HEART ATTACK (2)

How do I know if I'm having a heart attack?

A person having a heart attack(myocardial infarction) may experience severe central chest pain often described as squeezing or pressure which may radiate to the shoulders, neck or jaw, with or without headache, dizziness, breathlessness, sweating, vomiting or fainting. The pain lasts longer than a few minutes and is not relieved by nitroglycerin (a drug that widens the coronary arteries, prescribed for patients with angina).Unfortunately however, some people,  will not experience any symptoms at all. This is called silent infarction and is more common in diabetics. If not immediately treated, the heart muscle fibers affected will undergo irreversible damage/infarction/death within 4-5 minutes, lose their functionality and be replaced by scar tissue in a few weeks. Depending on the size of the area affected, this damage may lead to heart failure, arrhythmias, heart rupture, cardiac arrest or death.    A heart attack can occur suddenly but many patients have warning signs days or weeks before the actual event. These warning signs may be in form of recurrent chest pain which is precipitated by exertion and relieved by rest, or increasing frequency and severity of chest pain in people who have already been diagnosed with ischemic heart disease. If medical intervention is sought early, the process can be halted or reversed with appropriate therapy.

In what ways may you be increasing your risk for ischemic disease?

Although there are some predisposing factors which are not modifiable or controllable such as male gender, age(˃40) and heredity (family history of IHD), most of the risk factors for IHD are modifiable. Interestingly, modifying these risk factors simply implies adopting a healthy lifestyle i.e. engaging in regular physical exercises, eating a healthy balanced diet low in saturated fat, avoiding smoking and maintaining optimal body weight. Also, screening for hypertension, diabetes and hypercholesterolemia and controlling them if present will significantly reduce the risk of IHD. Thus, you may be increasing your own risk for heart disease by living a physically inactive life, living on junk foods high in saturated fats and carbohydrate, smoking and not having regular medical checkups.

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Back to Heart attack 1

HEART ATTACK (1)

Myocardial infarction also known as heart attack is an irreversible damage (death) to the heart muscles due to loss of blood supply following narrowing and occlusion of a coronary artery. The coronary arteries are the arteries which supply the heart muscles (myocardium). The right and left main coronary arteries are the first branches of the aorta, carrying oxygenated blood from the left ventricle. These 2 arteries divide into many branches which supply every part of the heart. Unlike many other parts of the body, the heart does not have an alternate source of oxygenated blood. This is why the coronary arteries are called end arteries. Narrowing of these arteries therefore puts the heart tissue at risk of ischemic injury (Ischemic heart disease -IHD). Also, unlike other parts of the body which get continuous blood supply, the muscle layer of the heart only gets blood supply in pulses. This is because each time the heart muscles contract (systole), they squeeze the arteries running through them and temporarily stop blood flow, when they relax (diastole), the arteries become patent again and blood flows to supply the muscles and inner lining of the heart. [An average heart contracts and relaxes about 70 times each minute]. This intermittent oxygen supply contributes to the susceptibility of the hard working heart muscles to hypoxic damage. Fortunately, the heart muscles are capable of extracting more oxygen from blood than any other tissue in the body. Also, the blood flow to the heart increases almost proportionately to increase in workload and corresponding increase in oxygen consumption, by dilatation of the coronary arteries. These measures normally prevent hypoxia and tissue damage.

Patrick J. Lynch, medical illustrator

Coronary arteries may become narrowed or blocked by plaques (in coronary artery disease), blood clot building over a ruptured plaque or rarely, loose clot (embolus) formed within a heart with damaged valve or wall and carried in blood into the aorta.  Narrowing can also occur due to spasm of the artery. A plaque is mainly composed of fat (in form of cholesterol), calcium and fibrous tissue. Plaques take years to develop. They are commonly seen with ageing but may occur in younger people with high cholesterol levels, diabetes mellitus or hypertension.   The presence of plaques in any artery is called atherosclerosis- meaning hardened artery. Apart from narrowing the lumen, the plaque also hardens the walls of the artery preventing it from dilating to supply more blood in response to increased oxygen demand.

However, even in the presence of a plaque, symptoms of ischemia do not occur until about 70% of the lumen of the artery is occluded. The individual experiences squeezing chest pain (angina) brought on by any increase in workload on the heart such as with exertion (e.g. climbing stairs, physical exercise), in cold weather, emotional situations etc., and relieved by rest. If the plaque ruptures, a raw surface is exposed on the arterial wall and this stimulates the formation of a blood clot much like a bleeding injury anywhere in the body. This further narrows the lumen; worsening the angina which may now occur even at rest. Sometimes, the clot or thrombus can grow large enough to completely occlude the artery, totally depriving the part of the heart muscle (supplied by this artery) of oxygenated blood. This is what is referred to as a heart attack.

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See Heart attack (2)

click here to know your risk for heart disease

FROM SORE THROAT TO HEART DISEASE

(RHEUMATIC HEART DISEASE)

Rheumatic heart disease is a permanent heart valve damage resulting from one or repeated episodes of rheumatic fever. Acute rheumatic fever is an abnormal immune response by the body to an infection (usually a throat infection) caused by bacteria called group A streptococci. Normally, one of the ways in which the body fights infections is by producing antibodies which attack the infecting organisms. In acute rheumatic fever, the antibodies produced are thought to also attack the host’s tissues (brain, skin, subcutaneous tissues, joints and heart) causing an inflammatory damage several weeks after the throat infection. This autoimmune response is seen in about 0.3-30% of patients with untreated or poorly treated group A streptococcal throat infection. Rheumatic heart disease is the most serious complication of rheumatic fever. Almost half of patients with acute rheumatic fever will have the heart involvement.

Heart valve affected by RHD

The most commonly affected valve is the mitral valve followed by the aortic valve. Other valves (tricuspid and pulmonary are less frequently affected).The damage causes the flaps of the valve to thicken causing narrowing of the valve opening (stenosis). Repeated episodes of rheumatic fever further damage the valves and eventually lead to heart failure as less blood is pumped out of the heart but rather backs up in the left atrium, pulmonary veins and lungs. At this stage, except the valves are replaced with prosthesis, the patient will die of consequences of the heart failure. During an acute episode of rheumatic fever, the valvular damage may be minor and still be reversible. Symptoms of rheumatic heart disease include: shortness of breath, fatigue, irregular heartbeats, chest pain and fainting.

 

Rheumatic fever is principally a childhood disease; sore throat in children should therefore be taken seriously especially if there are no symptoms suggesting that it’s viral in origin. Such symptoms include runny nose, itchy eyes and other symptoms of the common cold. On the other hand, symptoms and signs which are considered as hall marks of streptococcal sore throat include a history of close contact with infected person, tender lymph nodes, skin rash (scarlet fever), swollen tonsils with whitish exudates and abdominal pain, with or without fever.

Tonsils are enlarged and have exudates

 

SCARLET FEVER RASH

However, a better and surer way to distinguish between a viral and a streptococcal sore throat is to go to the clinic and have a throat swab done.

An episode of acute rheumatic fever can go unnoticed. Symptoms however include fever, pain and swelling of the joints, nausea, stomach cramps and vomiting. These symptoms may be non specific, making diagnosis difficult.  A set of criteria have been developed to help doctors in diagnosing rheumatic fever.  The major criteria include: carditis, polyarthritis, chorea, subcutaneous nodules, and erythema marginatum. Minor criteria include: previous rheumatic fever or rheumatic heart disease, arthralgia, fever, elevated erythrocyte sedimentation rate/positive C-reactive protein/ leukocytosis, and prolonged PR interval on an electrocardiogram. Two major criteria, or a combination of one major and 2 minor, provide reasonable evidence for a diagnosis of rheumatic fever.

RHD occurs all over the world but is more prevalent in developing countries in association with a)overcrowding: which facilitates the spread of the throat infection,b) poverty: which partially explains the untreated or poorly treated infections, and c)lack of access to health care facilities in some areas.

There are 2 levels of prevention of rheumatic heart disease. The first is Primary prevention. This involves the prompt administration of antibiotics (Penicillin) for suspected streptococcal sore throat. It prevents the development of acute rheumatic fever. The other is Secondary prevention. The aim is to prevent recurrent episodes of rheumatic fever in someone who has already had a first episode. This will reduce progression of heart disease. It involves the use of penicillin orally (daily) or as injection (monthly) continuously for at least 10 years after the episode of acute rheumatic fever. Secondary prevention is more difficult to comply with.

The lessons here are these:

• An “ordinary” sore throat may not be ordinary after all
• A stitch in time saves nine [and in this case, saves the entire garment]

 

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