Prevalence of heart failure (HF) is increasing as improved medical care has prolonged the lifespan of patients suffering heart disease. Patients with HF are often complicated by arrhythmias and at high risk of sudden cardiac death (SCD). How to prevent and treat arrhythmias and SCD in patients with HF (especially HF with reduced ejection fraction, HFrEF) is a difficult problem in clinical practice. The side effects of antiarrhythmic drugs (AAD)have greatly limited their clinical application in patients with HF and arrhythmias, and the role of drugs in preventing and treating SCD is extremely limited. In this paper, the latest views on the relationship between HF and arrhythmias in recent years and the clinical application of AAD in patients with HF will be briefly reviewed from the clinical perspective, so as to provide references for clinicians.