Sacubitril/valsartan is an angiotensin receptor neprilysin inhibitor with the ability to reduce myocardial hypertrophy, cardiac remodeling and cardiorenal fibrosis. The compound is also believed to have antiarrhythmic properties as it has been shown to significantly reduce ventricular arrhythmias in patients with implantable cardioverter defibrillators.

Patients suffering from heart failure with reduced ejection fraction show impaired heart rate variability, knowing that in these patients such impairment is highly associated with an increased risk of sudden cardiac death.

In its pivotal study, sacubitril/valsartan demonstrated a significant advantage over enalapril in terms of cardiovascular mortality and rehospitalization.

Against this background, this study was designed to analyze the largely unknown electrophysiological effects of sacubitril/valsartan on the autonomic cardiac nervous system by determining heart rate variability.

Inclusion Criteria:

• Patients with symptomatic severe heart failure with reduced ejection fraction (LVEF ≤40%,)
• Age > 20 years
• Consent capacity
• Sinus rhythm
• Suitable for a drug conversion from AT1/ACE inhibitors to sacubitril/ valsartan

Exclusion Criteria:

• Age < 18 years
• Atrial fibrillation
• Pregnancy
• Lack of consent capacity
• Contraindications for a therapy with sacubitril/ valsartan