A Beginners Guide To Heart Disease

The cardiovascular system is a key component in the life of a human being. Our bodies are made up of trillions of tiny cells, each demanding oxygen, water, and nutrients.

Located deep inside our bodies it’s impossible for these cells to find enough of these life requirements to continue thriving. The cardiovascular system is the solution to this problem. It delivers the water, oxygen, and nutrients needed for the cells to continue growing despite never actually coming in contact with the environment around us. 

The heart pumps oxygenated and nutritious blood throughout the body, into tiny capillaries feeding our every cell. The human body has an incredible 100 000 km (60 000 miles) of circulation tubing running throughout the entire body. 80% of this length is made of from the capillaries.

A Beginners guide to heart disease

What is Heart Disease?

Heart disease is currently the leading cause of death in The United States and Australia, and is the second leading cause of death in Canada [4-6]. It is a process that often takes years to develop, and comes in many different forms.

Heart disease (also known as cardiovascular disease or CVD) generally stems from poor dietary, and exercise habits. These build over time, and result in damage to the blood vessels of the body. High blood pressure, obesity, atherosclerosis, chronic inflammation, and diabetes are all major risk factors for cardiovascular disease. 

Although the process leading up to cardiovascular disease is not well understood (and highly debated), the main theory is that cholesterol is the executive contributor to heart disease. 

 

Common Forms of Heart Disease

Heart disease comes in many colors. There is not just one type. This may come to a surprise because heart disease is generally treated as if it is just one thing. In fact is is many different disorders. 

Heart disease can include blockages forming in the arteries feeding the heart (myocardial infarction or heart attack), high pressures within the arteries, or issues with the atria of the heart leading to an inability for the heart to pump the blood effectively. There are all kinds of different scenarios that fit what we refer today simply as heart disease. 

 

The most common heart conditions include:

  • Coronary artery Disease
  • Congestive Heart Failure
  • Arrhythmia
  • Angina
  • Hypertension (High blood pressure)

 

Contributing Factors of Heart Disease

There are many different factors that can contribute to heart disease including:

  • Diabetes
  • High cortisol levels (stress)
  • Age (over 45)
  • Sex (men)
  • Smoking (major risk factor)
  • Diet (high sugar and processed foods)
  • Obesity 
  • Physical activity level
  • Viral or bacterial infections

Atherosclerosis

Atherosclerosis is a condition where the blood vessels throughout the body begin to harden and narrow. Eventually they narrow enough to occlude blood flow enough to cause the tissues it feeds to starve for oxygen. 

Our blood vessels are made up of multiple layers of specialised cells. The middle layer is the muscle that tense and relaxes to control blood pressure, and the innermost layer is a special tissue known as epithelial tissue This same tissue can be found throughout the entire digestive tract. They worl to keep the inside of the blood vessels toned, and smooth, which allows the blood cells to flow with as little resistance as possible. It is this layer that is most affected by atherosclerosis. When cholesterol is deposited on the walls of the arteries in this epithelial tissue, it will begin to form a cholesterol plug. Over many years this will continue to build up, eventually oxidising, and hardening. If allowed to continue, this will eventually block the artery comopletely. 

During a heart attack, atherosclerosis has lead to a blockage in the coronary arteries feeding the heart. This causes the heart tissue to die, which in many cases is fatal. If the heart dies, you die. 
Athersclerosis is a long term, chronic condition. It builds over many years to the point of eventual blockage. Some reports suggest people as low as 16 show signs of atherosclerosis forming which will become much more evident over the next 20-30 years. 

This condition is the main cause for strokes, heart attacks, and peripheral vascular disease. There are actually 2 main ways this can happen. The cholesterol plaquing can actually build up enough to occlude the artery completely, which is fairly common in heart attacks. The other way, is for a cholesterol “plug” to rupture and detach from the wall of the artery. It will then travel through the blood stream, eventually lodging itself in another narrowed section, or a smaller artery. This is a common cause of strokes.

Risk factors for atherosclerosis:

  • High levels of homocysteine (can be caused by low B vitamin intake)
  • Obesity leading to high levels of C-Reactive protein
  • Oxidative stress (from smoking or environmental factors)
  • Genetic 
Atherosclerosis diagram

 

Angina

Angina happens when oxygen and blood supply is cut off momentarily or partially in the arteries feeding the heart. It causes temporary pain in the chest. This usually comes on during exercise and goes away after some rest. 

Angina is not fatal, but is a good indication of an impending cardiovascular event. It is associated with a narrowing of the arteries, which upon excercise or other exertion, the oxygen demands of the heart cannot be met by he rate of blood flow feeding the arteries. 

 

Coronary Artery Disease

The heart has a very high demand for oxygen and nutrients. Even though it is the organ that pumps the blood around the body, the inside of the heart does not absorb much of this oxygen and nutrients. This part of the heart is strictly designed for moving blood efficiently. Therefore, the cells of the heart will need a rich supply of blood via specialised arteries. This is the coronary arteries. 

The coronary arteries wrap around the heart, and feed the cells via capillaries. If something were to happen to these arteries, such as a blockage or plaquing, sections of the heart may lose access to its oxygen and nutrients. If this happens, the cells will stop working properly right away, and will soon die if blood flow is not restored. This is seen as a heart attack. 

If the blockage occurs in an artery that feeds the electrical nodes of the heart, which are responsible for initiating the heartbeat, this node can die. Once the node is dead, the heart is forced to beat via its backup system, which is not nearly as effective. These people may not recover, and those who do will have long term disabilities due to a weak heart.


Congestive Heart Failure

Congestive heart failure is the result of a heart attack. When the heart tissue is damaged, the heart won’t function the way it normally should. In congestive heart disease, blood is not able to move around the body effectively. Generally, there will be a specific portion of the heart that is affected since heart attacks are caused by an occlusion of an artery that feeds a specific portion. If the entire heart was effective, death is unavoidable. 

If the damage is present in the right side, the blood will begin to build up in the extremities. This is because the right side pumps blood into the pulmonary arteries to oxygenate the blood. If the right side is weak, blood will begin to back up behind it while the left heart pumps more blood. If the left side is affected, the blood will begin to build up in the pulmonary arteries and causes fluid to accumulate in the lungs. Both are bad scenarios and will require extra care for the duration of life, which will also become highly reduced. 

Congestive heart failure diagram


Arrhythmia

The term arrythmia represents a wide range of electrical discrepancies in the heart. This can come in a wide range of types, and not all are a problem. 

The heart is controlled by a set of nodes that are on a timed control to fire the heart. They originate an electrical impulse, which starts a chain reaction in the heart tissue, causing it to contract and pump the blood through the body. When there is a problem with this system, the heart beat may not be sinced, or beats may be missed. 

Arrythmias are easily diagosed with the use of an ECG. Depending on the type, and the cause treeatment may not be necessary. 

Types of Arrythmias:

  • Atrial fibrillation (upper chambers not firing properly)
  • Bradycardia (slow heart rate)
  • Tachycardia (fast heart rate)
  • Premature contraction
  • Ventrillation fibrillation (uncontrolled contractions of the lower chambers)
  • Conduction disorders
Arrythmia diagram

 

Essential Hypertension

In most cases of hypertension (high blood pressure), there are no known causes. For these cases where the doctor can’t determine what is causing the high blood pressure, “essential hypertension” is used. If the cause is known it’s called secondary hypertension. 

If you can find out the cause of the hypertension, treatment can be much more specific. Usually the treatment is the same, but tailoring it towards the cause of the high blood pressure will be much more effective. 

For severe high blood pressure (170/110), synthetic treatments are advised as this is a medical emergency. 

Nearly half of all untreated high blood pressure cases result in organ damage after a period of 7-10 years.

 

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