The circulatory system consists of the heart and all the blood vessels including the veins, arteries and capillaries. The heart contains a natural pacemaker, known as the sinus node, which produces electrical impulses that trigger it to contract. As the heart contracts, blood flows through the four chambers: the right and left atrium on top, and the right and left ventricles on bottom. There are many different diseases of the heart and circulatory system, which can interfere with the normal flow of blood.
Pericarditis
The pericardium is the thin membrane that surrounds the heart. This membrane consists of two layers that contain a small amount of fluid in the middle. Pericarditis is a condition that occurs when the pericardium becomes inflamed due to infection or injury to the heart. As the membranes swell, fluid builds-up within the pericardium, which constricts the heart and inhibits the normal functioning.
Endocarditis
Endocarditis is an infection of the lining of the heart, but also often affects the heart valves and muscle. This disease of the heart occurs when bacteria travel through the bloodstream and lodge onto heart valves, most commonly artificial valves or valves that are damaged.
Endocarditis may be acute, meaning the onset is sudden, or subacute, which develops over a period of several weeks to several months. Acute endocarditis causes a sudden high fever, fast heart rate and fatigue and can become life-threatening very quickly as it causes damage to the heart valves, according to the Merck Manual. Subacute endocarditis causes mild fever, fatigue, moderately fast heart rate, weight loss, sweating and anemia (low red blood cell count).
Coronary Artery Disease
Coronary artery disease (CAD), also called coronary heart disease, is the narrowing of the coronary arteries, which are the arteries that supply the heart with oxygen-rich blood. CAD is caused by atherosclerosis, which is the build-up of plaque, a substance that consists of cholesterol, fat, calcium and minerals.
When blood flow and, therefore, oxygen is restricted to the heart, chest pain and discomfort, known as angina, occurs. If blood flow to an area of the heart is completely blocked, it may cause a heart attack. Over time, the heart may not be able to pump enough blood throughout the body, which results in heart failure as explained by the National Heart Lung and Blood Institute.
Chronic Valvular Disease
The heart consists of four valves that work to control the flow of blood within the heart by opening and closing during the contractions of the heart. There are several diseases of the valves. Aortic incompetency is the inability of the aortic valves to close properly, allowing blood to leak back into the left ventricle. Over time, symptoms such as shortness of breath, fatigue, chest pain, fainting and heart palpitations may occur.
Aortic valve stenosis, another valvular disease, occurs when the aortic valve becomes obstructed inhibiting the flow of blood from the left ventricle. The ventricle must then work harder, which over time, can result in dizziness, fatigue, headache and fainting.
The other valves of the heart, including the mitral valve, tricuspid valve and pulmonary valve, can also have similar diseases that can affect the flow of blood within the heart.
