How does the normal heart work? Part 2

Your heart is made up of four chambers, two chambers on the right side and two on the left. The walls of these chambers are made of special heart muscle. The small chambers at the top of your heart are called atria and the large chambers below are called ventricles. Each ventricle has one valve at its entrance and one at its exit to prevent blood from flowing backwards through the heart.

Your atria and ventricles work together by alternately contracting (systole or systolic phase), to push blood out of the heart, and relaxing (diastole or diastolic phase), to fill with blood. At the start of each heartbeat a tiny electrical signal near the top of the heart spreads through your heart muscle making it contract. The atria contract first, pushing blood through the open valve into the ventricle. The electrical impulse then travels into the muscle of the ventricle, making it contract and push blood out of your heart to your lungs and body. As the ventricles contract the atria relax, allowing them to fill with blood and start the next beat.

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ESC Guidelines for Heart Failure

What patients need to know

This guide for patients from the European Society of Cardiology aims to provide an overview of the latest evidence-based recommendations for the diagnosis and treatment of heart failure.

In particular, it should help patients to understand the:

  • main types of heart failure
  • medicines used to treat heart failure
  • devices that may be appropriate
  • importance of rehabilitation
  • management by a multidisciplinary team
  • importance of self-care in managing your own condition

Learn more


A series of 9 simple, captivating animations explaining heart failure and its treatment.

These narrated animations explain how a healthy heart works, what happens to it in heart failure and how various treatments work to improve your health.


In this section you can watch, listen or read interviews with other people with heart failure and their caregivers.


and share your own views and experiences with other patients, families and caregivers. is a European Society of Cardiology website

The website was developed under the direction of the Heart Failure Association of the European Society of Cardiology (ESC). The ESC is a world leader in the discovery and dissemination of best practices in cardiovascular medicine. Our members and decision-makers are healthcare professionals who volunteer their time and expertise to represent professionals in the field of cardiology in Europe and beyond.

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