To understand many heart diseases it is important to have an understanding of the heart, its anatomy, the circulation of blood through the heart's four chambers and the electrical system that keeps our hearts in rhythm.

Click on the image at right for a guided tour of the heart and how it works. You can learn about:

• What happens when the heart beats
• How the blood flows through the heart
• How the valves work
• What the heart's natural pacemaker is and what it does