Many people, especially young people, have reported a “sinus arrhythmia” or even just “sinus rhythm” in their physical examination report, and because they cannot get a good explanation, they think it is some kind of heart disease, so they take time off work, make arrangements, register, wait in line, worry. …the doctor often just says: normal is fine, but then maybe you’re still worried. The heart is a large muscle, it needs to be “electrified” for a contraction and a diastolic movement, and the conduction tissue in the heart is the so-called “wire”. Each contraction of the whole heart muscle is actually an electric current from the heart, and the origin of this biological current, under normal circumstances, comes from the “sinus node”, and we call this heart rhythm from the sinus node: sinus rhythm. When the bio-current does not originate from the sinus node for some pathological reasons, it is not a sinus rhythm and is abnormal. The heart beats from one beat to the next, usually in a regular rhythm. Sometimes, mostly in young people and infants, the heart beats less regularly, but the bioelectric current still originates from the sinus node, which is called sinus arrhythmia. In general, sinus arrhythmias can be associated with respiration or can simply result from the pacing position wandering in the sinus node and are asymptomatic and not clinically significant.