For the study, patients from the Department of General Medicine and Cardiology permission will be taken. Patients admitted in the Department of General Medicine and Cardiology will be recruited for the study according to the inclusion and exclusion criteria. Informed written consent of all the participants would be taken after explaining the purpose of the study and also the about the risks/benefits of the study. Information will be collected according to the proforma made by the primary investigator along with the inputs suggested by the guide and co-guide. The information that will be collected will be the demographic details of the patient (excluding the Name), History of presenting illness, relevant past medical or surgical history, current treatment history and routine general physical and clinical examination, relevant Lab data, XRAY, ECG and Routine Echocardiography, most of the laboratory data is sent as routine investigations, so extra investigations won’t be required. Since, it is a cross sectional observational study, data will be collected from the time once from the patient in the present admission only. Patient wouldn’t be called back for the study purpose.  By this study, we are assessing the LA size and LA volume and correlating it with the etiology of atrial fibrillation and assessing the prevalence of development of atrial fibrillation, so that we can identify the etiologies where there is high risk of development of atrial fibrillation, and early intervention and aggressive management can be done to prevent the complications. Also, since this is an observational study, the patient management will be chosen by the patients treating clinician without any intervention from the investigators.