Evaluation of Mitral Stenosis Patients with Atrial Fibrillation for Factors Associated with Left Atrial Thrombosis

Introduction: Rheumatic heart disease still remains a common health problem and an important cause of morbidity and mortality in all age group. Mitral stenosis is the most common cardiac valve lesion involved in rheumatic heart disease. This can cause serious complications if left untreated and can lead to enlargement of the left atrium and stasis of blood which increases risk of clot formation in the left atrium and the left atrial appendage. The presence of left atrial thrombi is associated with a threefold increase in embolic events. In clinical practice we frequently come across patients of mitral stenosis with atrial fibrillation, this study will enlighten the practicing physicians about the magnitude of the problem of LA thrombus in patients with mitral stenosis having atrial fibrillation and will help them to modify their management protocol accordingly to prevent the fatal complications of Thromboembolism. Objectives: To determine the prevalence of Left Atrial thrombus in mitral stenosis patients with atrial fibrillation. To study the association of Left Atrial Size, gender, LASEC (Left Atrial Spontaneous Echo Contrast) and severity of Mitral Stenosis with LA clot formation in mitral stenosis patients with atrial fibrillation. Methods: A cross sectional descriptive type study was conducted in the Echocardiography department of the cardiology Department Lady Reading Hospital Peshawar from March 23 , 2010 to September 22, 2010. A total of 152 consecutive patients with severe and moderate Mitral stenosis (MS) and Atrial Fibrillation (AF) were included in this study. 12-lead Electrocardiography was done once clinical and echocardiographic features revealed moderate and severe MS. Patients with signs of AF were selected and both Transthoracic Echocardiography (TTE) and Transesophageal echocardiography (TEE) was performed on all patients to detect Left atrial clot. Results: Among 152patients studied; there were 65 males and 87 females. TTE and TEE was performed in all patients and TTE detected LA thrombus in 3 patients while TEE detected LA thrombus in 41 patients. Among them, 6 patients had clots in LA body while LA appendage clots were found in 32 patients. Left atrial dimension was found to be relevant (P-value = 0.004) with the presence of thrombus in patients with moderate and severe mitral stenosis associated with atrial fibrillation. Moderate MS was present in 28(18.4%) patients while severe MS was present in 124 (81.6%)patients. Female to male ratio was 1.6 but there was no statistically association with LA thrombus (P value=0.1363) . Left atrial spontaneous echo contrast (LASEC) was found in 54% and its association was statistically significant (P value <0.001) Conclusion: Left atrial thrombus was present in 27% patients with mitral stenosis associated with atrial fibrillation. All patients who underwent TTE and are found having larger LA diameter and LASEC must undergo TEE to exclude LA thrombus as TTE is having very low sensitivity for LA thrombus.