Glossary

ACE inhibitors

Angiotensin converting enzyme inhibitors. They help to inhibit the production of chemicals in the body which constrict blood vessels, and are commonly used in the treatment of hypertension and congestive heart failure.
Adrenaline
A hormone which is secreted by the adrenal medulla in response to stress and which increases the heart rate, pulse rate, and blood pressure.
Angina
Short for angina pectoris. Pain in the chest caused by insufficient blood flow to the heart muscle.
Angiocardiography
Another term for coronary angiography. A method of detecting whether a person’s coronary arteries are narrowed or blocked. A dye is first introduced into the patient’s coronary arteries and heart through a catheter. X-rays are then taken as the dye moves through the heart and coronary arteries.
Angioplasty
Short for percutaneous transluminal coronary angioplasty (PTCA); also referred to as “coronary angioplasty” or “balloon angioplasty”. A procedure used to widen a blocked coronary artery at the point of narrowing by means of a small balloon attached to the tip of a catheter.
Anti-arrhythmic drugs
Medicines used to treat heart rhythm disorders.
Anticoagulant
An agent which retards the clotting of blood, but which does not dissolve existing clots. It tends to prevent new clots from forming and existing clots from becoming larger.
Antioxidant
A substance which prevents or delays the deterioration of an object, by the action of oxygen in the air.
Anti-platelet drugs
Drugs which reduce the tendency of blood to clot. They act by reducing the “stickiness” of the platelets in blood.
Aorta
The largest artery in the body; also the artery which carries oxygenated blood out of the heart for distribution to other parts of the body.
Aortic stenosis
Abnormal narrowing of the aortic valve. It may arise as a congenital heart defect.
Aortic valve
The valve separating the aorta from the left ventricle of the heart.
Arrhythmia
An irregular heart rhythm.
Artery
A vessel which conveys blood away from the heart to other parts of the body. It generally carries blood which is rich in oxygen. The exception in humans is the pulmonary artery which transports deoxygenated blood from the right side of the heart to the lungs.
Atherosclerosis
The accumulation of fatty deposits on the walls of arteries.
Atria (sg. atrium)
The upper cavities of the heart. They receive blood that is being returned to the heart. The left atrium contains oxygen-rich blood flowing back from the lungs, while the right atrium contains deoxygenated blood from other parts of the body.
Atrial fibrillation
An irregular heartbeat caused by the atria failing to contract as they should. In patients with this condition, the atria merely “flutter” instead of contracting.
Atrial septal defect
A congenital heart defect in the form of a hole between the two atria.
Balloon angioplasty
Colloquial term for percutaneous transluminal coronary angioplasty (PTCA), a procedure used to widen a narrowed coronary artery by means of a small balloon attached to the tip of a catheter.
Beta-blockers
Compounds which block the action of adrenaline at the beta-receptors on heart muscle cells. They reduce the heart rate, the force of heart muscle contractions, and the heart’s oxygen needs such that the heart is able to pump blood around the body more efficiently. They are often used to treat high blood pressure, angina, heart failure, and arrhythmias.
Bicuspid valve
The heart valve which separates the left atrium from the left ventricle. Also known as the mitral valve.
Blood cholesterol
The total amount of cholesterol in the bloodstream.
Body Mass Index (BMI)
The standard adopted by the World Health Organization for the classification of body weight categories. BMI, which measures a person’s weight in relation to his height, is calculated using the formula:
BMI = weight (in kg) divided by [square of height (in m)]
Bradycardia
A heart rate that is unusually slow.
Bronchitis
Inflammation of the bronchial tubes characterised by coughing and breathing difficulties.
Calcium channel blockers
Compounds which block the effect of calcium on muscle fibre cells. They relax the muscles in the heart and blood vessels, thereby reducing blood pressure and heart rate. They are used in the treatment of high blood pressure, spasms of the coronary arteries, and angina caused by coronary heart disease.
Cardiac catheterisation
A procedure in which a catheter (thin tube) is passed through an artery in either the forearm or groin and then manoeuvred to the coronary arteries. It is used to detect areas where the coronary arteries are constricted and how narrow they have become.
Cardiac rehabilitation
The process of assisting recovering heart patients to resume, by their own efforts, as normal a life as possible. It includes physical exercise, nutritional and psychological counselling, as well as social and emotional support.
Cardiomyopathy
A generic term for diseases of the heart muscle. The most common form is dilated cardiomyopathy, in which the heart muscle is weakened, causing left ventricular dilation and, in turn, elevated diastolic blood pressure and volume.
Cardiopulmonary resuscitation (CPR)
A method of mouth-to-mouth breathing combined with external chest compressions which is used to keep oxygenated blood circulating in the body when the heart stops beating.
Carotid arteries
The two arteries carrying blood from the heart to the head and neck.
Catheter
A long, thin, flexible tube which can be inserted into a blood vessel in the arm or groin and threaded through to the heart.
Cholesterol
A waxy, fat-like compound found in animal products such as animal fats/oils, milk, and egg yolks. It can also be found in various organs and cells in the human body including the myelin sheaths of nerve fibres, liver, kidney, and adrenal glands.
Congenital heart disease
A defect of the heart which is present at the time of a person’s birth.
Congestive heart failure
A condition in which the heart is unable to pump out blood effectively, leading to the accumulation of blood and fluid in the lungs and other organs.
Coronary angiography
Another term for angiocardiography. A test which shows whether a person’s coronary arteries are narrowed or blocked by taking X-rays of these arteries after injecting a dye into them.
Coronary angioplasty
Short for percutaneous transluminal coronary angioplasty (PTCA) or “balloon” angioplasty. It is a method of improving blood supply to heart muscle. This is done by inserting a catheter (thin tube) with a small inflatable balloon at its tip into an artery in the forearm or groin and threading it (the catheter) through a narrowed coronary artery. The balloon is then inflated so that it compresses the fatty deposits responsible for the constriction, thereby widening the affected artery.
Coronary arteries
The two arteries branching from the aorta and supplying blood to the heart.
Coronary artery bypass grafting (CABG)
An operation carried out to bypass a constricted section of a coronary artery by grafting a section of a healthy blood vessel from another part of the patient’s body.
Creatinine kinase
An enzyme of contractile muscle cells which may be found in the bloodstream after a heart attack.
CT scan
Short for computed tomography scan. A scanning method used to capture cross-sectional images of the patient’s heart and its surrounding blood vessels.
Defibrillator
An electrical device used to restore normal heart contraction rhythms. This is done by delivering a carefully regulated electrical current to the heart when it suddenly stops beating effectively.
Diabetes
An endocrinological disorder which results in the body being unable to metabolise glucose due to insulin deficiency.
Diastole
The period of relaxation and dilation of the chambers of the heart in between contractions of heart muscle.
Diastolic blood pressure
The lower of the two readings recorded when measuring blood pressure. It reflects the pressure exerted by blood when the heart relaxes and opens its chambers in between beats.
Diuretics
Substances which increase the output of water and salt in the urine; also referred to as “water tablets”.
ECG
Short for electrocardiogram or electrocardiography. A test which records the electrical activity of the heart. The printout of the heart’s electrical pulses as recorded during the test is referred to as the electrocardiogram.
Echocardiography
A procedure in which sound pulses are emitted into the body and the resultant echoes from the heart recorded and plotted.
Endocardium
The innermost layer of the wall of the heart.
Endothelium
The inner lining of blood vessels.
Epicardium
The outermost layer of the wall of the heart.
Exercise heart rate
The heart rate which one should attain during exercise in order to maximise cardiovascular benefits. It is pegged at 60-80% of a person’s maximum heart rate (defined as 220 minus his age).
Exercise stress test
A test used to determine how well a person’s heart responds to the stress arising naturally from exercise. It usually involves the person running on a treadmill as his heart rate is monitored by an electrocardiography machine.
Exercise tolerance
The amount of physical activity which a person can undertake without developing breathing difficulties or physical discomfort.
Fibrin
An insoluble protein formed during the normal clotting of blood.
Haemorrhagic stroke
A stroke which is caused by the rupturing of one or more blood vessels in the brain.
HDL
Short for high-density lipoproteins. The type of lipoproteins which transports fat and cholesterol back to the liver for breakdown, thus “cleansing” the arteries.
HDL cholesterol
High-density lipoprotein cholesterol; also known as “good” cholesterol. It refers to cholesterol which is being transported by HDL (high-density lipoproteins) away from blood vessels for excretion from the body.
Healthy Diet Pyramid
A diet based on the classification of food into various food groups, namely: (i) rice and other forms of carbohydrate; (ii) fruits; (iii) vegetables; (iv) meat and alternative forms of protein; and (v) seasonings such as fat, oils, sugar, and salt. It advocates the consumption of more energy from the food groups on the lower tiers of the Pyramid (i.e. carbohydrate, fruits, and vegetables); less from the meat/protein food group which is placed higher up the Pyramid; and least from fats, oils, sugar, and salt which together make up the tip of the Pyramid.
Heart failure
Another term for congestive heart failure. A condition in which the heart is unable to pump sufficient blood to meet the oxygen requirements of other organs in the body.
Heart-lung machine
An apparatus which oxygenates and pumps blood during open-heart surgery and heart transplants.
Holter monitoring
Electrocardiogram monitoring done over time, usually over a 24-hour period.
Hormone replacement therapy (HRT)
A form of oestrogen treatment which is used to control menopausal symptoms and prevent osteoporosis.
Hydrogenated fat
Unsaturated fat to which hydrogen has been added to make it more stable and solid at room temperature.
Hypertension
Also known as high blood pressure. A condition in which the sufferer has a blood pressure reading of 140/90 mm Hg.
Immunosuppressants
Medicines prescribed to suppress the body’s natural immune system, especially in order to reduce the likelihood of rejection of a transplanted organ.
Insulin
A hormone secreted in the pancreas. It controls the concentration of glucose in the blood.
Ischaemic stroke
A stroke caused by obstruction in one or more of the blood vessels supplying blood to the brain.
LDL
Short for low-density lipoproteins. The type of lipoproteins which transports fat and cholesterol from the liver to other parts of the body where they may deposit on the inner walls of arteries and, with time, result in atherosclerosis.
LDL cholesterol
Low-density lipoprotein cholesterol. It refers to “bad” cholesterol which builds up within the lining of arteries, leading to various forms of heart disease.
Lipoproteins
The biochemical agents responsible for transporting fat and cholesterol in the human body. They are formed when fat and cholesterol, which are not water-soluble combine with water-soluble proteins.
Menopause
The stage in a woman’s life during which her menstrual cycle stops. It normally occurs at the age of 45 to 50.
Mitral valve
The valve which separates the left atrium from the left ventricle. Also known as the bicuspid valve.
Monounsaturated fat
A form of fat, the molecules of which have long chains of carbon containing only one (“mono-“) double bond. It is found in liquid form at room temperature.
MRI
Short for magnetic resonance imaging. A method of producing three-dimensional, high-resolution images of internal body structures through the use of powerful magnets.
Myocardial infarction
Another term for heart attack. A cardiac event caused by insufficient, or complete cessation of blood flow to the heart such that the heart muscle in the affected area begins to die.
Myocardium
Middle layer of the heart’s wall; also the layer which provides the heart with the muscular strength to pump blood around the body.
Nuclear imaging
The capturing of computer-generated images and scans of a person’s heart based on fluorescence emitted by radioactive substances which have been injected into his bloodstream.
Oedema
Excessive accumulation of fluid in the intercellular spaces of tissue.
Oesophagus
That part of the alimentary canal between the pharynx (throat) and the stomach.
Osteoporosis
Porosity and brittleness of the bones caused by the loss of calcium from the bone matrix.
Oestrogen
A hormone which stimulates changes in female reproductive organs, induces oestrus, and promotes the development of other female secondary sexual characteristics.
Pacemaker
An electrical appliance used to stimulate contractions of the heart.
Percutaneous transluminal coronary angioplasty (PTCA)
Another term for coronary or “balloon” angioplasty.
Pericardium
A membranous sac which encloses the heart.
Platelets
Minute particles present in the blood of vertebrates and involved in the clotting of blood.
Polyunsaturated fat
A type of animal and vegetable fat, the molecules of which consist of long carbon chains with several (“poly-“) double bonds. It is less likely to be converted into cholesterol in the body. It may be found in either a liquid or soft solid form at room temperature.
Progestin
Any of a group of steroid hormones with progesterone-like activity in terms of preparing and maintaining the uterus in females for pregnancy.
Pulmonary arteries
The arteries which carry deoxygenated blood from the right side of the heart to the lungs for oxygenation.
Pulmonary stenosis
Abnormal narrowing of the pulmonary valve. It may arise as a congenital heart defect.
Pulmonary valve
The valve between the pulmonary artery and the right ventricle.
Pulmonary veins
The veins which carry oxygen-rich blood from the lungs back to the left side of the heart.
Rheumatic fever
A disease characterised by fever and pain of the joints; it can cause damage to the heart valves.
Saphenous vein
The long superficial vein which runs along the inner side of the leg.
Saturated fat
Fat which contains a high proportion of fatty acids having single bonds. It is found as a firm solid at room temperature.
Septum
Muscular wall dividing the chambers of the heart.
Sinus / Sinoatrial node
A small bundle of muscle fibres and nerves located in the right atria. It acts as the heart’s natural pacemaker.
Spectral Doppler echocardiography
A method of analyzing the speed and direction of blood flow in a person’s cardiovascular system through the use of sound waves.
Stent
An expandable metal tube such as a coil or wire mesh. It is typically inserted into a coronary artery after angioplasty to act as a “scaffolding” keeping that artery open.
Stroke
A cardiovascular disorder which occurs when a blood vessel supplying oxygen to the brain bursts or becomes blocked. Once deprived of oxygen, the nerve cells in the brain cannot function and begin to die, thus impairing the functions of those parts of the body which they control.
Systole
A period of contraction of the heart muscle during which blood is expelled from the ventricles.
Systolic blood pressure
The higher of the two readings recorded when measuring blood pressure. It reflects the pressure with which the heart contracts and pumps blood to the rest of the body.
Tachycardia
Abnormally fast heart rate.
Tetralogy of Fallot
A congenital malformation of the heart in which there is pulmonary stenosis (narrowing of the pulmonary artery) and a large hole between the ventricles.
Thrombosis
Formation or presence of a blood clot.
Thrombus
A clot of coagulated blood that forms within a blood vessel or inside the heart, often impeding the flow of blood.
TIA
Transient ischaemic attack. A minor stroke which causes stroke-like symptoms but no lasting damage. It is an important predictor of stroke.
Transplantation (heart)
The transfer of a healthy heart from a donor to a cardiac patient when the latter’s heart can no longer function sufficiently to keep him alive.
Troponin
A protein which inhibits the contraction of muscle tissue.
Valve
A flap-like structure in the heart which controls the one-way passage of blood through the organ.
Vein
A vessel which conveys blood back to the heart. It generally carries deoxygenated blood, except for the pulmonary vein in humans which transports oxygen-rich blood from the lungs back to the left side of the heart.
Vena cavae
Either of two large veins conveying deoxygenated blood to the heart. The superior vena cava carries blood from the upper part of the body (i.e. from the head, neck, and chest area upward of the fifth lumbar vertebra), while the inferior vena cava carries blood from the lower part of the body (i.e. downward from the fifth lumbar vertebra).
Ventricles
The two lower chambers of the heart which hold blood to be pumped out of the heart. The right ventricle contains deoxygenated blood which is to be transported via the pulmonary arteries to the lungs. The left ventricle, in contrast, holds oxygenated blood to be distributed to other parts of the body via the aorta.
Ventricular fibrillation
A potentially fatal form of ventricular tachycardia in which the ventricles flutter so rapidly that they hardly pump any blood.
Ventricular septal defect
A congenital heart defect in the form of a hole between the two ventricles.
Ventricular tachycardia
An abnormally fast heart rate, usually of more than 120 beats per minute, which arises due to the ventricles beating too rapidly.