Sinus arrhythmia

Sinus arrhythmia is a condition in which the impulses generated by the sinoatrial node are significantly irregular, making the rhythm of the atria and ventricles irregular as well. On an electrocardiogram recorded in the same lead, the difference between the longest P-P interval and the shortest P-P interval exceeds 0.16 s (some scholars advocate exceeding 0.12 s). Patients with sinus arrhythmia generally have no specific symptoms; only when the heart rate is too low or too fast may palpitations, dizziness, or even syncope occur. Generally, sinus arrhythmia does not produce clinical symptoms, is of little clinical significance, and does not require treatment. Sinus arrhythmia often coexists with sinus bradycardia. Only sinus arrhythmia with marked sinus bradycardia requires treatment with drugs that increase heart rate, such as atropine, isoproterenol, and aminophylline. For non-respiratory sinus arrhythmia caused by heart disease or drugs, treatment should be directed at the underlying cause. Sinus arrhythmia has the following types: ① respiratory sinus arrhythmia (phasic arrhythmia); ② non-respiratory sinus arrhythmia; ③ ventriculophasic sinus arrhythmia; ④ sinus rhythm initiation phenomenon; ⑤ paired sinus rhythm and wandering pacemaker within the sinoatrial node.