The ECG criteria for diagnosing right atrial enlargement (RAE) are as follows: The P wave amplitude in lead II > 2.5 mm, or The upward deflection of the P wave in lead V1 > 1.5 mm in amplitude.

When left atrial enlargement occurs ... Therefore, the criteria for diagnosing LAE on a 12-lead ECG is as follows: The length of the P wave in lead II is greater than 120 milliseconds OR The ...

Left atrial enlargement ... lead to blood backup from the left ventricle to the left atrium. A ventricular septal defect (VSD) is an opening or hole between the ventricles. An electrocardiogram ...