More than 2,000 years ago, the Yellow Emperor’s Classic of Internal Medicine proposed that “the superior physician treats the untreated”, and in modern society, disease prevention often has a greater impact on a person’s health. In the case of atrial fibrillation (AF), more and more people are concerned: Can AF be prevented? How does atrial fibrillation occur? Electrophysiological and structural changes in the atria occur in response to age, pre-existing disease, and environmental factors, along with changes in the metabolism and autonomic nervous system function of the atria. In this process, many factors such as inflammation, myocardial stretch, repeated oxidative stress and apoptosis are involved, and the atrial structure continues to remodel. If we can target the factors that promote atrial fibrillation and block or delay the occurrence and persistence of atrial fibrillation during the above process, we can truly prevent atrial fibrillation. Traditional treatments for atrial fibrillation, such as antiarrhythmic drugs and radiofrequency ablation, only target the electrical activity of the atria. In recent years, in-depth studies on the pathogenesis of atrial fibrillation have provided a new avenue for the treatment of atrial fibrillation. Some animal tests and clinical studies have found that some non-antiarrhythmic drugs used in specific populations can reduce the susceptibility to atrial fibrillation by changing the atrial matrix, or can prevent the occurrence of atrial fibrillation and delay the progression of atrial fibrillation, which is called upstream therapy for atrial fibrillation. 2010 European Society of Cardiology (ESC) officially recognized it as a new strategy and method for the treatment of atrial fibrillation for the first time. Atrial fibrillation upstream therapeutic agents include angiotensin-converting enzyme inhibitors (ACEI, such as somepril class), angiotensin receptor antagonists (ARB, such as somesartan class), aldosterone antagonists (such as spironolactone), statins and ω-3 polyunsaturated fatty acids, which can reduce atrial fibrosis, anti-inflammatory, anti-oxidative stress, and alter ion channel conductivity, thus improving atrial electrophysiology and structural remodeling. Use in patients who do not have AF but have risk factors for AF, such as the presence of hypertension, heart failure, or after cardiac surgery, may delay or prevent the first occurrence of AF (primary prophylaxis); use in patients who already have AF to reduce possible triggering mechanisms and thereby reduce the recurrence of AF or to stop its progression to permanent AF (secondary prophylaxis). However, based on the available clinical trial data, not everyone will benefit from upstream treatment of AF, and only some specific populations, especially those who choose appropriate upstream treatment before the onset of AF, will be able to realize its positive effects. For those who have already developed AF, the role of upstream therapy is clearly unsatisfactory. Some drugs are theoretically able to improve atrial remodeling, but the results of large clinical trials remain controversial, and therefore the authoritative AF management guidelines do not make relevant recommendations for those who have already developed AF. How to prevent atrial fibrillation? 1. Avoid heavy alcohol consumption, excessive exercise, emotional excitement, smoking, and overexertion. 2, control diabetes, obesity, chronic lung disease, sleep apnea syndrome (snoring) and other risk factors. 3.Actively treat primary diseases such as coronary heart disease, rheumatic heart disease, heart failure, cardiomyopathy and hyperthyroidism. 4.Patients with heart failure with decreased left ventricular ejection fraction (LVEF) and patients with hypertension can use ACEI or ARB to prevent new-onset atrial fibrillation. 5, For patients after cardiac bypass surgery, statin can be used to prevent new-onset atrial fibrillation. 6, In patients without cardiovascular disease, ACEI, ARB or statin is not recommended for the prevention of atrial fibrillation. In fact, changes in the atrial matrix have already begun before the onset of atrial fibrillation, and once atrial fibrillation occurs, the role of upstream therapy is very limited, and no reliable drug capable of reversing atrial fibrillation has yet emerged. Therefore, the treatment of atrial fibrillation should not only be seen and done, but more importantly, it should be traced back to the source and prepared for a rainy day, before the onset of atrial fibrillation, it should be actively prevented and prepared for a rainy day!