This electrocardiogram shows biventricular hypertrophy and left atrial enlargement.
The characteristic features of left atrial enlargement demonstrated here include broad, notched P waves in leads I, II, V4, V6 and V7, as well as a deep, negative terminal P wave component in leads V3R and V1.
The characteristic feature of right ventricular hypertrophy include tall, dominant R waves in precordial leads V3R and V1.
The characteristic feature of left ventricular hypertrophy demonstrated here in the presence of right ventricular hypertrophy, is tall R waves in the left precordial leads.
Biventricular hypertrophy also is indicated by the large, biphasic RS complexes in mid precordial leads V2 and V4.
A large ventricular septal defect allows equal pressures in the two ventricles. This produces right ventricular hypertrophy with some dilation and both dilation and hypertrophy of the left ventricle. In the presence of normal pulmonary vascular resistance, shunt flow will be large, thereby, causing left atrial enlargement.