The main hypothesis is that autonomic dysfunction cannot improve among patients reaching end-stage heart failure. To evaluate this, patients admitted with acute decompensated heart failure in Bispebjerg hospital, and history one or more admissions with the same condition within the prior year, will undergo repeated brief heart monitoring (10 min). Baseline recordings (at admission) will be compared with equivalent measurements before discharge to explore whether heart rate variability increases. Patients will be followed for six months after discharge from the hospital.

If the patient accepts to participate and signed the project informed consent, their clinical record will be followed until the last patient included has been followed for six months.

Inclusion Criteria:

• 18-years age or older
• admitted with acute decompensated heart failure for less than 48 h

Exclusion Criteria:

• pacemaker
• not signed informed consent
• other heart rhythm than sinus rhythm or atrial fibrillation

Patients admitted to the hospital with acute decompensated heart failure, regardless of measured left ventricle ejection fraction.

Patients will be grouped according to rhythm: sinus rhythm and atrial fibrillation.