Exacerbation of chronic heart failure (HF) is the most common cause of hospitalization in adults, which is associated with high morbidity and mortality rates, mainly due to HF exacerbation or sudden cardiac death (SCD). A novelty in the treatment of HF with reduced left ventricular ejection fraction (HFrEF) in recent years has been the approval of sacubitril / valsartan, a drug belonging to angiotensin receptor-neprilysin inhibitors (ARNIs). Sacubitril / valsartan significantly reduces the severity of HF symptoms as well as the risk of hospitalization and death and is characterized by a good safety profile. Therefore, it has a strong position in the guidelines of international cardiac societies. However, the precise mechanism underlying the beneficial effects of ARNIs on cardiovascular mortality is unknown. The advantages of ARNIs are likely to result from improved left ventricular ejection fraction, reduced myocardial remodeling, and increased natriuretic peptide availability. Therefore, sacubitril / valsartan may exhibit antiarrhythmic properties and reduce the risk of ventricular arrhythmias and SCD in patients with HFrEF. Importantly, the improvement of the function and electrical stabilization of cardiomyocytes may translate into a reduced risk of appropriate and inappropriate implantable cardioverter‑defibrillator interventions and improvement in the percentage of biventricular pacing. In this expert opinion of the Heart Rhythm and Heart Failure Sections of the Polish Cardiac Society, we summarize and discuss the current knowledge on the effect of sacubitril / valsartan on the occurrence of ventricular arrhythmias and the risk of SCD in patients with chronic HFrEF.