The following points highlight the nineteen major disorders of circulatory system. Some of the disorders are: 1. Hypertension 2. Coronary Artery Disease 3. Arteriosclerosis 4. Heart Block 5. Cerebro Vascular Accident 6. Rheumatic Heart Disease 7. Congenital Heart Diseases 8. Oedema 9. Ebstein’s Disease 10. Fibrillation 11. Tachycardia 12. Bradycardia 13. Cardiac arrest 14. Heart failure 15. Heart attack and Others.
Disorder # 1. Hypertension (High blood pressure):
It is the most common disease affecting the heart and blood vessels. A blood pressure of 120/80 is considered normal. But the increase in blood pressure beyond 140 mm Hg (systolic) and 90 mm Hg (diastolic) is called high blood pressure (hypertension). High blood pressure can harm heart, brain, kidneys and eyes.
Causative factors of Hypertension:
Generally, a diet full of extremely oily and greasy products, is known to increase cholesterol level, causing thickening of the arteries which results in high blood pressure. Tobacco smoking speeds up the heart rate, contracts blood vessels and raises blood pressure. Mental tension also causes hypertension. Kidney disorder may be cause of high BP.
Disorder # 2. Coronary Artery Disease (CAD) or Atherosclerosis or Atheroma:
It refers to the deposition of fatty substances specially cholesterol and triglycerides in the tunica interna and smooth muscles of medium sized and large arteries.
Such a deposition is called atherosclerotic or atheromatous plaque (Fig. 18.26) which deforms the arterial wall. Gradually these plaques grow. As a result, the lumen of the artery decreases and the flow of the blood is reduced. In extreme cases these plaques may block the artery completely.
The smooth muscles proliferate because these plaques provide a rough surface to the platelets which cause release of platelet derived growth factor (PDGF).
If such plaques are formed in the coronary arteries the latter reduce the blood supply to the heart or may stop the blood supply due to complete blockage of the coronary arteries. This may result in heart attack or stroke. High blood plasma concentration of cholesterol in the form of low density lipoproteins (LDL) is responsible for atherosclerosis.
Disorder # 3. Arteriosclerosis:
Hardening and loss of elasticity of the arteries is called arteriosclerosis. In arteriosclerosis, calcium salts precipate with the cholesterol which forms plaques. Ultimately, this calcification of the plaques, makes the walls of the arteries stiff and rigid.
Therefore, arteriosclerosis is referred to as the ‘hardening of the arteries’. These affected arteries lose the property of elasticity and their walls may rupture. The blood which comes out from the ruptured wall may clot and block the path of blood flow. As a result, such a clot formation (thrombosis) in the coronary artery may lead to a heart attack.
Disorder # 4. Heart Block:
It is a condition in which impulses ate interrupted at any point along the conducting system of the heart. Thus impulses do not follow the normal conduction pathway.
Two common types of heart block are found:
(i) AV block:
It occurs at the atrioventricular node. The impulses from the SA node do not reach the AV node.
(ii) Bundle branch block:
It involves one of the branches of the bundle of His.
Disorder # 5. Cerebro Vascular Accident (CVA):
Sometimes it is referred to as a stroke, which is the sudden interruption of blood flow to a portion of the brain because of block or rupture of a cerebral blood vessel. Thus the brain cells do not get oxygen and glucose. This can cause paralysis, loss of speech, etc.
Disorder # 6. Rheumatic Heart Disease (RHD):
The patient may have an acute rheumatic fever, joint pains and infection of throat. Rheumatic fever may cause permanent damage of one or more valves (mitral or aortic semilunar valves), pericarditis and myocarditis.
Its causative factor is Streptococcus bacteria. Coxsackie В virus has been suggested as a conditioning agent. The risk of acute rheumatic fever is greatest where there is bad housing, overcrowding and inadequate conditions of hygiene.
Disorder # 7. Congenital Heart Diseases:
Defects or diseases of the heart from the birth are known as congenital heart diseases and are due to some error in the development of the heart.
It is possible that some of these defects may be due to an infectious disease like rubella (German measles) in the mother or administration of some harmful drugs during first three months of pregnancy. A small number of cases of congenital heart diseases are associated with chromosomal abnormalities.
Disorder # 8. Oedema (Puffiness):
If the lymph capillaries fail to return lymph to the blood, fluid accumulates in the tissues resulting in a local swelling called oedema. Oedema may be caused by obstructions in the lymphatic system, excessive capillary pressure, too little protein in the blood or injuries that cause fluids to accumulate in the tissues.
Disorder # 9. Ebstein’s Disease:
It is a congenital downward displacement of the tricuspid valve into the right ventricle.
Disorder # 10. Fibrillation:
Fibrillation is a condition in which the heart muscle is contracting very rapidly but in an uncoordinated fashion. There are atrial and ventricular fibrillation. Ventricular fibrillation is immediately life threatening unless it can be stopped by defibrillation. A machine called a defibrillator is used to do this.
Disorder # 11. Tachycardia:
The heart beats rapidly.
Disorder # 12. Bradycardia:
The heart beats slowly.
Disorder # 13. Cardiac Arrest:
When the heart stops beating, it is called cardiac arrest.
Disorder # 14. Heart Failure:
It is the state of heart when it does not pump blood effectively enough to meet the need of the body. It is sometimes called congestive heart failure because congestion of lungs is one of the main symptoms of this disease. Heart failure is not the same as cardiac arrest (when the heart stops beating) or a heart attack (when the heart muscle is suddenly damaged by inadequate blood supply).
Disorder # 15. Heart Attack (Myocardial infarction):
Death of a part of heart muscle following cessation of blood supply to it. It is acute heart attack. The heart muscle is suddenly damaged by inadequate blood supply.
Disorder # 16. Coronary Thrombosis:
Formation of clot in the coronary artery is called coronary thrombosis. It occurs most frequently in the left anterior descending coronary artery (Fig. 18.27).
Disorder # 17. Stokes-Adams Syndrome:
Altered state of consciousness caused by decreased flow of blood to brain.
Disorder # 18. Angina:
It is also called ‘angina pectoris’. The term angina pectoris means chest pain. In this disease enough oxygen does not reach the heart muscles. The patient experiences heart pain usually in front of the chest. It can occur in men and women of any age but it is more common among the middle aged and elderly people.
Disorder # 19. Ischaemia (pronounced— is-keemia):
Inadequate flow of blood to a part of the heart caused by obstruction to its blood supply.