This electrocardiogram shows right ventricular enlargement + right axis deviation + right atrial enlargement.

The characteristic features of right ventricular enlargement demonstrated here include an rSR' complex and associated ST-T abnormalities in V1 and right axis deviation, reflected in part by the predominantly negative QRS complex in lead I. Right atrial enlargement is reflected by the tall narrow P waves in lead II and is commonly seen with right ventricular enlargement. An atrial level left-to-right shunt is responsible for these findings.