A visual guide to your heart
In The Heart Explained, we describe what our hearts do and how they function, and we discuss the symptoms, causes, and treatment options for more than 20 common heart diseases.
This program showcases dozens of easy-to-understand animations with clear descriptive text to explain how our hearts work when they’re healthy and what’s happening when they’re not.
Every day, a normal heart beats an average of 100,000 times. That translates into about 2.5 billion heartbeats in a typical lifetime.
And yet we rarely think about all the work our hearts are doing until something goes wrong. When it does, understanding what’s going on can be key to recovery.
The Heart Explained will help you take control of your heart health.
What’s on this site?
Your heart: The basics
Here, we show you how your heart is constructed, where it is in your chest, how it pumps blood, what happens when it beats, how its electrical system works, and how blood circulates around your body.
Arrhythmias
If your heart is beating too quickly, too slowly, or irregularly, you may have an arrhythmia. In this section, we talk about the most common ones: atrial fibrillation, atrial flutter, supraventricular tachycardia, ventricular tachycardia, sinus bradycardia, and bradycardia caused by atrioventricular block.
Bundle branch blocks
The electrical signals that control your heartbeat can sometimes be blocked or interrupted, causing a disorder called heart block. Three common types of heart block are left bundle branch block, right bundle branch block, and atrioventricular block. Because atrioventricular block causes your heart to beat abnormally slowly it is usually classed as an arrhythmia, and we discuss it in our Arrhythmias section.
Heart failure
Heart failure develops when your heart is unable to pump as effectively as it should, often because of age- and lifestyle-related disorders like coronary artery disease. Heart failure is classified as left heart failure or right heart failure. If both sides of your heart are affected, you have biventricular heart failure.
Heart valve disorders
The heart’s valves ensure that blood flows through your heart in the right direction. Disorders like aortic valve stenosis, aortic valve regurgitation, mitral valve stenosis, mitral valve regurgitation, mitral valve prolapse, and tricuspid valve regurgitation all interfere with blood flow, either because of leaking or because of valve narrowing.
Arteries & circulation
Disorders like hypertension (high blood pressure) and atherosclerosis (clogged and narrowed arteries), can increase your risk of having a heart attack. Atherosclerosis of the coronary arteries can also cause angina (chest pain), as can disorders that cause the heart’s blood vessels to constrict or spasm.