[Medical Q&A] Do you know what "sinus rhythm" means in an electrocardiogram report?

Planner: Chinese Medical Association

Reviewer: Fan Yifan, Chief Physician, Beijing Chaoyang Hospital, Capital Medical University

Sinus rhythm refers to the heart rhythm formed by the excitement of the sinoatrial node. It is the normal rhythm of the heart's electrical activity, including normal frequency, rhythm and impulse conduction order. The sinoatrial node is located at the junction of the high right atrium and the superior vena cava. It is the pacemaker of the heart and has autonomy. It can regularly release impulses and control the rhythm of the heart. On the electrocardiogram, sinus rhythm usually shows normal P wave morphology, PR interval is usually 0.12 to 0.20 seconds, and heart rate is 60 to 100 beats/minute.

Sinus rhythm is not static. It may change due to many factors, forming sinus arrhythmia, mainly including sinus tachycardia, sinus bradycardia, sinus arrhythmia, sinus arrest and sinoatrial block. Under normal circumstances, sinus rhythm can ensure that the heart pumps blood effectively to meet the blood needs of various parts of the body. However, when sinus rhythm is abnormal, such as sinus tachycardia (heart rate exceeds 100 beats/minute), sinus bradycardia (heart rate is less than 60 beats/minute) or sinus arrhythmia, it may be accompanied by symptoms such as chest tightness and palpitations, and attention should be paid at this time. Sinus arrhythmia may be related to physiological factors such as strenuous exercise and emotional changes, and may also be related to myocarditis, cardiomyopathy, coronary heart disease, hyperthyroidism, anemia, cardiac conduction system diseases, etc. Therefore, for patients with sinus arrhythmia, it is recommended to seek medical attention in a timely manner. The doctor will combine symptoms, medical history and other relevant examinations, such as cardiac ultrasound, thyroid function tests, blood routine tests, etc., to comprehensively determine the cause of the disease and give corresponding treatment recommendations.