BACKGROUND Gigantic left atrium is defined in the current literature as an excessive dilatation of the left atrium above 65mm. Chronic mitral valve disease is associated with the development of thrombus in the left atrium in up to 19% of all cases of mitral insufficiency and appropriate treatment must be initiated to prevent thromboembolic events. In order to diagnose thrombi in the left atrium or left atrial appendage, various imaging methods may be used, including cardiac magnetic resonance. CASE PRESENTATION The case report describes a 73-year-old male who developed recurrent sessile thrombus on the posterior wall of the gigantic left atrium. A large thrombus was first detected following mitral valve surgery despite effective vitamin K antagonist anticoagulation therapy. Echocardiography and cardiac magnetic resonance were used within the diagnostic procedure and to monitor the treatment outcomes. Cardiac magnetic resonance was shown to be beneficial as it provided a more precise description of the intra-atrial masses located on the posterior left atrial wall, and in such situations, is of greater benefit than standard echocardiography. This led to the surgical removal of the intra-atrial mass; nevertheless, it was quickly followed by the recurrence of the thrombus. The anticoagulant therapy was adjusted and fortified by the introduction of acetylsalicylic acid and sequentially clopidogrel, but this also did not resolve the thrombus formation. Finally, employing a combination of rivaroxaban and clopidogrel resulted in partial thrombus regression. Therefore, various pathophysiological aspects of thrombus formation and used anticoagulation strategies are discussed. CONCLUSIONS We describe a unique case of a recurrent thrombus located on the posterior wall of the gigantic left atrium. Cardiac magnetic resonance was shown to be beneficial in providing a more precise description of the intra-atrial masses located on the posterior left atrial wall as compared to standard echocardiographic examination. Development of a thrombus after mitral valve surgery despite effective anticoagulant therapy and its final resolution by introducing a combination of rivaroxaban and clopidogrel highlights the complex etiopathogenesis of thrombus formation. This supports the potential use of this combination in tailoring an individual personalized therapy for patients with recurrent atrial thrombi.

中文翻译：

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有效抗凝治疗期间巨大左心房后发性血栓：病例报告。

背景技术在当前文献中，巨大的左心房定义为超过65mm的左心房过度扩张。在所有二尖瓣关闭不全病例中，高达19％的慢性二尖瓣疾病与左心房血栓的形成有关，必须开始适当的治疗以防止血栓栓塞事件。为了诊断左心房或左心耳的血栓，可以使用各种成像方法，包括心脏磁共振。病例介绍该病例报告描述了一名73岁的男性，其在巨大的左心房后壁上复发性无蒂血栓。尽管进行了有效的维生素K拮抗剂抗凝治疗，但在二尖瓣手术后首次检测到大血栓。在诊断过程中使用了超声心动图和心脏磁共振，以监测治疗结果。心脏磁共振被证明是有益的，因为它提供了对位于左后房壁上的房内肿块的更精确描述，在这种情况下，它比标准超声心动图的益处更大。这导致了外科手术切除房内肿块。然而，随后血栓复发很快。通过引入乙酰水杨酸和随后的氯吡格雷调整和加强了抗凝治疗，但是这也不能解决血栓的形成。最后，使用利伐沙班和氯吡格雷的组合导致部分血栓消退。因此，讨论了血栓形成的各种病理生理学方面和使用的抗凝策略。结论我们描述了巨大的左心房后壁复发血栓的独特情况。与标准超声心动图检查相比，心脏磁共振被证明对提供位于左后房壁上的房内肿块的更精确描述是有益的。尽管进行了有效的抗凝治疗，但二尖瓣手术后血栓的发展及其通过引入利伐沙班和氯吡格雷的组合而最终解决，这突出了血栓形成的复杂病因。这支持这种组合在为复发性心房血栓患者定制个性化治疗中的潜在用途。