Sinus P waves occur regularly, with a frequency between 60 and 100 P waves per minute, a difference between P waves and P waves of < 0.12 seconds, and a PR interval > 012 seconds is considered a “normal” sinus rhythm. Beyond this range, it is called “sinus arrhythmia”. A spacing between sinus P waves and sinus P waves > 012 seconds is called sinus arrhythmia. Sinus arrhythmia and premature beats are among the most common electrocardiographic manifestations. According to the above rules, it is not wise to classify sinus arrhythmia into the range of “arrhythmia”, because the word “arrhythmia” in the diagnosis often makes the patient uneasy if the doctor does not explain patiently. In fact, the normal human heart is finely regulated by both sympathetic and parasympathetic nerves. Sympathetic excitation makes the heart beat faster and more uniformly to adapt to the body’s activities or environmental changes; vagal excitation slows the heartbeat and makes it easier for sinus arrhythmias to occur, so that the body can nurture its energy. Under the dual fine regulation of sympathetic and parasympathetic nerves, changes in breathing and body position sometimes lead to sinus arrhythmia. Sinus arrhythmias can be divided into: respiratory sinus arrhythmias, non-respiratory sinus arrhythmias, intra-sinus node wandering rhythms, and intra-atrial wandering rhythms. Among them, respiratory sinus arrhythmia accounts for most of the cases, mostly seen in normal adolescents, and is related to the excitability of the vagus nerve, mostly seen when the heart is bradycardic, and the sinus arrhythmia disappears when the breath is held. The above cases account for the majority of sinus arrhythmias. A small number of patients may have palpitations, which require patient and correct interpretation. A small number of non-respiratory sinus arrhythmias can be seen in the normal elderly, coronary artery disease, increased intracranial pressure, the effects of digitalis, morphine, etc., or structural heart disease. Sinus arrhythmias in pathological conditions are generally more severe in their degree of arrhythmia. In these types of patients, the diagnosis of the primary cause is usually clear, and severe sinus arrhythmia is only one of the external manifestations of the disease, and the treatment is only and only for the primary cause, not for the sinus arrhythmia itself. The following two facts illustrate: lack of rhythm variation, strictly uniform sinus rhythm is not normal, and the opposite evidence that most of the heart structure is normal sinus arrhythmia is not bad: 1, hyperthyroidism: fast heart rate, minimal rhythm variation, very even heartbeat, very neat rhythm, doctors and readers will not consider this “sinus rhythm The doctor and readers will not think that this “sinus rhythm” is a “normal” heart rhythm, right? 2.After acute myocardial infarction: stress state, all neuro-endocrine level is hyperactive, fast heartbeat, no rhythm variation, very neat rhythm, no sinus arrhythmia! But on a subbasis, the sudden appearance of ventricular tachycardia, ventricular fibrillation, to die. What should I do when the ECG suggests sinus arrhythmia? Follow up with an echocardiogram once a year. For young and middle-aged people, echocardiogram results that do not indicate significant structural abnormalities of the heart and simple sinus arrhythmias should not be equated with heart disease. Don’t spend money on long-term over-examination, over-explanation and over-treatment, which will affect your life and work by putting on the hat of “arrhythmia” and “heart disease” for a long time. For sinus arrhythmias with significant structural abnormalities in the heart as indicated by echocardiograms or other tests, see a cardiologist to address structural heart problems.