INTRODUCTION
Systemic thromboembolism is a major cause of morbidity and mortality in patients of mitral stenosis (MS).1,2 Although thromboembolic events are common in patients of MS with atrial fibrillation (AF), it has also been reported in 5-15% of patients in sinus rhythm (SR).2-4 . Left atrial appendage(LAA) is the commonest site for thrombus formation and impairment of its contractility leading to stasis is an independent predictor of thromboembolic events in patients of MS.5,6.
Serken S et al 4 in an interesting study have shown that in patients of severe MS (Mitral valve area [MVA] ≤ 1.5 cm2) there is an impairment of LAA contractility to a similar extent irrespective of whether a patient is in SR or AF. However, no data is available about the prevalence of LAA hypocontractility/inactivity (defined as LAA peak emptying velocity [LAAEV] <25cm/sec) 7,8 in patients of severe MS in SR that promotes spontaneous echo contrast (SEC) formation(a precursor of thrombus) and is an independent predictor of thromboembolic events. 9,10
So, the primary aim of this study was to assess the incidence of LAA inactivity (LAAI) in patients of severe MS in sinus rhythm.
The assessment of LAAEV to detect LAAI requires transesophageal echocardiography (TEE) which is invasive, requires expertise and is not readily available. The secondary aim was to assess clinical, hematological and transthoracic echocardiographic variables that can predict presence of LAA inactivity.
Sample size: As the proportion of active and inactive LAA in patients of severe MS in SR is not known in our population, we considered inactive LAA to be present in 50% patients. Considering 50% with 10% regression on either side with 95% confidence interval (CI), we needed 96 patients to attain an adequately powered study.