So just what is "heart disease"? Actually, "heart disease" is a big umbrella term that covers a lot of diseases. To make it easier to understand, let's start with some definitions. We will get very basic here, because not everyone has a degree in a medical field, and health class was a long time ago.
Arteries - the blood vessels that carry oxygen-rich blood away from the heart to all the cells in your body. Your cells depend on the oxygen carried by this blood to function.
Veins - the blood vessels that carry blood back to the heart from all the parts of your body.
The heart pumps oxygen-rich blood out through the arteries, and it travels throughout every part of your body, delivering oxygen and nutrients to the cells. The cells take the oxygen and nutrients and exchange waste products like carbon dioxide. The blood then enters the veins to travel back to the heart. Once it reaches the heart, the blood is re-oxygenated by the lungs and the cycle starts over.
As you can imagine, the heart has an easier time pumping all this blood around if the arteries and veins are clear and free of blockages.
However, blockages do occur in the form of plaque and clots.
What is Plaque?
Plaque is a material made up of fatty substances, cholesterol, cellular waste, calcium, and fibrin (a material in blood that helps it to clot). Plaque builds up inside the artery walls. Recall that arteries are the vessels that take oxygen from the heart to the rest of your body. When plaque builds up, it's kind of like sludge building up inside a plumbing pipe that slows down and could eventually stop the flow. This narrowing of the arteries can keep vital oxygen from reaching the parts of the body downstream from the narrowing or blockage.
What is Atherosclerosis?
Atherosclerosis is the term for this build up of plaque in the artery walls. Plaque begins building up in the arteries as early as childhood. Scientists don't know exactly what causes atherosclerosis, but they do know what makes it worse:
- High levels of bad cholesterol (LDL) and triglycerides in the bloodstream
- High blood pressure
- Cigarette smoking
If plaque breaks off or a blood clot forms at the area of a plaque, a complete blockage can occur in the artery. Cells downstream that can't receive the oxygenated blood begin to die.
What is Arteriosclerosis?
Arteriosclerosis is sometimes called "hardening of the arteries." Healthy arteries should be flexible and elastic, but as we age, they become stiff and inflexible. Some arteriosclerosis is expected with aging, but build up of plaque makes it worse.
Now let's break down the umbrella term of "heart disease" into smaller categories. To begin with, let's think in terms of three parts of the body: The heart itself, the blood vessels in the rest of the body, and the brain.
What is Coronary Artery Disease (CAD)?
Coronary Artery Disease (CAD) is the build up of plaque in the arteries in the heart that supply oxygen to the heart muscle itself. Over time, the arteries become narrow and hardened, and the heart muscle gets less oxygen.
What Is Angina?
Angina is a condition in which the heart muscle is not getting enough oxygen because of narrowed, hardened coronary arteries, causing pain and discomfort in the chest. Other symptoms can include pain in the jaw, shoulders, arms, neck, or back. Angina may feel like pressure, or even indigestion. Symptoms in women can differ from those in men (and from the classic symptoms you might think of when you think of heart pain), especially in being more vague and less focused to a specific area.
Over time, the lack of adequate oxygen can damage the heart, leading to more problems.
What Is a Heart Attack?
Heart attack occurs when an artery in the heart becomes completely blocked by plaque or a blood clot. The heart muscle that is supplied by that artery is starved of oxygen and nutrients and begins to die if blood flow is not quickly restored. This emergency condition can lead to death or serious disability.
What Is Heart Failure?
Heart failure is not the same thing as a heart attack. Over time, a combination of high blood pressure and hardening of the arteries causes the heart muscle to have to work harder and harder. As a result, the muscle can become larger, stiffer, and less efficient at pumping blood through the body. A healthy heart would be like a beach ball with a valve in it. If you squeezed the beach ball, you could easily squeeze the water out. But in heart failure, imagine the heart is now more like a basketball filled with water. You could still squeeze the water out, but you would have to squeeze really hard.
This condition is often also called "congestive heart failure." Because blood is being inefficiently pumped through the body, the kidneys try to compensate by retaining fluid in the body. This extra fluid leads to congestion in the lungs (pulmonary edema) and difficulty breathing, and swelling in other parts of the body, especially the legs, feet, and abdomen.
Now, let's talk about the blood vessels.
The Blood Vessels
When plaque builds up in arteries in the limbs, especially the legs and feet, blood flow is diminished. This condition is called Peripheral Arterial Disease (PAD). People with PAD may experience cramping pains during exercises such as walking because the muscles in the legs aren't getting the oxygen they need. Continued poor blood flow can lead to poor wound healing and gangrene, and it not corrected, amputation.
In the Brain
What does the brain have to do with heart disease? Well, I'm glad you asked!
Just like the arteries around the heart and in the limbs, the arteries supplying the brain can be narrowed or blocked by arteriosclerosis and plaques and blood clots.
When a blood vessel supplying the brain becomes blocked, the brain is starved of oxygen and experiences an ischemic stroke. Just as in the heart, when the brain cells are deprived of oxygen and nutrients, they begin to die, and permanent damage can occur if circulation is not quickly restored.
You may have also heard of a "mini-stroke" or transient ischemic attack or TIA. This condition is also caused by blocked blood vessels, but the symptoms usually last a very short period of time, without permanent impairment. However, they are a risk factor for future ischemic strokes.
High blood pressure over time can also damage and weaken these arteries. If a weakened artery bursts, a hemorrhagic stroke occurs.
Either type of stroke is a medical emergency and can lead to death or disability.
Now that you know the definitions of the major conditions under the "heart disease" umbrella, in the next few articles, we will learn the signs and symptoms for each one.
Thanks for reading this far, and be sure to share this Love Your Heart series with someone you love!