Mitral stenosis

Electrocardiogram showing the two major findings of mitral stenosis: right ventricular hypertrophy and marked left atrial abnormality (enlargement). The presence of right ventricular hypertrophy with sinus rhythm is indicated by the tall R in V1 (as part of a qR complex) with right axis deviation. Incomplete right bundle branch block is also seen as evidenced by the rsR' in lead V2, and the prominent S waves in leads V5 and V6 with normal QRS duration. The large negative component of the P wave in lead VI (an anterior-posterior lead) indicates left atrial enlargement; the tall (>2.5 mm) P wave in lead II suggests concurrent right atrial enlargement due, in this case, to secondary pulmonary hypertension. The ST and T wave abnormalities are nonspecific. Electrocardiographic signs of right ventricular hypertrophy with atrial fibrillation also raise strong consideration of mitral stenosis.