Operations available to treat heart disease and stroke range from relatively minor procedures such as angioplasties and the fitting of pacemakers, to heart transplants.
Pacemakers – Implantable defibrillators
An artificial pacemaker may be needed by patients with heart block or who have irregular heart rates or heart rhythms.
A pacemaking system has a pulse generator and one (single chamber) or two (dual chamber) electrode leads.
The pacemaker has a power supply or batteries and electronic circuitry, weighs about 20 to 50g and is almost completely hidden.
They last on average between six and 10 years.
Electrical impulses are conducted down the electrode lead to the heart, stimulating heartbeats.
Some pacemakers discharge electrical impulses at a fixed rate, but most work on demand.
The pacemaker may be fitted under local anaesthetic when an electrode lead is inserted into a vein at the shoulder or the base of the neck and guided into the correct chamber of the heart using an X-ray screen.
The electrode may alternatively be attached directly onto the outer surface of the heart. The pacemaker box is positioned under the skin of the abdomen.
There is a small danger of infection where the pacemaker is fitted.
Heart transplants
There are around 300 heart transplants carried out in the UK each year.
Heart transplants are usually carried out on people with severe heart failure caused by coronary heart disease or cardiomyopathy.
They can also be carried out for patients with severe abnormalities of the heart valves, congenital heart defects or an uncontrollable fast heart rhythm.
The average wait for a transplant once on the waiting list in the UK is six months. About 15% of patients die while on the waiting list.
The heart is stopped and a machine takes over the function of the heart and lungs. The diseased heart is removed and the donor organ sewn in and connected to the main blood vessels.
After the operation, immunosuppressant drugs are given to ensure the body does not try to reject the new heart. They must be taken for the rest of the patient’s life.
Rehabilitation programmes, including physiotherapy, begin shortly after the operation. Life should return to normal within six to eight weeks.
Between 50% and 60% of heart transplant patients are alive after 10 years.
Coronary angioplasty, and stents
There are 23,500 angioplasties performed on patients with angina in the UK each year. Nine out of 10 operations are successful.
Fatty tissue – atheroma – responsible for narrowing arteries, is squashed, allowing blood to flow more easily.
A catheter is inserted into an artery under local anaesthetic in either the groin or the arm and guided using an X-ray screen to a coronary artery until its tip reaches the narrowed or blocked section.
A balloon mounted on the end of the catheter is then gently inflated to a diameter of about 3mm, flattening the atheroma.
A short tube of stainless steel mesh – a stent – may be inserted into the part of the artery to be widened to prevent re-narrowing after angioplasty.
Ultrasound and laser angioplasty can also be used but are rare.
Coronary bypass surgery
Coronary bypass surgery is used to bypass the narrowed sections of coronary arteries by grafting a blood vessel between the aorta – the main artery leaving the heart – and a point in the coronary artery beyond the narrowed or blocked area.
More than 21,000 patients have coronary artery surgery in the UK each year. The risk of death within a month of the operation is 2%.
The graft to be used comes from another blood vessel within the patient’s body.
An incision is usually made in the middle of the chest and the breastbone split lengthways.
Keyhole surgery, which involves less opening of the chest, remains rare and is currently being evaluated.
During the operation, a heart lung bypass machine takes over the pumping of blood and breathing.
Around eight in 10 patients experience immediate and lasting relief from angina. Most of the others find the bypass improves their angina, says the British Heart Foundation.
Atherectomy
Atherectomy uses a rotating shaver on the end of a catheter, introduced through a blood vessel in the leg or arm, which is fed through to the blocked coronary artery.
The high-speed rotating device at the tip of the catheter grinds the plaque into minute particles, clearing the artery. Balloon angioplasty may then be used on the artery.
Heart valve replacement
Heart valve surgery may be required if drugs are unable to control the problem.
Valve replacement – Diseased valves are usually replaced by manufactured valves (artificial/mechanical valves), or animal valves (tissue valves/biological valves).
The valves open and close around 40m times a year. They can make a clicking sound.
Anticoagulants are taken with artificial valves because there is a risk of blood clots developing on the surface, but are not usually necessary with tissue valves.
Long-term survival rates for patients with either type of valve are similar. Eight out of 10 tissue valves are still working after 10 to 12 years.
Valve repair – Usually done only for the mitral valve – between the left atrium and left ventricle.
Congenital heart disease treatments
Arterial Switch – Where babies are born with the major arteries switched round, an operation is carried out to reverse the defect.
Balloon atrial sepostomy – The atrial opening is enlarged using a catheter to improve the oxygen supply in babies whose major arteries are transposed.
Balloon valvuloplasty – A catheter is inserted into the opening of a narrowed heart valve and a balloon opened to stretch the valve.
Fontan procedure or operation – The right atrium is connected to the pulmonary artery directly or with a conduit, allowing blood to bypass an incomplete or under-developed right ventricle.
The atrial defect is also closed to relieve blueness – cyanosis.
Pulmonary artery banding – A band is placed around the pulmonary artery to narrow it and reduce blood flow and high pressure in the lungs.
Band can later be removed and the defect fixed with open heart surgery.
Shunt or shunting procedure – A passage is formed between blood vessels to divert blood from one part of the body to another and reduce blueness in infants with severe Tetralogy of Fallot.
Venous switch or intra-atrial baffle – A tunnel is created inside the atria to help correct transposition of the major arteries.
Carotid endarterectomy
Build up of plaque in the carotid arteries – major blood vessels in the neck, taking blood from the heart to the brain – can be surgically removed by carotid endareterctomy to prevent a stroke.
http://news.bbc.co.uk/2/hi/health/medical_notes/g-i/764043.stm
Tag: Heart disease
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Heart Diseases-IX-Heart Diseases-operations.
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Heart disease VII-Diagnostic tests-BBC.
Tests to establish whether people are at risk of, or have suffered, heart disease or stroke can involve chemicals being injected into the body – invasive – or readings taken externally only – non-invasive.
Non-invasive
Electrocardiography
An electrocardiogram (ECG) measures the rhythm and electrical activity of the heart.
Small metal patches, called electrodes and set in sticky plaster, are put on the arms, legs and chest and connected by wires to a recording machine.
The test can detect abnormalities of heart rhythm and can tell whether the patient has had a heart attack in the past.
The test has limitations – abnormal readings can have an innocent explanation and some patients with serious heart problems can have a normal ECG.
Exercise ECG, otherwise known as exercise stress testing, is an ECG taken while exercising on a treadmill or stationary bicycle.
It is often more accurate than a resting ECG and is used to test whether there is a lack of blood supply through the arteries that go to the heart.
The exercise is made increasingly difficult and blood pressure and breathing are monitored at the same time.
Holter monitoring, also known as 24-hour ECG, involves electrocardiogram recordings taken over 24 hours and can help diagnose palpitations, which occur infrequently and can easily be missed in a short test.
The electrodes are placed on the chest and attached with wires to a small portable tape recorder which is worn on a belt around the waist.
The recorder – the Holter monitor – takes constant or intermittent readings.
Echocardiography
A pulse of high frequency, inaudible sound is transmitted through the skin by placing a recorder or probe on the chest wall.
The probe picks up the echoes reflected from various parts of the heart and displays them as an echocardiogram – a picture on a screen.
The recorded waves show the shape, texture and movement of the valves and the size and function of the heart muscle and chambers.
The test can take up to an hour and is painless.
It provides information about disease of the heart muscle for those who have suffered a heart attack or heart failure and to assess people with disease of the heart valves.
Doppler echocardiography measures the speed of the flow of blood in different parts of the heart.
Occasionally, echocardiography is carried out after the heart is put under stress either with exercise or a drug – stress echocardiography.
Magnetic Resonance Imaging (MRI scan)
Magnetic Resonance Imaging (MRI) produces detailed pictures of internal organs, including the heart and brain.
Patients lie in a short tunnel-like machine which contains a cylindrical magnet. Short bursts of magnetic fields and radio waves create images of parts of the body as required.
MRI can measure the flow of blood through some of the major arteries and can detect abnormal heart function in disorders such as cardiomyopathy (heart muscle disease), coronary heart disease, congenital heart defects and help define the location and extent of brain injury in stroke patients.
CT or CAT scan
High resolution images of the heart, brain and blood vessels are given by X-ray computed tomography (CT) or computerised axial tomographic (CAT) scans.
It is useful to evaluate disease of the aorta – the largest artery in the body and involves little potential risk to patients. In stroke patients, it gives valuable information about the location and extent of brain injury.
Blood tests – cardiac enzyme tests
Blood samples taken over a series of days can reveal the level of enzymes – proteins that help with chemical actions in the body and are released after a heart attack – in the blood.
Invasive
Coronary angiogram – cardiac catheterisation
Cardiac catheterisation is often used to assess whether people with angina require surgery.
The test gives vital information about blood pressure within the heart, how much oxygen is in the blood, the function of the pumping chambers and valves, and the exact severity and positioning of any narrowings in the coronary arteries.
A coronary angiogram – a picture of the coronary arteries – is produced.
The catheter – a long, flexible, plastic tube – is inserted into a vein or artery in the groin or the arm after a local anaesthetic is given.
The catheter is used to inject dye into the coronary arteries – this is called coronary angiography or coronary arteriograpy.
High speed X-ray “films” record the course of the liquid as it flows through the heart and arteries. Obstructions in the arteries can be identified by tracing the liquid’s passage.
Cerebral arteriography is used to show the extent and location of hardening of the arteries in the brain in order to diagnose patients at risk of stroke.
The test takes between 20 minutes and an hour and is often done as day case, though some patients may have a short stay in hospital.
There is a very small risk – one in 700 – that the test will cause a heart attack.
Nuclear imaging
A very small and harmless quantity of radioactive substance, called an isotope, is injected into the blood, often while exercising.
Gamma rays emitted by the isotope – usually technetium or thallium – are picked up by a “camera” positioned close to the chest.
Technetium is used to test the size and pumping function of the heart chambers, taking pictures of the inside of the heart as it empties and fills.
Thallium is used to study the blood flow to the heart muscle, by taking pictures of the flow of blood to the muscular walls of the heart, and to provide more detailed information than the exercise ECG test.
http://news.bbc.co.uk/2/hi/health/medical_notes/g-i/764038.stm -
Heart Disease VI-Risk factors and prevention-BBC.
Heart disease and stroke may be inherited, but often they are the result of lifestyle. Changing eating, exercise and smoking habits can play a significant part in prevention.
Risk Factors
Age
Four out of five people who die from coronary heart disease are aged 65 or older. The risk of stroke doubles with each decade after the age of 55.
Sex
Men are more at risk than women and have attacks earlier in life. But death rates from heart disease and stroke for women are twice as high as those for all forms of cancer.
The risk for women increases as they approach menopause and continues to rise a they get older, possibly because of the loss of the natural hormone oestrogen.
Family history (heredity)
Children of parents with heart disease are more likely to suffer from the disease. Some races, such as Afro-Caribbeans, are more prone to coronary heart disease and stroke than others.
Smoking
Smokers are twice as likely to suffer heart attacks as non-smokers, and they are more likely to die as a result. Smoking is also linked to increased risk of stroke.
The nicotine and carbon monoxide in tobacco smoke damages the cardiovascular system. Passive smoking may also be a danger.
Women who smoke and take the oral contraceptive pill are at high risk of heart disease and stroke.
Alcohol
Drinking an average of more than one drink a day for women or more than two drinks a day for men increases the risk of heart disease and stroke because of the effect on blood pressure, weight and levels of triglycerides – a type of fat carried in the blood.
Binge drinking is particularly dangerous.
Drug abuse
The use of certain drugs, particularly cocaine and those taken intravenously, has been linked to heart disease and stroke.
Cocaine can cause abnormal heartbeat, which can be fatal, while heroin and opiates can cause lung failure. Injecting drugs can cause an infection of the heart or blood vessels.
Cholesterol
The higher the blood cholesterol level, the higher the risk of coronary heart disease, particularly if it is combined with any of the other risk factors. Diet is one cause of high cholesterol – others are age, sex and family history.
High levels of LDL (low-density lipoprotein), or “bad cholesterol”, are dangerous, while high levels of HDL (high-density lipoprotein), or “good cholesterol” lower the risk of heart disease and stroke.
Blood pressure
High blood pressure increases the heart’s workload, causing it to enlarge and weaken over time. When combined with obesity, smoking, high cholesterol or diabetes, the risk increases several times.
High blood pressure can be a problem in women who are pregnant or are taking high-dose types of oral contraceptive pill.
Physical inactivity
Failure to exercise is a cause of coronary heart disease as physical activity helps control cholesterol levels, diabetes and, in some cases, can help lower blood pressure.
Obesity
People who are overweight are more likely to develop heart disease and stroke, even if they have none of the other risk factors.
Excess weight causes extra strain on the heart, influences blood pressure, cholesterol and levels of other blood fats – including triglycerides – and increases the risk of developing diabetes.
Diabetes
The condition seriously increases the risk of developing cardiovascular disease, even if glucose levels are under control. More than 80% of diabetes sufferers die of some form of heart or blood vessel disease.
Previous medical history
People who have had a previous heart attack or stroke are more likely than others to suffer further events.
Stress
Some links have been made between stress and coronary artery disease. This could be because it encourages people to eat more, start smoking or smoke more than they would otherwise have done.
Prevention
Education
Educating people about the risk factors of heart disease and stroke and attempting to persuade them to adopt a healthier lifestyle can have an impact on the number of people dying from heart disease and stroke.
Encouraging people to stop smoking, drink less, eat better and exercise regularly are particularly important.
Doctors can help by asking about smoking habits and encouraging patients to use nicotine replacement treatment, such as nicotine patches.
Regular monitoring
People should also have regular blood pressure readings, height and weight monitoring, and tests for cholesterol levels.
Those with high levels should be encouraged to improve their diet and can be treated for poor cholesterol levels with drugs – usually, statins or niacins.
The American Heart Association recommends that blood pressure should be no more than 140 over 90 Hg.
The association recommends a series of diets, with no more than 30% of calories coming in the form of fats, and limiting calories in the form of saturated fats to between 7 and 10%.
People at risk should have less than 200mg dietary cholesterol per day.
Sodium intake, most commonly found in salt, should also be controlled.
Exercise
Between three and four sessions of moderate intensity exercise, lasting around 30 minutes a time, are recommended as the minimum for physical activity each week.
Ideal body mass index (BMI) – calculated by dividing weight in kilograms by the square of height in metres – is between 21 and 25, and the preferable waist circumference is no more than 88cm (35 inches) for women, 102cm (40 inches) for men.
For people already suffering from cardiovascular disease, the use of aspirin or warfarin, both of which prevent blood clotting, is recommended.
Other drugs, including ACE (angiotensin-converting enzyme) inhibitors to manage blood pressure, beta-blockers to control angina, heart rhythm or blood pressure, and oestrogen replacement in post-menopausal women, may also be used to prevent repeat incidents.
http://news.bbc.co.uk/2/hi/health/medical_notes/g-i/764037.stm -
Health V-Stroke – haemorrhagic-BBC.
In around 20% of cases, strokes are caused by ruptured blood vessels leaking blood into the brain – haemorrhagic strokes.
Both types of stroke – those caused by blood clots and those caused by burst blood vessels – interrupt the supply of blood to the brain, depriving the cells of oxygen and other nutrients. The cells are then damaged or die.
Strokes caused by the breakage or “blow-out” of a blood vessel in the brain are the result of a cerebral aneurysm – ballooning of a weakened blood vessel in the brain – which is left untreated, high blood pressure, or a cluster of abnormally formed blood vessels (arteriovenous malformation).
Aneurysms develop over a number of years and do not usually cause detectable problems until they break.
Types of haemorrhagic stroke
There are two types of haemorrhagic stroke – subarachnoid and intracerebral.
In an intracerebral haemorrhage bleeding occurs from vessels within the brain itself. Hypertension, or high blood pressure, is the primary cause of this type of haemorrhage.
In subarachnoid haemorrhage, an aneurysm bursts in a large artery on or near the delicate membrane surrounding the brain. Blood spills into the area around the brain which is filled with a protective fluid, causing the brain to be surrounded by blood-contaminated fluid.
The symptoms of stroke:
Sudden numbness or weakness of the face, arm or leg, particularly if it is on one side of the body
Sudden confusion, trouble speaking or understanding. Sudden difficulty with walking, dizziness, loss of balance or co-ordination
Sudden trouble seeing in one or both eyes
Sudden severe headache with no known cause
Anyone identifying themselves or friends or family as having a stroke should call emergency services, not a GP, as any delay reduces the chance of a full recovery.
Treatment
The speed of treatment after a stroke is extremely important as the longer the brain cells are deprived of oxygen, the more damage they will suffer.
Clot-busting drugs and aspirin must not be given to patients who have suffered a haemorrhagic stroke. A CT scan or MRI scan will identify the type of stroke suffered.
Treatment of haemorrhagic stroke is less developed than that of ischaemic stroke.
A Medical Research Council trial is currently underway into treatment to remove blood clots surgically and drugs which prevent damage to brain cells during haemorrhages are being tested.
Survival rates are better for patients in specialist stroke units, because of the expert nature of staff and early use of rehabilitation, but such units are not always available.
Rehabilitation programmes will be given to most stroke patients to help them recover lost mobility and speech.
http://news.bbc.co.uk/2/hi/health/medical_notes/g-i/764071.stm -
Heart disease-3–Stroke-BBC.
On stroke.
STROKE
There are two types of stroke – those caused by blood clots in the brain and those that occur when blood vessels burst. In both cases, the brain is starved of oxygen, damaging or killing cells.
Sufferers are often left with difficulty talking, walking and performing other basic tasks. The chance of suffering a stroke is cut by eating healthily, quitting smoking and drinking less alcohol. People at risk of stroke are often treated with aspirin.
After a stroke, various drug treatments are available and rehabilitation is commonly used to improve patients’ speech and movement.
http://news.bbc.co.uk/hi/english/static/in_depth/health/2000/heart_disease/stroke.stm
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