due to ASD; because MS can be caused by several things, there is no exact mechanism but many mechanisms or causes. If mitral valve stenosis is a result of birth defects during development stemming from rheumatic fever, several things may occur in the heart. Rheumatic fever causes the immune system to attack its own protein tissues leading to lesions forming on the mitral valve flaps. As the flaps heals over time, the flaps lose their filmy and floppiness resulting in solid, stiff flaps. The loss of proper flappy mitral valves makes it harder for the valves to open and allow blood to flow through. As a result of blood flow being stopped or slowed by the faulty valve, pressure begins to build in the heart. It was once thought an ASD is not already present, could form because of MS, but it is now thought the ASD is either a birth defect or acquired from surgical procedures. Overall, Lutembacher's syndrome has no certain mechanism but a combination as the result of ASD and MS. Diagnosis Lutembacher's syndrome is diagnosis primarily by physical examinations for heart sounds, electrocardiograms, chest radiogram, transthoracic or transesophageal echocardiography, color flow mapping, and Doppler imaging. Use of the various test can help to differentiate other possible conditions such as mitral regurgitation, Ebstein disease, ventricular septal defect (VSD). Physical examinations A physical examination will be done to check for abnormal heart sounds, condition of heart, blood pressure, lungs, palpitations, edema, weight gain, ascites, or any other abnormal symptoms. Blood may also be drawn to help determine the cause of fatigue, determination of ascites, other health problems that maybe closely related to cause the symptoms such as kidney, liver, immune (signs of rheumatic fever), abnormal glucose levels. Electrocardiograms Electrocardiogram (ECG) is used for determination of the location, size, direction of blood flow through the atrial hole, hemodynamic of the right ventricle (blood circulation), tricuspid valve, and functioning of left ventricle. The ECG can also be used to determine the rhythm of the heart to determine if there is an indication of sinus rhythm or atrial fibrillation. In the ECG, the p wave morphology will be study for any abnormalities. If during the ECG, the P-wave (atrial depolarization) is tall, broad, or split waves in lead II and accompanied with a deep negative force in V1, this would be considered to be abnormal; only one wave should be associated