Glossary Of Terms - D

Death rates DC cardioversion Deep vein thrombosis Dermatitis Diabetes Diet
Disability Diuretic Docosahexaenoic acid DHA Doctor Donor Donor Register
Double-blind trial Drip Drug Drugs - finding in this Glossary Drug-eluting stent Dyspnoea

Dabigatran versus warfarin for patients with Atrial Fibrillation. Atrial fibrillation AF (irregular heart rhythm) increases the risks of stroke and death if not treated. Warfarin reduces blood clotting. Clots can break off and cause blockage in flow to lungs, heart or brain, so AF patients at risk of stroke have had warfarin.

In trials on patients with AF, warfarin reduced strokes per patient year (ppy) from 6.0% placebo to 2.2%. Low-dose aspirin or antiplatelet agents reduced AF patient strokes from 6.7% to 5.3% ppy. Warfarin slightly increased major bleeding from 0.6% to 1.1% ppy. Warfarin interacts with some other drugs and needs frequent monitoring; so is often not used. A new effective, safe and convenient drug is needed.

Dabigatran is a new drug taken by mouth that thins blood and delays or reduces clotting, with half-life 12 to 17 hours.

In a randomised trial, AF patients on dabigatran at 110 mg had similar or lower rates of stroke and embolism than warfarin, and lower major bleeding. Those at 150 mg had lower rates of stroke and embolism, but similar rate of major bleeding. Both doses gave slightly more MI and pulmonary embolism than warfarin, and slightly fewer deaths.

In the UK dabigatran is currently used in hip surgery, but (2009) is not licensed for use in AF treatment. The drug is given in an inactive form called dabigatran etexilate. Etexilate means it turns into the active form in the patient’s body. NICE, the National Institute for Health and Clinical Excellence, is (Oct 2009) investigating dabigatran etexilate for treating venous thromboembolic events.

Danger. See Danger under First Aid.

Death rates. CHD and strokes are the major causes of disability and premature deaths in the UK.

For examples of advances in knowledge see Take both aspirin and a statin under Statin, and BHFNC under Exercise.

Deaths from circulatory diseases per 100,000 UK population have dropped slightly in recent years. The figures in the table are 2002.  

Deaths per 100,000 populationMales 1996Males 2002Females 1996Females 2002
From all causes104597510991034
From all circulatory diseases442385465404
From Ischaemic heart disease eg CHD273218220170
From Cerebrovascular disease eg stroke 8687141135

The other causes not included in the table are, in decreasing order: All malignant neoplasms eg cancers, Pneumonia, Bronchitis and allied conditions, Chronic liver disease and cirrhosis, All accidents and adverse effects, Suicide, and Diabetes mellitus. Source: Department of Health.

DC cardioversion uses a small electrical current through the front of the chest and thereby through the heart, which will hopefully bring the heartbeat pattern back to normal. DC means direct current.

In DC cardioversion a small amount of electricity is given through the front of the chest and thereby through the heart, which will hopefully spin it back to normal.

The procedure is very safe indeed. The commonest problem is minor irritation of the skin following the procedure. There is a very rare chance that any clot that may have previously formed within the heart could be dislodged by this procedure. Taking warfarin before the procedure minimizes this risk.

Everything is done as a day case and you will be allowed to go home in the evening, although you will not be allowed to drive. You should have someone to escort you home.

Deep vein thrombosis, DVT, means a blood clot in a leg. This can occur after surgery, long bed rest, or pregnancy; or may arise from genetic disorders. It also commonly occurs while or after sitting in a cramped situation and/or where unable to move around – especially on long flights or long car journeys.

One danger is that a blood clot produces an embolus that flows with the blood to the lungs or heart – producing a pulmonary embolism or blockage of a coronary artery and unfortunate death. The risk may continue for up to a fortnight after the flight or whatever. About 1 patient in 100 who develop DVT dies – a total of 500 to 1000 UK people per year. Patients who develop a swollen leg and go to see a doctor or hospital should tell the doctor if they have been flying in the previous fortnight, to alert the doctor to the situation.

Research showed that patients taking low-dose aspirin and who developed DVT were less likely to develop a dangerous pulmonary embolism.

Defibrillator. See Automatic external defibrillator.

Dependence means physical or psychological dependence on a substance, eg addiction.

Physical dependence means getting physical withdrawal symptoms such as sweating, abdominal pain, or convulsions if without the drug. Psychological dependence means mental craving if without the drug.

Dermatitis is a skin inflammation. Vitamin H prevents it and also helps avoid loss of hair.

DES means drug-eluting stent, explained under Stent.

Diabetes, in full Diabetes mellitus, is a common condition where the glucose in the blood is too high because the body cannot use it correctly. It is a disorder of the carbohydrate metabolism giving excessive thirst, and producing urine with an excess of sugar. Healthy people have no sugar in their urine.

Type 1 diabetes, insulin dependent diabetes, is when the body does not produce insulin because the pancreas cells that make it have been destroyed. It develops over a few weeks; and is treated by insulin injections, regular exercise, and diet. In the UK there are about 350 000 Type 1 diabetics (2002 figure).

Type 2 diabetes, non-insulin dependent diabetes, is when the body produces some insulin but not enough. It develops slowly; is less severe than Type 1; and is treated by diet, exercise, tablets, and/or insulin. In the UK there are about 1 million Type 2 diabetics (2002 figure). Until recently Type 2 diabetes was found only in people over 40, or among younger people with a genetic risk such as Asians.

Diabetes produces increased thirst, abnormally large amounts of urine, tiredness, weight loss, itching, and/or blurred vision.

Diabetics have a higher risk of developing heart disease, stroke, high blood pressure, circulation problems, and/or damage to nerves, kidneys and eyes. The risks are very high for those who are overweight, smoke, and/or are not physically active. See Glucose, and Insulin.

If untreated, diabetes may lead to heart disease, stroke, and/or kidney disease.

A urine test detects glucose in the urine. There should be none. If diagnosed early, Type 2 diabetes can be reversed through lifestyle changes, and/or controlled by drugs and diet.

Treatment for Type 2 diabetes and heart disease. In 2004 researchers and doctors were and still (2010) are uncertain of the best treatment for patients with both Type 2 diabetes and ischemic heart disease IHD – inadequate supply of blood to some heart muscles, usually from obstructed blood flow.

In diabetes our metabolism, the way our bodies use digested food, goes wrong. In healthy people, digestion turns food into glucose – the form of sugar carried in blood. Glucose is the main source of fuel for the body. After digestion, glucose passes into the bloodstream, and is used by body cells for growth and/or energy. For glucose to get into cells, insulin, a hormone produced by the pancreas, must be present.

When healthy people eat, the pancreas produces the right amount of insulin to move glucose from blood into body cells. In diabetics either the pancreas produces too little or no insulin, or the cells do not respond appropriately to it. The body cannot use the glucose. Glucose in the blood increases and is removed in urine.

Diastolic. See Blood pressure. For diastolic heart failure see Heart failure terms.

Diazepam, closely related to lorazepam, is the most widely-used benzodiazeopine drug. Its wide uses include: to relieve tension and nervousness and relax muscles; to help sleep; and to relieve anxiety, alcohol withdrawal, epileptic fits. It can be habit-forming. The effects may reduce with time.

Brand names of diclofenac include: Dialar, Diazemuls, Diazepam Rectubes, Rimapram, Stesolid, Tensium, Valclair, Ativan,.

Side effects are: drowsiness during the daytime, dizziness; and rarely: headaches, blurred vision, forgetfulness, confusion, and a rash.

Diclofenac is an NSAID analgesic with similar properties to paracetamol. It is taken to relieve mild headaches, and pains such as from minor surgery or menstrual pains.

Brand names of diclofenac include: Diclomax SR, Motifene, Rhumalagan, Volraman, Voltarol Pain-Eze.

Side effects are: gastrointestinal disorders; and rarely: headache, dizziness, drowsiness, swollen ankles and/or feet, rash, wheezing, breathlessness, black or bloodstained faeces.

In September 2011 researchers found that for those with an already high risk of heart disease or stroke it may cause problems. If a young woman takes diclofenac, the absolute risk of having a heart attack is raised from the normal 0.1% to 0.14% (which gave the misleading headline 40% increase - the increase in relative risk). Some experts have therefore suggested diclofenac should be made prescription only.

Diet. See separate factsheet on diet. This includes balanced diet, oily fish, poultry, five-a-day. See also oily fish under fatty acids.

The recommendations are aimed at preventing or reducing the risks of heart disease. They do not apply to children under five years old or to people training for sports or who are ill.

Dilate, dilation, means to make or become larger or widened or enlarged.

Dipyridamole is a drug developed in the 1970s as an anti-angina to help people to exercise. More effective drugs for that have been developed since; but it is still prescribed as an antiplatelet. Dipyridamole acts by thinning the blood, reducing the risk of a clot forming eg in an artery – useful for patients who have had a stroke or transient ischaemic attacks, TIAs or have had a heart valve replaced. It is usually given with other drugs such as warfarin or aspirin.

As side effects it may cause stomach upset, nausea, and/or headache. Rarely it may cause diarrhoea, dizziness, fainting, rash, or breathing difficulties. It may interact with anticoagulants and increase their effect – giving increased risk of bleeding. It may also interact with antacids which may reduce its effectiveness. See also under MIBI.

Disability. See Disability under Impairment.

Disease means any poor working of a body function, eg a change from normal caused by an infection, stress, illness or sickness.

Diuretic. Diuretics are drugs that act on the kidneys to turn excess body water into urine. When the urine passes out of the body, this relieves two disorders. The tissues become less swollen from excess water, called oedema; and the heart action improves as it has to pump less blood.

Diuretics are prescribed to help treat hypertension (= high blood pressure), as removing excess water reduces the total volume of blood to be pumped round, reducing the pressure needed. Diuretics are also prescribed to patients whose heart pumping has become weaker than normal, and works as above.

Diuretics are also prescribed to patients with oedema caused by a kidney disorder; cirrhosis of the liver where excess fluid accumulates in the abdominal cavity; and where premenstrual hormone activity may causes fluid retention.

Loop diuretics are fast acting to increase the output of urine for just a few hours. Loop diuretics genetic and brand names:

- Bumetanide, brand name Burinex;

- Furosemide, brand names Froop, Lasuix, Frusol;

- Torasemide.

Thiazides are the commonest diuretics, but can cause potassium deficiency so a potassium supplement is often prescribed as well. See Thiazide. Genetic and brand names:

- bendroflumethiazide; brand names: Aprinox, Neo-NaClex

- Chlortalidone;

- Cyclopenthiazide;

- Hydrochlorothiazide; no brand names as such, but used in various combined drugs.

- Hydroflumethiazide;

- Indapamide; brand names: Natrilix SR, Nindaxa

- Metolazone;

- Xipamide.

Divalent. See divalent under Organic chemistry.

Do not resuscitate. One can make an advance decision and tell relatives.

Doctors and other medics will not resuscitate if any of the following three conditions occur.

1 'Do not resuscitate' requested by the patient and the patient is able to make that decision.

2 A doctor decides it is impossible to resuscitate the patient.

3 A doctor decides they are unlikely to be able to resuscitate satisfactorily, with a satisfactory outcome.

The relatives may request a second opinion. But they cannot override a patient's decision if the patient is able to decide.

The relatives won't / cannot be told of a patient's decision if the patient does not give permission for them to be told - ie patient confidentiality.

Doctor has two meanings.

- a person qualified and licensed to practise medicine and treat patients. From 16 November 2009, the General Medical Council GMC introduced a new scheme for doctors to register and be licensed to treat patients, and in early 2010 they were consulting on revalidation. This was proving unsatisfactory, so in June 2010 the new government extended the consultation and trials for a further year and stopped the rollout.

 Anyone can check a doctor’s registration at (This is not a link) or phone 0161 923 6602, but normally this shouldn’t be needed.

- The other meaning is a person with a doctorate – a person who has after graduating:

- has done research in a specialist field / subject for at least three full-time years or equivalent;

- learnt about and showed ability to apply methods of research;

- has created new knowledge worthy of publication in a research journal;

- written a thesis on what they have done; and

- been examined by a viva (oral discussion & examination) by experts in that field.

 The degree is PhD = Doctor of Philosophy for most branches of science at most universities (DPhil at Oxford); MD = Doctor of Medicine; DD = Doctor of Divinity. A DSc, Doctor of Science, is an honorary degree recognising an outstanding research record over many years.

Donor means a person whose organs may be or are being or have been donated for a transplant to another person. The patient receiving the organ is the recipient.

There are not enough donor hearts to offer a lifeline to all those who need them. In 2004/05, 115 heart transplants were done in the UK; but 15 patients died while waiting for a donor heart. At 31 March 2007, 7,234 patients were listed as actively waiting for a transplant.

In the UK between 1 April 2006 and 31 March 2007:

3,086 organ transplants were carried out, thanks to the generosity of 1,495 donors.

949 lives were saved in the UK through a heart, lung, liver, or combined heart/lungs, liver/kidney, liver/pancreas, or heart/kidney transplant.

2,137 patients received a kidney, pancreas or combined kidney/pancreas transplant.

2,402 people had their sight restored through a cornea transplant.

A record number of non-heartbeating donor kidney transplants took place and accounted for one in seven of all kidney transplants.

164 combined kidney / pancreas transplants took place (representing a 53% increase on 2005-2006).

Living donor kidney transplants are increasing – 461 in 2003-2004, 475 in 2004-2005, 589 in 2005-2006, and 690 in 2006-2007; and now represent more than one in four of all kidney transplants.

Donor register. The Donor Register is a means for individuals to express their wishes to donate organs and tissue for transplantation and give critically ill people the opportunity of a longer and better life. The benefits of transplantation are available for all to see – just go to the Transplant Games, held annually around the UK, and see the new lives that recipients are living.

At any time in the UK about 8,000 patients are waiting for a transplant. Eg in early June 2006 this included 104 UK people including 9 children registered waiting for a heart transplant.

Because of the shortage of donors only about 3000 transplants are done in the UK per year. Each year about 1000 patients die while waiting for a transplant (2006-7 figures, see details below).

About a million more people pledged to help others after their death by registering their wishes on the NHS Organ Donor Register, bringing the total from 13.2 in March 2006 to 14,201,229 at 31 March 2007.

The UK has an opt-in position – ie if a person is willing after their death for their organs to be used for transplants to others they can get that recorded by adding themselves to the Donor Register. This can be done online through the Bristol-based charity Transplants in Mind at If during their lifetime they have not opted in, after their death it is initially assumed that their organs cannot be used – their relatives may be consulted and may give that consent.

For many years some people have been in favour of the alternative, opt-out – where it is assumed that everyone is willing for their organs to be donated after death unless they were to indicate otherwise by opt-out during their lifetime. This would make far more organs available, saving the lives of many who are waiting for a transplant.

Related issues include the following.

● Some people are willing to donate a kidney – which some people can do without affecting their own future health

● Some people want to leave their bodies including most organs for medical research and/or teaching eg for three years after death; but eg their cornea could be transplanted

● How to ensure the accuracy, privacy, and security of centrally held databases while making access widely available quickly to those who need the information immediately after the death

● Preferably people should not have continuously to carry a card or other indicator of their wishes throughout their lives. This is inconvenient, requires effort, and in some situations is impossible or unreasonable.

Dorsal means towards or relating to the back or spine. Opposite of Ventral. Also see Posterior.

Double-blind trial. In a double-blind trial patients who have a particular set of conditions are randomly allocated to one of several alternative treatments. One treatment is a placebo – that is a tablet that has no active ingredient, thus giving a control group.

The aim of the research trial will typically be to investigate a hypothesis that is a proposition.

The term double blind applies because neither the medics nor the patient knows whether that patient is receiving the drug, or which of several drugs at what dose, or a placebo. Usually the trial is randomized, so each patient selected to be included in the trial is randomly allocated to one of the various alternatives. The results after the trial period are then compared to look for statistically significant differences between the alternative groups.

Eg in a trial of prescribing thyroxine for hypothermia and low basal metabolic rate, the team selected all those patients – about 100, who: attended an old people's clinic regularly every six weeks, were aged over 50, had temperature lower than 96F, (35.5C) at 10am, and consented to being in the trial. A drug manufacturer was asked to make packs of 42 tablets of six colours – with some colours having the standard dose of thyroxine and others being placebos. The 100 patients were randomly allocated to the colours.

At a 'first' checkup, called A, each patient had his or her head and shoulders photo taken under standard conditions, and was given 42 coloured tablets to be taken daily. At the next checkup, B, exactly six weeks later, each was again photographed and got another 42 tablets. At the third checkup, C, their photo was again taken.

Any who had a hospital appointment in their 12 weeks or did not complete the whole were excluded, leaving 87. A panel of seven doctors who had never had any contact with any of the patients was assembled. They were shown the photos in a properly randomized order, and each doctor recorded a mark for the wellbeing of the patient as judged solely from the photo.

In the analysis the means and standard deviations of the A photos, the B photos, and the C photos were calculated for each colour. Then for each colour the statistical significances of the differences of B from A, C from B, and C from A were calculated. For three colours the C-A differences were (highly) significant at 1%, and the B-A and C-B differences either significant at 5% or significant at 1%. For the other colours no significant differences occurred. Similar patterns applied to men and women patients separately.

In this research trial even the people doing the statistical analysis did not know which colours were what, nor how many of the colours had thyroxine!

The team then wrote to the drug company, and they replied that those three colours were the ones with thyroxine, and that the others were placebos.

Thus over six to 12 weeks the wellbeing of a patient with low temperature will probably improve if prescribed thyroxine. This research was done in the 1960s.

Drip means the same as intravenous infusion – a slow injection of a fluid into a vein.

Drug. A drug is any substance used as an active chemical in the composition of a medicine.

Inert substances – inactive ingredients that do not have any significant biochemical effect – may be added to create a desired volume, taste, consistency, colour, or other properties.

Each drug has a generic name, brand names for marketing by different companies, a usual recommended dosage or pattern, how soon it takes effect, and how long it remains active. It may have associated advice on diet, storage, and/or missed doses. The drug may produce side effects or adverse affects, may interact with certain other drugs, may need special precautions, and/or may lead to longterm effects so monitoring may be advised.

Before buying medicines over the counter tell your pharmacist what medication you are taking, to avoid accidentally buying a drug that interacts with some drug you are already taking. This is important for medication for indigestion, coughs, colds, headache, sinus problems, or hay fever.

It is often helpful to keep a list of all medication you are currently taking.

Finding drugs in this glossary

See glossary entries for any of: ACE inhibitor, alphablockers, analgesic, anticoagulant, aspirin, aspirin is an NSAID, betablocker, calcium channel blockers, clopidogrel, co-codamol, co-proxamol, glyceryl trinitrate, ibuprofen, ISMO, Medicines – taking and storing, nitrates, non-opioids NSAIDs and non NSAIDs, opioids, paracetamol, potassium channel activator, side effect, slow release under half-life, statin, thyroxine, valsartan, warfarin.

The generic and/or brand names of many drugs occur in the Glossary text – try looking at the links under Brand names, or doing a Find on the name, using the find box at the top.

Drug-eluting stent. See under Stent.

Dyspnoea (or dyspnea) means breathlessness. Exertional dyspnoea means breathlessness on exertion. Nocturnal dyspnoea means night breathlessness. See under Heart failure diagnosis. Compare Apnoea is a temporary inability to breathe.


This information was created and edited by Richard Maddison for the BCPA.
Copyright © 1997-2019 The British Cardiac Patients Association, and/or Richard Maddison.
BCPA Head Office: 15 Abbey Road, Bingham, Nottingham NG13 8EE
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First published in this form 2002, and updated 2005, 2007, 2008, 2011, 2012, 2013, 2017.
All rights reserved. No part of this work may be reproduced, stored in a retrieval system or transmitted, in any form or by any means, without written permission from the BCPA Head Office.

We give permission for copies to be stored and made within the BCPA and any UK hospital; and these hospitals may give printed but not electronic copies to patients provided the source and copyright is acknowledged on the copies - eg include the page footer.

Authors, sources and acknowledgements

The main sources are BCPA Journal published articles, other information from authors, and publicly available documents and websites. In many cases the journal articles give sources and further information than the Glossary entries.

Parts of the wordings under ECG and Echocardiogram are adapted with permission from BUPA's health information resources, available at

We hope we have thanked everyone.

Richard Maddison

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