Summary: New European Society of Cardiology (ESC) guidelines on heart failure diagnosis and treatment have been recently issued. The paper discusses key changes to heart failure (HF) treatment, especially in the group of HF patients with reduced ejection fraction (rEF) of left ventriclue. Major, most important changes of HFrEF include: a simplified treatment algorithm and the new drugs in class recommended therapy - SGLT2 inhibitors: dapagliflozin and empagliflozin. The 4 key drug therapies (angiotensin converting enzyme inhibitors ‒ ACE-I, beta-blockers, aldosterone antagonists and SGLT2 inhibitors) should be initiated as quickly and safely as possible. Some other tailored management is discussed. New indications for implantable cardioverter-defibrillators (ICD) and cardiac resynchronization therapy devices are presented with their new class indications. With regard to treatment of HFpEF, recommendations in the new guidelines have largely remained unchanged. The Task Force acknowledges however that the treatment options for HFpEF were being revised at the time of publication of these guidelines, so they do not include positive outcomes of EMPEROR-Preserved trial with empagliflozin. Key quality indicators have been added to monitor how we deal with HFrEF patients in daily clinical practice and the rule „5 x 100%” is also discussed in this paper according to those indicators.