What are Preventive measures of Myocardial Infarction its risk factors and management?
Myocardial infarction is a major killer of well settled class of people and intellectuals in India when they are at the prime of their carrier and life. The rising incidence, is due to sudden change in the status of life. the increasing graph can be prevented by proper health education. The main principle of prevention of ischemia/infarction is, to minimise the work load of heart and enhance the supply of pure (oxygenated) blood by removing risk factors resulting Heart Attack.
Preventive measures of Myocardial Infarction or Heart Attack
Myocardial infarction is a major killer of well settled class of people and intellectuals in India when they are at the prime of their carrier and life. The rising incidence is due to sudden change in the status of life. The increasing graph can be prevented by proper health education. The cause of myocardial infarction or acute chest pain is due to lack of oxygenated blood supply, both during normal condition and during stress & strain. This is due to narrowing of coronary arteries or due to sudden blockage.
The main principle of prevention of ischemia and infarction is, to minimise the work load of heart and enhance the supply of oxygenated blood by removing risk factors which cause the narrowing or blockage of the coronary arteries resulting Heart
Attack.Risk factors of Heart attack :
Risk factors of myocardial infarction are divided into two groups:
(1)Major risk factors
(2) Relative risk factors
(1) Major risk factors are:
(i)Smoking
(ii)High cholesterol (Lipid profile)
(iii)Hypertension
(iv)Anxiety (stress)
(2)Relative risk factors are:
(i)Obesity and overweight
(ii)Lack of physical exercise
(iii)Hereditary (Family h/o Diabetes mellitus, Hypertension, High cholesterol, Coronary artery disease)
(iv)Uncontrolled diabetes mellitus
(v)Use of oral contraceptivesMajor risk factors :
It has been observed that smoking, hyper-lipidaemia and high blood pressure form a triangle of highest risk factors which make a middle aged person more susceptible to coronary artery disease. Anxiety precipitates myocardial infarction much faster as it acts like catalyst to any of the three high risk factors.
(i) Smoking :
Smoking is one of the major risk factors of heart attack. In India about 40% of deaths following heart attack are due to smoking and the incidence is higher in young smokers. Tobacco smoke contains roughly hundred different types of chemicals, most of them are harmful but the maximum harm is done by nicotine & tar. Nicotine affects the heart blood vessels and nervous system while tar & its by-products cause carcinoma.
Nicotine causes vasoconstriction due to arterial muscle spasm; hence there is a rise in blood pressure. This vasoconstriction leads to decrease in supply of blood to the heart and other organs. There is rise in pulse rate (Tachycardia) and in course of time leads to ischemia (Angina/ Infarction). In addition to this there are other lung related diseases like Chronic Bronchitis.Bronchiactesis and Emphysema etc. decreases the function of lung and finally leads to Congestive Cardiac Failure and Left Ventricular Failure in addition to coronary artery disease.
Carbon monoxide which has more affinity for haemoglobin compared to oxygen fixes to haemoglobin causing fall in circulating blood oxygen.
Other tar substances damage the arterial lining, this leads to clinging of cholesterol to blood vessels more so to coronary arteries.
Rule of Thumb :
• Smoking increases risk of Heart Attack by 50%. It is directly related to number of cigarettes you smoke and how long you have smoked.
• Smoking reduces man's life span by 5 to 10 years.
• If you leave smoking today the incidence of heart attack drops by 50% in one year's time and comes close to normal incidence after 5 to 10 years.
(ii)Blood Cholesterol :
Cholesterol is a very essential product of fat metabolism of human body cells. It is an essential component for cell membrane function, synthesis of myelin sheath and steroid hormones. Once the serum cholesterol rises beyond normal levels, it becomes harmful and accentuates atherosclerotic changes. Coronary arteries are more sensitive to this rise.
Lipid Metabolism :
Cholesterol and other fatty substances are carried around the body by substances called Lipo Proteins. Two of these Lipo Proteins, Low Density Lipo Protein (LDL) and High Density Lipo Protein (HDL) play an important role in the process of atherosclerosis. Higher concentration of Low Density Lipo Protein (LDL) enhances atherosclerosis.
The increased content of LDL in the intima of blood vessel is acted upon by oxygen free radicals to form oxidised LDL which can cause injury to endothelial lining of the blood vessels. A chemo tactic factor present in the oxidised LDL recruit circulating monocytes, which enter into sub-endothelial to become tissue Macrophage. Oxidised LDL inhibits the mobility of Resident Macrophage and as a consequence resident Macrophage takes up oxidised LDL to become "Foam Cell". They along with the endothelial injury initiate the formation of Fatty Streak (Atherosclerosis).This fatty streak is characterised by accumulation of cells loaded with cholesterol esters.
With the increasing levels of oxidised LDL there is increasing adherence of circulating monocytes to arterial endothelium, followed by penetration into endothelial space. Cyto-toxicity of oxidised LDL leads to further loss of endothelium and platelets settle over broken endothelium. They secrete a substance known as platelet derived growth factor which moves to act the multiplication of cells present deep in the arterial wall or exposed muscle cells. This leads to development & progress of atherosclerosis.
The High Density Lipo Protein (HDL), remove fatty deposits from the cells in the arterial wall before deposition consolidates into an atherosclerotic change & deposit. It also helps in transportation of LDL from tissue to liver, where it is broken down. The Aim is to keep HDL high and LDL low.
Total Cholesterol Level :
• Less than 200 mg/dl is Best
• 200 to 239 mg/dl is Borderline High
• 240 mg/dl or more means you're at increased risk for Heart Attack
LDL cholesterol levels :
• Below 100 mg/dl is ideal for people who have a high risk of heart disease
• 100 to 129 mg/dl is near optimal
• 130 to 159 mg/dl is borderline high
• 160 mg/dl or above means you're at higher risk for heart disease
HDL cholesterol levels :
• Less than 40 mg/dl means you're at higher risk for heart disease
• 60 mg/dl or more greatly reduces your risk of heart disease
Triglyceride :
Less than 150 mg/dl is best
To label a patient suffering from high cholesterol at least 2 to 3 samples of cholesterol level should be undertaken in a period of 3 to 4 months after dietary control.
How to control cholesterol:
Lipids are exogenous (dietary) or endogenous (metabolic) in origin. Main dietary (exogenous) lipids are cholesterol and triglycerides. These are fat soluble and after absorption from intestine it becomes water soluble for transportation in blood stream. They are linked to apo-protiens to form a lipoprotein called chylomicron. They enter into the blood stream through thoracic duct. In blood stream chylomicron is hydrolysed by lipoprotein lipase releasing triglycerides which are broken in to free fatty acids. Cholesterol rich in chlomicron are taken up by liver cells and are used for synthesis of very low density lipoprotein (VLDL) and LDL.
Hyper-lipidaemia : is of three types
(a) Polygenic, multiple gene and environmental induced. About 2/3rd cases belong to this group (with sedentary life, diet, alcohol, smoking, obesity etc.
(b) Secondary hyperlpidaemia, secondary to Diabetes mellitus, Chr. Liver failure, obstructive jaundice, Chr. alcoholics, hypothyroidism & nephritic syndrome.
Drugs like Beta blockers, Oestrogen, Corticosteroids etc. and pregnancy
(c) Familial single gene defect has complete lack of LDL in the body. It occurs in
1 out of 500 births.
Dietary Advice :
Consume following food items
• Food with high fibre content like fresh fruit, green vegetables, salad etc. and food not over cooked.
• Coarse grain like whole wheat flour, gram, soyabeans,corn, peas, lentils brown bread etc.
• Use skimmed milk and its products like curd, butter milk, and cottage cheese.
• Non vegetarians can eat white meat like chicken and fish.
• Use unsaturated fat for cooking purpose like corn oil, Soya bean oil, sun flower oil, as they have low cholesterol contents.
• Garlic and Onion are natural ingredients which help in regulating cholesterol.
Avoid following food items :
• Processed fruits and vegetables, over cooked or deep fried foods, jam and jellies etc.
• White bread, cookies, pastries, fast foods, Puris, deep fried vegetables, pulses with ghee or butter.
• Avoid red meat, eggs especially yolk, kidney, brain etc.
• Do not use saturated fats like pure ghee, butter, mustard oil, coconut oil and vanaspati as they have harmful ingredients of cholesterol.
If with dietary control cholesterol does not come down below 250 mg/dl, medical treatment with drugs is indicated.
Gist:
All food of animal origin are rich in cholesterol while all foods of plant origin are poor in cholesterol. Diet, smoking, alcohol etc are the key factors in preventing atherosclerotic changes & reducing the risk of coronary heart disease.
(iii)Hypertension:
Normal blood pressure ranges 120/80 mm of Hg (+_) 10 in young adults. Regulation of blood flow & its pressure is done by carrying vessels called arterioles. If arterioles become narrow for some region, the flow of blood is hampered & BP rises. This may lead to over work by the heart and if this rise of pressure continues leads to high BP.
Hypertension is of two types:
1. Primary: Cause is not known.
2. Secondary: This is secondary to
• Renal diseases
• Diabetes mellitus
• Coarctation of aorta
• Toxaemia of Pregnancy
Secondary hypertension can be controlled by removing the cause. Obesity, smoking and anxiety are main risk factors of hypertension which can be controlled by removing the cause & by medication, keeping your patient protected from myocardial infarction/ ischemia.
(iv)Anxiety or Stress:
In today's modern fast competitive life, some anxiety & stress is essential for growth and progress of an individual. Stress makes an individual prone to heart attack or angina. Anxiety /stress can be minimising by relaxation through yoga, meditation, adequate rest 7-8 hours sleep and by adjustment with diet & situation. (2) Relative risk factors :
(i)Overweight and obesity leads to hyper-lipidaemia and in course of time hypertension. Use of low calorie food with more roughage and regular exercises are beneficial to regulate overweight & obesity.
(ii)Lack of physical exercises :
Regular exercises like walking, running, cycling, carrying light weight etc are beneficial to prevent overweight, control blood cholesterol and tone up your muscles.
(iii)Uncontrolled diabetes : Heart attacks are more common with patients having uncontrolled diabetes mellitus. Diabetes also precipitate early ischemia/infarction if the person is smoker, or suffering from hypertension and or high lipid level.
(iv)Heredity and contributory factor : IT is well known, that the incidence of myocardial infarction/ischemia in certain family is much higher involving young age members. This is due to some genetic factor. We cannot change genetic factor but can pay our attention to other risk factors and avoid heart attack.
(v)Oral contraceptives : In some female patients oral pills cause hypertension and rise in blood cholesterol levels. This can be discontinued and other form of birth control measures may be used.