Hypertension - High Blood Pressure Known as the 'silent Killer’ Rarely Has Obvious Symptoms

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CHAPTER- I

As the arteries grow hard, the heart grows soft.

(Willium benkinson)

1.1 INTRODUCTION:

High blood pressure Known as the 'silent killer’ rarely has obvious symptoms.

Ponnarasi, P, (2016), stated that life is not merely to be alive, but to be healthy and wealthy. Every day we hear about new diseases and get fear and panicked. Despite incredible improvement in health since 1950, there are still a number of challenges, and cardiovascular disease remains among the leading causes of death worldwide. Hypertension is a very common condition under cardiovascular disease.

Benjamin Mc Donald, (2007), depicted that cardiovascular system means the system of heart and blood vessels of human body. The main organ of the circulatory system is the heart, which is responsible for pumping oxygenated blood throughout the body. Without the heart, a human cannot live. The heart is a muscle made up of four chambers separated by valves and divided into two halves. The general term used to cover malfunctions of the heart is Heart Disease, or sometimes Cardiac Disease ("Cardiac" is a Latin term for the heart).

Ross & Wilson, (2014), stated that the cardiovascular system ensures a continuous flow of blood to all body cells, and its function is subject to continual physiological adjustments to maintain an adequate blood supply. Blood pressure is the force or pressure that the blood exerts on the walls of blood vessels. Keeping blood pressure within normal limits is very important. If it becomes too high, blood vessels can be damaged, causing clots or bleeding from sites of blood vessel rupture. If it falls too low, then blood flow through tissue beds may be inadequate. This is particularly dangerous for essential organs such as the heart, brain or kidneys.

Phipps, (2006), stated that Hypertension is defined as persistent elevation of systolic blood pressure (SBP) at a level of 140 mm hg or higher & diastolic blood pressure (DBP) at a level of 90 mm hg or higher.  The higher the blood pressure greater the risk for heart attack, heart failure, stroke, & kidney disease. The incidence of hypertension according to joint national committee on prevention, detection, evaluation & treatment (JNC VII) more than half of the individuals from 60-69 years of age & 3/4th of those 70 & older are affected by hypertension.

         Park. K, (2012), depicted that the prevalence of hypertension was 59.9 & 69.9 per 1000 in males & females respectively in urban population, 35.5 & 35.9 per 1000 in males & females respectively in the rural population of India. High blood pressure is a major risk factor for mortality; the high mortality is due to complications of high blood pressure that is stroke, congestive cardiac failure, heart attack, & kidney failure. The higher the pressure greater the risk & lower the expectancy of life.  In India death from hypertension is mainly from stroke and heart disease.

Merai R, (2016), concluded that about 1 of 3 U.S. adultsor about 75 million people have high blood pressure. Only about half (54%) of these people have their high blood pressure under control. This common condition increases the risk for heart disease and stroke, 2 of the leading causes of death for Americans. High blood pressure is called the “silent killer” because it often has no warning signs or symptoms, and many people do not know they have it. That’s why it is important to monitor blood pressure regularly.

Joyce M. Black, Jane Hokanson Hawks, (2002), stated that the heart requires a balance between oxygen supply and demand in order to function properly. The integrity of the coronary artery is an important determinant of oxygen supply to the heart muscles. Any disorder that reduces the size of lumen of coronary arteries may cause a decrease in blood flow and oxygen  delivery to the myocardium which is life threatening condition characterized by the formation of local necrotic areas within the myocardium. Acute Myocardial Infarction usually follows the sudden occlusion of a coronary artery and the abrupt cessation of blood and oxygen flow to the heart muscles, leads to development of necrotic areas which can be lethal.

Brunner and Siddhartha’s, (2005), depicted that atherosclerotic plaque and subsequent thrombus formations are the most common causes. It is identified that nearly 95 per cent of the people who developed a fatal cardiovascular diseases had at least one of these major risk factors: high blood pressure, smoking, diabetes beside a poor diet and overweight.

Midha T, (2016), revealed that hypertension is the most common form of heart disease and also a major risk factor for other heart disease like coronary heart disease (CHD). A recent meta-analysis has shown prevalence of hypertension as 40.8% and 17.9% in urban and rural population of India respectively.

Coronary artery disease is a condition in which the blood supply to the heart muscle is partially or completely blocked. This is due to the buildup of cholesterol and other material, called plaque, on their inner walls. This buildup is called atherosclerosis. CAD, is also called Coronary arteriosclerosis, Coronary atherosclerosis. Coronary artery disease (CAD) is the most common type of heart disease. The heart muscle needs a constant supply of oxygen-rich blood. The coronary arteries, which branch off the aorta just after it leaves the heart, deliver this blood. Coronary artery disease can block blood flow, causing chest pain (angina) or a heart attack (also called myocardial infarction). (http://heart.bmj.com/content/91/6/719&Medlineplus.com)

Coronary artery disease (CAD) continues to be a major causeof morbidity and mortality in Western societies. Approximately two out of every three incidents of myocardial infarction (MI) occur without warning and of note, one third of first MIs arefatal; 20% of patients die out of hospital and 13% die withinthe first 24 to 48 hours of hospitalization.   (http://www.merckmanuals.com/home/sec03/ch020/ch020b.html#sec03-ch020 -ch020b)

Reddy SS, Prabhu GR., (2005), depicted that Indians have the highest rates of CAD all over the world. It is 2-4 times higher at all ages and 5-10 times higher in those below 40 years of age. The excess burden of CAD in Indians is due to combination of nature and nuture. Due to industrialization and changing feature of socio-economic scenario, the incidences of CAD are rising in the developing countries as well prevalence of CAD in India is 3 to 4 fold higher than in America and Europe.