AbstractIntroduction: view (D2 and D3), from which LA volume

AbstractIntroduction: Atrial fibrillation, the most common sustained cardiac rhythm disturbance, commonly occurs with rheumatic heart disease, particularly mitral stenosis. Hemodynamic impairment and thromboembolic events result in significant morbidity& mortality. Left atrial enlargement is one of the elements that evolve in the natural history of mitral stenosis.Objective: To determine the frequency of Atrial Fibrillation in Mitral Stenosis and to correlate it with Left Atrial Volume Study Design: Cross Sectional study Settings: Department of Cardiology, Mayo Hospital, Lahore Duration: Six months after approval of synopsis. Data Collection procedure: Standard 12 lead ECG was recorded before conducting echocardiographic study and presence of AF was documented .Echocardiographic measurements,  required for the estimation of LAV, was averaged over at least five times if the baseline rhythem is AF. All echocardiographic studies were performed by one diagnostic cardiac sonographer with the same echocardiographic instruement(VIVID 7) according to standardized protocol, that is prolate ellipse method requires measuring LA dimensions from the parasternal long-axis view (D1) and apical four-chamber view (D2 and D3), from which LA volume is calculated ( LA Volume in ml = D1xD2xD3x0.523) and biplane area-length method ( LA volume = 0.85xA1xA2/L ) interpreted by the same echocardiologist. Results:  A total of 60 patients were included in this study. Among these patients 36(60%) were male and 24(40%) were female. The male to female ratio was 3:2. Frequency of AF in patients presenting with mitral stenosis was 43.33%. mean size of LAV in patients with AF and NSR was 75.23±18.62 and 42.30±12.30. Mean MVA size for AF patients was larger as that of patients with NSR. i.e. 1.252±0.54 vs. 0.870±0.368. Moderate inverse correlation was seen between LAV and MVA in patients with AF. i.e. r=-0.436, p-value=0.010.  Conclusion:  Results of this shows high frequency for AF in patients presenting with Mitral Stenosis. Patients with AF had significantly higher Left atrial volume and Mitrial valve Area. These results may have therapeutic implication in that it may be possible with echocardiography, to identify patients in sinus rhythm, who are at high risk of developing atrial fibrillation. Prophylactic anticoagulation, antiarrhythmic therapy or both might be considered in management to prevent embolism.Key Words: Atrial Fibrillation, Normal sinus rhythm, Mitral Stenosis, Left Atrial Volume INTRODUCTIONChronic rheumatic heart disease is the commonest cause of mitral stenosis (MS).1 Incidence of rheumatic MS parallels that of acute rheumatic fever.1  Rheumatic involvement is  present in 99% of the stenotic mitral valves excised at the time of mitral valve replacement.2 Approximately 25% of all the patients with rheumatic heart disease have isolated MS and an additional 40% have combined MS and mitral regurgitation (MR).2 Two third of all the patients with rheumatic MS are women.2Atrial fibrillation (AF) develops in patients who already have ECG changes of left atrial enlargement. AF is strongly associated with left atrial size, the duration of its enlargement and the age of the patient.2-4  Enlarged left atrium due to Atrial Fibrillation prevents atrium from emptying adequately into ventricle with excess  pooling of blood  into left atrium. The dilated atrial walls  provide the ideal conditions of a long conductive  pathway as well as slow  conductance, both of which predispose to Atrial fibrillation.5Fifty to eighty percent of patients develop paroxysmal or chronic atrial fibrillation; until the ventricular rate is controlled, it may precipitate pulmonary oedema.6 Spontaneous contrast  within the left atrial cavity is probably due to stasis resulting from obstruction to forward flow, Atrial fibrillation and increased cavity size. It predisposes to increased risk of thrombus formation, systemic embolization that leads to high