Heart disease can affect any of the structures of the HEART and may affect more than one at a time. Heart attack is an imprecise term, and may refer to ANGINA PECTORIS (a symptom of pain originating in the heart) or to coronary artery thrombosis, also called myocardial infarction.
An abnormal rate or rhythm of the heartbeat. The reason is a disturbance in the electrical impulses within the heart. Sometimes a person may have an occasional irregular heartbeat: this is called an ECTOPIC beat (or an extrasystole), and does not necessarily mean that an abnormality exists. There are two main types of arrhythmias: bradycardias, where the rate is slow – fewer than 60 beats a minute, and sometimes so slow and unpredictable (heart block) as to cause blackouts or heart failure; and tachycardia, where the rate is fast – more than 100 beats a minute. A common cause of arrhythmia is coronary artery disease, when vessels carrying blood to the heart are narrowed by fatty deposits (ATHEROMA), thus reducing the blood supply and damaging the heart tissue. This condition often causes myocardial infarction, after which arrhythmias are quite common and may need correcting by DEFIBRILLATION (application of a short electric shock to the heart). Some tachycardias result from a defect in the electrical conduction system of the heart, and this is commonly congenital. Various drugs can be used to treat arrhythmias (see ANTIARRHYTHMIC DRUGS). If attacks constantly recur, the arrhythmia may be corrected by electrical removal of dead or diseased tissue that is the cause of the disorder. Heart block is most effectively treated with artificial CARDIAC PACEMAKERS, a battery-activated control unit implanted in the chest.
Any disease of the heart muscle that results in weakening of its contractions. The consequence is a fall in the efficiency of the circulation of blood through the lungs and remainder of the body structures. The myopathy may be due to infection (usually viral), disordered metabolism, nutritional excess or deficiency, toxic agents, autoimmune processes, degeneration, or inheritance.
The three recognised groups of cardiomyopathies are hypertrophic, dilated and restrictive.
Hypertrophic myopathy, a FAMILIAL condition, is characterised by great enlargement of the muscle of the heart VENTRICLES. This reduces the muscle's efficiency; the ventricles fail to relax properly and do not fill sufficiently during DIASTOLE.
In the dilated type of cardiomyopathy, both ventricles overdilate, impairing the efficiency of contraction and causing congestion of the lungs.
In the restrictive variety, proper filling of the ventricles does not occur because the muscle walls are less elastic than normal. The result is raised pressure in the two ATRIA of the heart: these dilate and develop FIBRILLATION. Diagnosis can be difficult and treatment is symptomatic, with a poor prognosis. In suitable patients, heart TRANSPLANTATION may be considered.
Disorders of the heart muscle may also be caused by poisoning – for example, heavy consumption of alcohol. Symptoms include tiredness, palpitations (quicker and sometimes irregular heartbeat), chest pain, difficulty in breathing, and swelling of the legs and hands due to accumulation of fluid (OEDEMA). The heart is enlarged (as shown on chest X-ray) and ECHOCARDIOGRAPHY indicates thickening of the heart muscle. A BIOPSY of heart muscle will show abnormalities in the cells of the heart muscle.
Where the cause of cardiomyopathy is unknown, as is the case with most patients, treatment is symptomatic using DIURETICS to control heart failure and drugs such as DIGOXIN to return the heart rhythm to normal. Patients should stop drinking alcohol. If, as often happens, the patient's condition slowly deteriorates, heart transplantation should be considered.
accounts for 1–2 per cent of all cases of organic heart disease. It may be genetically determined, for example in DOWN'S SYNDROME; present at birth for no obvious reason; or, in rare cases, related to RUBELLA in the mother. The most common forms are holes in the heart (atrial septal defect, ventricular septal defect – see SEPTAL DEFECT), a patent DUCTUS ARTERIOSUS, and COARCTATION OF THE AORTA. Many complex forms also exist; these are sometimes diagnosed in fetus by echocardiography. Surgery to correct many of these abnormalities is feasible, even for the most severe abnormalities, but in some complex cases is only palliative. Heart transplantation is now increasingly employed for uncorrectable lesions.
Also known as ischaemic heart disease, this is a common cause of symptoms and death in the adult population. It may present for the first time as sudden death, but more usually causes ANGINA PECTORIS, myocardial infarction (death of heart muscle cells) or heart failure. It can also lead to a disturbance of heart rhythm. Factors associated with an increased risk of developing coronary artery disease include diabetes, cigarette smoking, high blood pressure, obesity, and a raised concentration of cholesterol in the blood. Older males are most affected.
More usually termed myocardial infarction (or STEMI, this is the acute, dramatic manifestation of coronary artery ischaemic heart disease – one of the major killing diseases of Western civilisation. Ischaemic heart disease was responsible for about 73,000 deaths in the UK each year, three-quarters in persons aged over 75; in all there has been a reduction of nearly 50 per cent over 25 years. The underlying cause is disease of the coronary arteries which carry the blood supply to the heart muscle (or myocardium). This results in narrowing of the arteries until finally they are unable to transport sufficient blood for the myocardium to function efficiently. One of three things may happen. If the narrowing of the coronary arteries occurs gradually, then the individual concerned will develop either ANGINA PECTORIS or signs of a failing heart: irregular rhythm, breathlessness, CYANOSIS and OEDEMA.
If the narrowing occurs suddenly or leads to complete blockage (occlusion) of a major branch of one of the coronary arteries, then the victim collapses with acute pain and distress. This is the condition commonly referred to as a coronary thrombosis because it is usually due to the affected artery suddenly becoming completely blocked by THROMBOSIS. More correctly, it should be described as coronary occlusion, because the final occluding factor need not necessarily be thrombosis.
A wide range of factors play a part in inducing coronary artery disease. Heredity is important. It is more common in men than in women; it is also more common in those in sedentary occupations than in those who lead a more physically active life, and is more likely to occur in those with high blood pressure than in those with normal blood pressure (see HYPERTENSION). Obesity is a contributory factor. The disease is more common among smokers than non-smokers; it is also often associated with a high level of CHOLESTEROL in the blood, which in turn has been linked with an excessive consumption of animal, as opposed to vegetable, fats. In this connection the important factors seem to be the saturated fatty acids (low-density and very low-density lipoproteins [LDLs and VLDLs] – see CHOLESTEROL) of animal fats, which would appear to be more likely to lead to a high level of cholesterol in the blood than the unsaturated fatty acids of vegetable fats. As more research on the subject is carried out, the debate continues about the relative influence of the different factors.
The presenting symptom is the sudden onset, often at rest, of acute, agonising pain in the front of the chest. This rapidly radiates all over the front of the chest and often into the left arm. The pain is frequently accompanied by nausea and vomiting, so that suspicion may be aroused of some acute abdominal condition such as biliary colic (see GALL-BLADDER, DISEASES OF) or a perforated PEPTIC ULCER. The victim may go into SHOCK, with a pale, cold, sweating skin, rapid pulse and difficulty in breathing. There is usually some rise in temperature.
is immediate relief of the pain by injections of diamorphine. Current guidelines recommend that thrombolytic drugs should be given as soon as possible (‘rapid door to needle time’) and ARRHYTHMIAS corrected. OXYGEN is essential and oral ASPIRIN is valuable. Treatment within the first hour makes a great difference to recovery. Subsequent treatment includes the continued administration of drugs to relieve the pain; the administration of antiarrhythmic drugs, which may be necessary to deal with the heart failure and the irregular action of the heart that quite often develop; and the continued administration of oxygen. Patients are usually admitted to coronary care units, where they receive constant supervision. Such units maintain an emergency, skilled, round-the-clock staff of doctors and nurses capable of undertaking ANGIOPLASTY as first-line treatment or to refer for CORONARY ARTERY BYPASS GRAFTING (CABG).
Following recovery, there should be a gradual return to work, care being taken to avoid any increase in weight, unnecessary stress and strain, and to observe moderation in all things. Smoking must stop. In uncomplicated cases patients get up and about as soon as possible, most being in hospital for a few days and back at work in three months or sooner.
primarily affects the mitral and aortic valves which can become narrowed (stenosis) or leaking (incompetence). Pulmonary valve problems are usually congenital (stenosis) and the tricuspid valve is sometimes involved when rheumatic heart disease primarily affects the mitral or aortic valves. RHEUMATIC FEVER, usually in childhood, used to be a common cause of chronic valvular heart disease causing stenosis, incompetence or both of the aortic and mitral valves, but each valve has other separate causes for malfunction.
is more common with increasing age. When the valve is narrowed, the heart hypertrophies (becomes more muscular), but ultimately may fail. Symptoms of angina or breathlessness are common, and dizziness or blackouts (syncope) also occur. Replacing the valve is a very effective treatment, even with advancing age. Aortic stenosis may be caused by degeneration (senile calcific), by the inheritance of two valvular leaflets instead of the usual three (bicuspid valve), or by rheumatic fever. Aortic incompetence also ultimately leads to hypertrophy, but dilatation is more common as blood leaks back into the ventricle. Breathlessness is the more common complaint. The causes are the same as stenosis, but also include inflammatory conditions such as SYPHILIS, or ANKYLOSING SPONDYLITIS and other disorders of connective tissue. The valve may also leak if the aorta dilates, stretching the valve ring as with HYPERTENSION, aortic ANEURYSM and MARFAN'S SYNDROME – an inherited disorder of connective tissue that causes heart defects. Infection (endocarditis) can worsen, acutely or chronically, destroy the valve and sometimes lead to abnormal outgrowths on the valve (vegetations) which may break free and cause devastating damage such as a stroke or blocked circulation to the bowel or leg.
leading to stenosis occurs as the end result of RHEUMATIC FEVER. Mitral incompetence may be rheumatic but, in the absence of stenosis, can be due to ISCHAEMIA, INFARCTION, inflammation, infection and a congenital weakness (prolapse). The valve may also leak if stretched by a dilating ventricle (functional incompetence). Infection (endocarditis) may affect the valve in a similar way to aortic disease. Mitral symptoms are predominantly breathlessness, which may lead to wheezing or waking at night, needing to sit up or stand for relief. The symptoms are made worse when the heart rhythm changes (atrial fibrillation), which occurs frequently as the disease becomes more severe. This leads to a loss of efficiency of up to 25 per cent, and a predisposition to clot formation as blood stagnates rather than leaving the heart efficiently.
is an infection of the lining of the heart which may acutely destroy a valve or may lead to chronic destruction. Bacteria settle usually on a mild irregularity of the valve. Antibiotics taken at vulnerable times can prevent this (antibiotic prophylaxis) – for example, before tooth extraction. If established, lengthy intravenous antibiotic therapy may be needed and surgery can be advised. Complications include heart failure, shock, embolisation (generation of small clots in the blood), and cerebral (mental) confusion.
PERICARDITIS is an inflammation of the sac covering the outside of the heart. The sac becomes roughened and pain occurs as the heart and sac rub together. This is heard by stethoscope as a scratching noise (pericardial rub). Fever is often present and a virus the main cause. It may also occur with rheumatic fever, kidney failure, TUBERCULOSIS or from an adjacent lung problem such as PNEUMONIA or cancer. The inflammation may cause fluid to accumulate between the sac and the heart (effusion), which may compress the heart and cause a fall in blood pressure, a weak pulse and circulatory failure (tamponade). This can be relieved by aspirating the fluid. The treatment is then directed at the underlying cause.