An EKG is a standard method of evaluating a patient with cardiomegaly. It can help to determine the cause, severity, and the specific chamber which is affected. A q wave would indicate an area of muscle death accounting for the enlargement, and ST elevation may suggest a myocardial infarction, myocarditis or pericarditis.

• The presence of q waves suggest a prior MI to account for the enlargement.
• ST segment elevation would suggest either ongoing or resolving ST elevation myocardial infarction or myocarditis or pericarditis.
• The EKG may suggest signs of left atrial enlargement, right atrial enlargement or right axis deviation which may point toward a specific diagnosis.

• Shown below is an image of an EKG depicting right atrial enlargement.

• Shown below is an image of an EKG depicting biatrial enlargement.