A floating right atrial thrombus (RAT) is often associated with cases of massive pulmonary embolism. The etiology of RAT is diverse and includes deep vein thrombosis. The clinical implications of RAT are significant, with potential outcomes including severe complications or mortality. The management of RAT remains contentious due to the absence of standardized international guidelines. Although treatments such as anticoagulation therapy and surgical embolectomy have demonstrated efficacy, the mortality rate remains notably high, with nearly 25% of patients not surviving the condition. On the other hand, neglecting to treat RAT almost invariably leads to fatal outcomes [1] [2] .

A 63-year-old male presented to the emergency department with complaints of feeling unwell since getting out of bed. He was discharged from another hospital three days prior, having undergone a total prostatectomy for prostate cancer two weeks earlier. Postoperatively, he had been on a regimen of 4000 IU per day of prophylactic low molecular weight heparin. Since his discharge, he reported experiencing dyspnea with minimal exertion. On the morning of presentation, he experienced a presyncope upon rising from bed. A friend, who is a firefighter, advised him to seek medical attention. Upon arrival at the emergency department, the patient was conscious and appeared in relatively good general condition. History noted no cardiovascular diseases.

Regardless of the heart chambers involved, the presence of intra-cardiac thrombi is associated with pulmonary embolism (PE) in 7% of cases, according to an autopsy study published in a Swedish journal. The same study found that the prevalence of PE increases to 37% if the thrombus is in the right atrium. The diagnosis of right heart thrombus (RHT) is often made using transthoracic echocardiography (TTE), although transesophageal echocardiography (TEE) is highly sensitive. However, TEE is not often quickly available and is invasive, particularly in patients who are typically clinically unstable, which gives a major role in TTE [3] [4] . According to a study published in the European Heart Journal in 1989, echocardiography is considered an essential tool for classifying right heart thrombi. Type A thrombi are serpiginous or worm-like, highly mobile, and associated with a very poor prognosis, which was the case with our patient. Type B thrombi are relatively immobile and have a better prognosis. Type C thrombi are intermediate between the two in terms of mobility and prognosis [5] .

Although technological advances have made it possible to diagnose right atrial thrombi, treatment remains a challenge worldwide. Anticoagulation, thrombolysis, surgical embolectomy, and percutaneous retrieval techniques are the main treatment options currently available. Despite their proven efficacy in managing thromboembolic diseases, their use in RAT-associated pulmonary embolism (PE) remains perplexing and ambiguous due to the high mortality rate. However, some of these therapeutic options demonstrate superior efficacy compared to others. Fibrinolysis and surgical thrombectomy are associated with a significant reduction in mortality rates in cases of pulmonary embolism associated with RAT. Sometimes, both therapies are sequentially employed, but outcomes are not consistently positive, as cases of death still occur. This was evident in our case, where we initiated treatment with heparin therapy followed by thrombolysis. These variations in therapeutic approaches highlight the lack of international standardized consensus in the management of PE associated with RAT [1] [5] - [8] . Athappan et al. found that initial anticoagulation treatment was unsuccessful in 39.4% of cases, justifying the consideration of thrombolytics as a secondary intervention. Mortality rates are approximately 90% in untreated patients, which decrease to 18.3% with thrombolysis-based treatment and further to 13.9% with surgical intervention, according to the same meta-analysis. Thrombolysis also plays a crucial role, showing superior outcomes in hemodynamically unstable patients compared to surgical embolectomy [9] . A single-agent anticoagulation therapy was followed by pulmonary and cardiovascular complications in the case described by Rai et al. This prompts consideration that this therapeutic option may not be the optimal first-line treatment for all patients with right heart thrombus (RHT), even when they are hemodynamically stable or lack other signs of severity associated with PE in the presence of RAT [10] [11] . The current research projects are emphasizing using catheter-directed-thrombectomy and results are evidently remarkable [12] - [14] .

Right atrium thrombus is commonly associated with massive PE, presenting a significant challenge in modern medicine due to the lack of clear guidelines for its management. Research should prioritize rapid detection and early intervention because prognosis remains uncertain in many cases. Although thrombolysis and surgical approaches have shown promise in reducing mortality rates, they are still insufficient to provide definitive guidance to healthcare providers for treating patients with RAT.

1) Regardless of the presence of severe hemodynamic signs, a right atrial serpiginous thrombus is associated with pulmonary embolism, which often carries a very poor prognosis.

2) Although thrombolysis is typically indicated in cases of hemodynamic failure in PE, its use in RAT associated with PE patients can improve survival chances and especially bearing in mind that it is also reasonable to consider a surgical embolectomy.