Arrhythmia in a 30-year-old woman may be caused by abnormal impulse formation and abnormal impulse conduction. 1. Abnormal impulse formation: including sinus arrhythmia and ectopic arrhythmia, and ectopic arrhythmia includes atrial pre-systole, junctional pre-systole, ventricular pre-systole, and atrial fibrillation. 2. Impulse conduction abnormality: including physiological causes, such as interference and interferential atrioventricular separation, and pathologic causes, including sinus atrial block, atrioventricular block, and intra-atrial block. There are many other causes of arrhythmia in a 30-year-old woman, which should be emphasized, and timely consultation should be made to identify the cause of the disease and follow the medical advice for further treatment or therapy.