Correspondence Address: Dr. Surender Deora Department of Cardiovascular Sciences, Sheth V. S. General Hospital, Smt. N. H. L. Municipal Medical College, Gujarat University, Ahmedabad - 380 006, Gujarat India
Source of Support: None, Conflict of Interest: None
Left atrium thrombus is seen in patients with rheumatic heart disease, severe mitral stenosis and/or atrial fibrillation, but is usually immobile and located in left atrial appendage. Freely mobile thrombus is rarely seen, and the size may vary from few millimeters to centimeters. The clinical presentation varies from presyncope or syncope in a small well organized thrombus to transient ischemic attacks or stroke in large poorly organized thrombus. Management includes urgent surgical removal of thrombus with underlying valvular correction and anticoagulation.
The incidence and prevalence of rheumatic heart disease (RHD) are decreasing worldwide but still prevalent in developing countries. Left atrium (LA) thrombus is been and is usually seen in patients of RHD with severe mitral stenosis and dilated LA and/or atrial fibrillation. It is usually immobile and located in left atrial appendage and rarely extends to left atrial body. The clinical presentation mainly depends on size and consistency of thrombus and associated valvular involvement. Here, we present two varied clinical presentations of LA thrombus with different sizes and consistency.
A 26-years-old female known case of chronic RHD presented to the emergency department with a history of two episodes of syncope in last 24 h, intermittent platypnea and palpitations. On clinical examination, heart rate was varying from 110 to 130/min, blood pressure 90/70 mm Hg. 12-lead electrocardiogram revealed atrial fibrillation with fast ventricular rate. Transthoracic two-dimensional echocardiography revealed severe mitral stenosis with mitral valve orifice area (MVOA) ~0.8 cm 2 by planimetry. There was a free-floating "dancing" well organized the thrombus in LA body, which was intermittently hitting and rebounding off the mitral valve and another immobile thrombus arising from left atrial appendage [Arrow, [Figure 1] and Videos 1 and 2].
This bouncing thrombus was causing intermittent obstruction of stenotic mitral orifice thus causing the symptoms. Patient was treated medically to stabilize her hemodynamically, but had sudden cardiac arrest after few hours of admission.
Figure 1: Transthoracic two-dimensional echocardiogram in apical 4-C view (panel A) and parasternal long-axis view (panel B) revealing left atrial dumbbell shaped well organized thrombus obstructing stenotic mitral valve orifice and another immobile thrombus arising from left atrial appendage (Arrow)
A 55-year-old female known case of chronic RHD presented with progressively increasing dyspnea and palpitation for last 1-year. She had a history of recurrent transient ischemic attacks (3 episodes in last 6 months). 12-lead electrocardiogram revealed atrial fibrillation. Transthoracic two-dimensional-echocardiography and color Doppler revealed severe mitral stenosis (MVOA ~0.7 cm 2 ) by planimetry and enlarged LA filled with giant thrombus (7 cm × 5.8 cm). There was another thrombus seen arising from LA appendage and extending to LA cavity [Panel A, [Figure 2] and Videos 3 and 4]. Patient was managed medically as patient refused for early surgery. During the hospitalization, she had one more episode of transient ischemic attack with complete recovery in 6 h, but had an ischemic stroke after 24-h with right hemiparesis. Patient was managed medically and discharged in hemodynamically stable condition.
Figure 2: Transthoracic two-dimensional echocardiogram in parasternal short-axis view (panel A) and low parasternal long-axis view with color Doppler (panel B) revealing poorly organized giant thrombus in left atrial body and another immobile globular thrombus arising from left atrial appendage
Left atrium thrombus in patients with RHD is usually seen in patients with severe mitral stenosis with dilated LA and/or atrial fibrillation. It is seen in 17% of patients with severe mitral stenosis, and the risk doubles with atrial fibrillation. , Most of the thrombus are seen in LA appendage, but in 2% of cases may extend to LA body.  Free floating dumbbell shaped thrombus in LA causing intermittent platypnea and recurrent syncope is very rare clinical presentation in patients with rheumatic mitral stenosis.  Usually, the free floating thrombi are small in size, ball-shaped and have endothelial-like superficial layer which reduces the propensity to aggregate platelets and, therefore, rarely causes systemic thromboembolism.  Another important factor for reduced thromboembolism is decreased propensity of collision between the thrombus and LA wall in already dilated LA with blood stagnation. These patients more often present with presyncope or syncope associated with dyspnea and palpitation, as in our case. Dyspnea is usually on exertion and is mainly because of valvular involvement whereas platypnea (dyspnea that occurs in an upright position) is due to intermittent obstruction of stenotic mitral valve and is an alarming bell as these patients may succumb to sudden cardiac death. On the other hand, giant thrombi are soft, fragile and poorly organized and are more prone to cause systemic thromboembolism. The clinical diagnosis of LA thrombus is usually confirmed with echocardiography with transesophageal approach as the best choice. It also helps in guiding therapy designed to reduce thromboembolic risk. 
Management of these patients needs urgent surgical removal of thrombus with correction of the underlying cause and produces long-term survival of >90%.  Anticoagulation and thrombolytic therapy is not useful in the acute management and only helps in the prevention of its further progression. , Anticoagulation therapy is mainly used for stroke prophylaxis and reduces the risk of thromboembolism by 70% and may not be effective in other 30% of patients. 
The clinical presentation of patients with left atrial thrombus varies depending on its size and consistency. Patient with small well endothelialized thrombus presents with presyncope or syncope, whereas those with large poorly organized thrombus presents more often with transient ischemic attack or stroke. Management includes urgent surgical thrombus removal with underlying valvular correction and lifelong anticoagulation.
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