A normal EKG does not mean that the heart is fine; an EKG is only one method in the diagnosis of heart disease. For structural heart disease cardiac ultrasound is of greater value. Electrocardiogram (ECG), as a commonly used diagnostic test for heart disease, is generally used to observe the presence of various arrhythmias, such as atrial premature beats, ventricular premature beats, atrial fibrillation, and acute ST-segment elevation myocardial infarction, which is of great significance in the diagnosis of arrhythmias and infarction. However, ECG is not valuable for structural changes of the heart and congenital heart disease, which need to be clarified by cardiac ultrasound. For example, in the presence of heart valve disease, the electrocardiogram is completely normal, but the heart has structural lesions. Therefore, it is important to confirm the diagnosis by selecting the appropriate tests according to the patient’s clinical presentation. It is recommended that if discomfort exists, early medical attention should be sought to avoid delaying the condition.