Heart disease, also known as Cardiovascular Disease, refers to a group of diseases that affect the heart. They are diseases of the arteries that supply blood to the heart and it involves narrowing, partial or total blockage of these arteries. Diseases in this group include Coronary Artery Disease (CAD), otherwise known as blood vessel disease; Arrhythmias, also known as irregular heart rhythms; Heart Defects or Congenital Heart Diseases. These are diseases that already existed in an unborn baby; diseases that a child is born with. When the blockage in the arteries becomes total, it leads to what is known as Heart Attack if it involves the coronary arteries of the heart or Stroke in the brain. Angina, a left-sided chest pain, is the first symptom that is usually associated with cardiovascular disease.
Cardiovascular disease can also be referred to as Atherosclerotic Disease because they are caused by fatty deposits on the wall of the blood vessel known as ARTHEROSCLEROSIS.
To understand what atherosclerosis is, we need to do a quick study of the histological structure of the artery.
A cross section of the wall of an artery viewed under the microscope, shows that there are three layers. The first and innermost layer is known as INTIMA. It is the endothelial layer, lined by a single layer of endothelial cells.
The second layer, the MEDIA, is primarily made up of smooth muscles, while the third layer, the ADVENTITIA (the external elastic layer), is made up of connective tissue and provides elasticity and structural support for the artery.
Development of Atherosclerosis
Atherosclerosis starts with an injury to the internal endothelial lining of the artery. The cause of injury could be physical, chemical, mechanical, drugs or viral. By far the commonest cause of injury to the endothelium of the artery is by free radicals. When damaged, the site of injury on the endothelial lining becomes more permeable to such plasma contents as lipoproteins. These are fat-carrying proteins which bind cholesterol for the purpose of transportation within the circulation. There are majorly two kinds of lipoproteins: the low density lipoprotein (LDL), referred to as ‘BAD’ cholesterol when bound to cholesterol and the high density lipoprotein (HDL) called ‘GOOD’ cholesterol. The lipoprotein causes a breakdown in the composition of the matrix to which cholesterol easily gets attached. When this happens, white blood cells known as monocytes and platelets become attracted to the damaged site where they release chemicals that cause smooth muscle cells to migrate into the endothelium and replicate. This combination of lipoproteins, monocytes, platelets and smooth muscles cells, release debris into the intima. This is what causes the buildup of the cholesterol plaque on the artery.
Next, a fibrous cap made up of collagen, elastin and glycosaminoglycan (the ground substance of the matrix that provides structural support for the artery) forms over the endothelial lining. Upon this, fat cells and cholesterol will increasingly accumulate. As this plaque gets bigger with the accumulation of cholesterol, it gradually blocks the lumen of the artery, cutting off blood supply to areas supplied by the affected artery. It takes 90% blockage of an artery to occur before symptoms of atherosclerosis will begin to appear. These symptoms typically depend on sections of the circulation and arteries affected. Progressive blockage of arteries causes insufficiency of blood, oxygen and nutrient supply to such areas as the heart, if coronary vessels are affected or the brain when cerebral vessels are involved. In the heart, it leads to angina, followed by coronary artery disease (CAD), heart attack and stroke in the brain. Peripheral vascular insufficiency gives rise to such symptoms as pain, coldness of the arms and feet, muscle cramps and impotence in males.
Blood clots can form at the site of the plaque. A blood clot which forms as a result of a partial blockage by a plaque can completely occlude the affected artery to cause myocardial infraction in the heart or stroke in the brain. The clot(s) may travel to other sites and completely block other arteries.
Angina is a squeezing and choking pain on the left side of the chest. This pain usually occurs above the position of the heart in the chest and radiates to the left shoulder, left arm or jaw. Angina is caused by an insufficient supply of blood, oxygen and nutrients to the heart due to a gradual increase of a plaque in the coronary artery. Stress and increased physical exertion are conditions that make an increased demand of oxygen and nutrients by the heart. In the presence of partial blockage of a coronary artery, angina can be preceded by these conditions.
Symptoms of Heart Disease
The symptoms of heart disease include;
- Angina (left-sided chest pain)
- Chest discomfort and tightness
- Weakness and coldness in the arms and legs
- Pain and numbness in the legs and feet
- Pain in the jaw, throat, neck and back.
Diagnosis of Heart Disease
Diagnosis of Cardiovascular Disease may be made only when the patient develops Heart Failure, Stroke or Heart Attack.
Prevention of Heart Disease
- Stop smoking
- Manage heart conditions such as hypertension, diabetes and hypercholesterolemia, well.
- Eat healthy diet – eliminate salt, saturated and hydrogenated fats, beef and dairy products, white flour products and fast foods. Eat more of vegetables, fruits, grains, seeds, nuts, legumes and other fiber containing foods.
- Exercise regularly – brisk walking for 30 minutes, 4 to 5 times weekly.
- Maintain a healthy weight.
- Proper management of stress.
- Engage in healthy hygiene practices.
Risk Factors for Heart Disease
- Family history
- Unhealthy diet
- Sedentary lifestyle
- Poor hygiene.