The Value of the Electrocardiogram in Adult Congenital Heart Disease

The electrocardiogram is the first test that is undertaken when evaluating a patient's heart. Diagnosing congenital heart disease in an adult (ACHD) can be facilitated by knowing the classical electrocardiographic (EKG) findings. These EKG findings often result from the congenital defect that prevents a part of the cardiac conduction system from occupying its normal anatomic position. When these classical EKG findings are not present, the clinician should consider alternate diagnoses. As the patient with congenital heart disease ages, with native anatomy or after surgical or device repair, the EKG can be used to assess the patient's status and to decide if and when treatment requires adjustment. This is because the electrocardiogram (EKG) can diagnose the hypertrophy or enlargement in a cardiac chamber that results from the congenital defect or anomaly and can diagnose an arrhythmia that might compromise an otherwise stable anatomy. While ACHD often involves intracardiac shunting, in many cases the abnormality only involves cardiac electrical conduction block or ventricular repolarization. These life-threatening diseases can be diagnosed with an EKG. This review will demonstrate and explain how the EKG can be used to diagnose and follow adults with congenital heart disease. When coupled with history and physical examination, the value of the EKG in ACHD will be apparent. A diagnosis can then be made or a differential diagnosis proposed, before an imaging study is ordered.