The diagnosis of sick sinus syndrome requires typical ECG findings such as sinus bradycardia, slow-fast syndrome, etc., and clinical symptoms associated with ECG changes. Sick sinus syndrome, known as sick sinus node syndrome, belongs to the category of arrhythmia in cardiac diseases, which is caused by the sinus node lesions leading to hypoplasia and a series of arrhythmic manifestations. Typical electrocardiographic manifestations of sick sinus syndrome include: persistent and significant sinus bradycardia (<50 beats/minute), excluding pharmacologic factors; sinus arrest, sinus block; and slow-fast syndrome, which refers to alternating episodes of bradycardia and atrial tachyarrhythmia. The diagnosis of sick sinus syndrome requires, in addition to typical ECG manifestations, proof of a clear correlation between clinical symptoms and ECG changes, which can be demonstrated by an ambulatory electrocardiogram or an event recorder, for example, if the onset of a symptom, such as syncope, coincides with the instrumentation that records the presence of bradycardia or sinus arrest in the patient. Sick sinus syndrome suggests a visit to the cardiology department to correct the cause of the symptoms, if any, under the supervision of a physician, and if necessary, to actively perform permanent pacemaker placement.