The heart is divided into four chambers, or rooms: the left atrium, the right atrium, the left ventricle, and the right ventricle. Each chamber is sealed by a valve, so that blood can go one way but not the other.
When you listen to a heartbeat, you can hear that the beat happens in two parts: lub-dub. The first part of the beat pushes the blood from the atria (the small chambers on the top of the heart) to the ventricles (the larger ones on the bottom), and the second part of the beat pushes the blood out of the heart.
Every single cell in our bodies requires oxygen to produce energy from food. It is the one essential ingredient; we cannot survive for any extended period of time without oxygen. This is why the heart is so important. Its primary job is to circulate oxygen-rich blood throughout our entire body.
The two sides of the heart perform two different functions toward this end. The right side of the heart collects oxygen-poor blood and sends it to the lungs to be replenished with oxygen and to rid itself of carbon dioxide.
The left side takes the oxygen-rich blood coming from the lungs and recirculates it through the body to your muscles and organs. Oxygenated (oxygen-rich) blood is carried by the arteries away from the heart, and oxygen-depleted blood is carried by the veins back to the heart.
Coronary heart disease is the leading cause of death in the United States. It can be caused by many different factors, including congenital heart defects, heart valve infections, and heartbeat irregularities., which is the most common form of heart disease, affecting 7 million Americans today
What is coronary artery disease?
Like all the cells and muscles in the body, the heart muscle itself needs oxygen. And as with the rest of the body, that life-sustaining oxygen is carried to the individual cells of the heart by arteries. These are called the coronary arteries. There are three main coronary arteries: one on the left that splits into the left anterior descending, or LAD, and the circumflex, and one on the right, the right coronary artery, or RCA.
If the coronary arteries are blocked and unable to do their jobs, then the heart is left without oxygen and unable to do its job. Depriving the heart of oxygen for even a brief period of time will result in the death of some of the heart muscle-otherwise known as a heart attack.
The heart requires more oxygen when it’s working hard, which is to say, when you’re working hard. That’s why many people with coronary artery disease classically experience chest pains when they’re exerting themselves-jogging for instance, playing tennis, or even simply taking out the garbage. Your heart may be able to sustain itself at rest, but when you’re exerting yourself, it needs more oxygen.
The limited amount of oxygenated blood that reaches the cells through the diseased and partially blocked arteries simply isn’t enough. These classic chest pains, also known as angina, are the diseased heart’s signal that the coronary arteries aren’t allowing enough oxygenated blood to reach the heart muscle.
When the amount of blood to a muscle is insufficient, that low-oxygen state is called ischemia. Coronary artery disease is often also called ischemic heart disease (IHD) as a result. A heart attack occurs when the coronary arteries are sufficiently blocked as to rob the heart muscle (the myocardium) of oxygen for long enough that part of the tissue dies (a condition called infarction).
For this reason, a heart attack is called a myocardial infarction, or MI. Peripheral artery disease, or PAD, is when blockages occur in arteries other than the coronary arteries. These are no less serious: A stroke occurs when oxygen flow to the brain is blocked, and when oxygen flow to the limbs is blocked, the outcome can be gangrene.