanied by TEE (14, 24). Upon reviewing the literature, we did not find any specific size thresholds for selecting the surgical method for LAAA. Therefore, based on the relatively smaller size of the LAAA in our case (5.6 cm × 3.5 cm with an ostial size of 2.4 cm) as shown in figure 2A and 5, we opted for a successful minimal endoscopic thoracoscopy with CPB to resect the left atrial appendage aneurysm and perform aneurysmectomy (Figure 5). In the absence of clear guidelines on size thresholds, it is critical to consider the individual patient’s anatomy and clinical presentation. This approach aligns with recent studies advocating for minimally invasive techniques in appropriately selected patients, as they are associated with reduced recovery times and postoperative complications (7). Atrial arrhythmias such as AF, atrial flutter (AFL), and atrial tachyarrhythmias are typically managed immediately after LAAA resection. In some cases, ablation procedures are employed to treat persistent arrhythmias (25). In our case, sinus rhythm was restored after the surgical resection of LAAA, and no ablation procedure was necessary for 6 months follow up. Overall, the postoperative complications associated with LAAA surgical management are low, and the prognosis is generally good (17). According to published studies, 5.3% of patients who underwent surgical treatment experienced postoperative thromboembolic events, and 4% of patients developed cardiac arrhythmias on follow-up, which led to the need for cardiac ablation. However, in one reported case, an adult patient passed away due to carcinoma during follow-up (14). Conclusion LAAA is a rare cardiovascular anomaly that presents both diagnostic and therapeutic challenges. This case of a young woman post-respiratory infection serves to highlight the potential for atypical presentations and the efficacy of surgical resection in managing this condition. Surgical intervention provides excellent prognosis and outcomes, emphasizing its role as the standard of care. Continued accumulation of case reports and research is critical to refine diagnostic criteria and optimize management strategies for LAAA patients. References 1. Daralammouri Y, Odeh A, Abuzahra S, Azamtta M, Shawahna R. Left atrial appendage aneurysm: a descriptive systematic review of 177 cases. BMC Cardiovascular Disorders. 2024;24(1):633.2. Beigel R, Wunderlich NC, Ho SY, Arsanjani R, Siegel RJ. The left atrial appendage: anatomy, function, and noninvasive evaluation. JACC: Cardiovascular imaging. 2014;7(12):1251-65.3. Dimond EG, Kittle CF, Voth DW. Extreme hypertrophy of the left atrial appendage: The case of the giant dog ear∗. American Journal of Cardiology. 1960;5(1):122-5.4. Aryal MR, Hakim FA, Ghimire S, Ghimire S, Giri S, Pandit A, et al. Left atrial appendage aneurysm: a systematic review of 82 cases. Echocardiography. 2014;31(10):1312-8.5. 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Congenital left atrial appendage aneurysm in a 2-year-old boy. European heart journal. 2006;27(8):959-.23. Nakai Y, Asano M, Nomura N, Mishima A. Surgical management of an aneurysm of the left atrial appendage to prevent potential sequelae. Interactive cardiovascular and thoracic surgery. 2013;17(3):586-7.24. DiBardino DJ, Aggarwal A, Knudson JD. Off-pump snare technique for congenital left atrial appendage aneurysm. Cardiology in the Young. 2014;24(3):555-8.25. Kuiten WM, de Heer LM, van Aarnhem EE, Onsea K, van Herwerden LA. Giant left atrial appendage: a rare anomaly. The Annals of thoracic surgery. 2013;96(4):1478-80. Figure 1 . ECG showing atrial tachycardia with 2:1 AV block, characterized by rapid atrial rhythm and alternate pulse transmission to the ventricles with an origin of left atrium. Figure 2 . Off axis view of apical 4-chamber in transthoracic echocardiography (A) showed LAA aneurysm with size of 5.6cm by 3.5cm (orange star) that connected to LA with 2.4 cm ostium (orange arrow) during atrial tachyarrhythmia with 2:1 AV block, (B) showed significant reduction in LAA size after surgery (yellow arrowhead) in a sinus rhythm. Figure 3: Cardiac multidirector CTImaging . (A, B, C) Multiplanar reconstruction (MPR) in axial, oblique, and sagittal views reveals a significantly enlarged left atrial appendage (LAA) (indicated by white arrows). (D, E) Volume-rendered technique (VRT) reconstructions further illustrate the prominent LAA. Figure 4. Cardiac MRI Findings . ( A ) Coronal view using steady-state free precession (SSFP) sequence highlights the enlarged LAA (white arrow). (B ) Longitudinal view of the left ventricle (LV) with SSFP sequence shows the extensive LAA (white arrow). (C ) Short-axis view with SSFP sequence confirms the presence of the large LAA. (D )Arterial phase of MR angiography demonstrates the filling of the enlarged LAA. Figure 5. Endoscopic view highlighting the precise surgical technique: (A) Identification of a left atrial appendage aneurysm (LAAA) with clear anatomical delineation; (B) Post-resection image demonstrating successful removal, preserving surrounding tissue integrity and ensuring optimal patient outcomes. Movie 1. Off axis view of apical 4-chamber in transthoracic echocardiography revealed mildly reduced ejection fraction (50%) with a large LAA connected to LA. Information & Authors Information Version history V1 Version 1 15 January 2025 Copyright This work is licensed under a Non Exclusive No Reuse License. Keywords (s): left atrial appendage aneurysm arrhythmias cardiac surgical procedures covid-19 myocarditis Authors Affiliations Raheleh Kaviani 0000-0003-2068-1969 Rajaie Cardiovascular Medical and Research Center View all articles by this author Seyed Shahin Eftekhari Rajaie Cardiovascular Medical and Research Center View all articles by this author Hamidreza Pouraliakbar Rajaie Cardiovascular Medical and Research Center View all articles by this author Saeid Hosseini 0000-0002-5597-7770 Rajaie Cardiovascular Medical and Research Center View all articles by this author Hossein Nokhbeh Zaeim Rajaie Cardiovascular Medical and Research Center View all articles by this author Haniyeh Faraji Azad Rajaie Cardiovascular Medical and Research Center View all articles by this author Ermia Tabandeh Rajaie Cardiovascular Medical and Research Center View all articles by this author Seyyed Mojtaba Hashemizadeh Rajaie Cardiovascular Medical and Research Center View all articles by this author Zahra Emkanjoo 0000-0002-7599-5634 [email protected] Rajaie Cardiovascular Medical and Research Center View all articles by this author Metrics & Citations Metrics Article Usage 589 views 267 downloads .FvxKWukQNSOunydq8rnd { width: 100px; } Citations Download citation Raheleh Kaviani, Seyed Shahin Eftekhari, Hamidreza Pouraliakbar, et al. Left Atrial Appendage Aneurysm: A Rare Cardiological Challenge with Potential Viral Myocarditis Association—Innovative Endoscopic Resection and Comprehensive Literature Review. Authorea . 15 January 2025. DOI: https://doi.org/10.22541/au.173697408.84576466/v1 If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download. For more information or tips please see 'Downloading to a citation manager' in the Help menu . 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