Glossary Of Terms - P

Pacemaker Paced beat Pain Chronic pain Palliative Palpitation
Pancreas Paracetamol Patent Patient Advice & Liaison Service PALS Peptic ulcers Percutaneous coronary intervention
Pharmacist Pharmacology Phenol Phenobarbitone Physician Physiological
Pins and needles Pituitary gland Placebo Plaque Plasma Platelet
Pleura Polymyalgia Polyphenol Polyunsaturated fat Potassium channel activators Pre-admission clinic
Prescription Prevention Primary Percutaneous Coronary Intervention PPCI Primary prevention Prophylactic Prostaglandins
Proteins Protoplasm Psychological Public Access Defibrillator Pulmonary artery Pulmonary embolism
Pulmonary vein Pulse Pulses as food

PA = Pulmonary artery. PAP = pulmonary artery pressure.

PAC = Pre-admission clinic, ie an outpatient appointment before being admitted as an in-patient.

Paced beat is a heartbeat initiated by a pacemaker.

Pacemaker. A pacemaker is a system with a pulse generator and one or more electrode leads for electric impulses to stimulate the heart to contract and produce a heartbeat. A permanent pacemaker is inserted under the patient’s skin just above the breast tissue. When the heart needs a signal the pacemaker sends electrical impulses along an electrode lead to stimulate the heart to contract and produce a heartbeat.

See separate factsheet on Pacemaker.

PAD See Public Access Defibrillator under Automatic external defibrillator.

Pain is a sensation of hurting or discomfort resulting from illness, injury, heat, an allergic reaction, or something being wrong in some part of the body. It forms part of the body's warning system intended to prevent further discomfort or injury, and generally to alert the person to the need to do something about it.

Pain is important since otherwise parts of our bodies could be damaged or injured without one being aware of it. The pain signals start eg at the skin and are transmitted through nerves and the spinal cord to the brain, where the brain cells interpret the pain. If the signals did not reach the brain then no pain would be felt. Angina is an example.

Chronic pain means longterm, continually recurring, intractable pain – difficult to deal with, prevent or influence. Such pain needs analgesics or other treatments – such as a TENS machine or even permanently stopping signals from reaching the brain.

The body has its own natural pain-control mechanism that releases its own pain easers called beta endomorphins.

Patients who have had heart operations for example get pains, so need appropriate treatments to manage the pains.

For pain-relieving drugs see eg analgesic, co-proxamol, paracetamol under Analgesic.

Some medics ask a patient to describe his or her pain using words such as sharp, dull, …

An alternative is to ask him or her to say how severe the pain feels on a scale from 0 to 10: with 0 for no pain, 10 for the worst pain he or she ever had or could imagine, and where 4 or more corresponds to wanting some pain reliever or treatment.

A pain may also be continuous – all the time, continual – recurring frequently but not quite all the time, intermittent – on and off, and/or varying in intensity, duration and/or frequency.

A referred pain feels to the patient as though it is at a particular place in their body, but the cause may be somewhere else. Pain in an arm or the neck from angina is an example.

Palliative means relieving the sypmtoms of a medical condition, eg looking after the patient - by care, nursing, treatment and drugs that relieve pain. Palliative care is all the treatment that is not directly curing the condition, eg an operation is not part of palliative care.

Palpitation is a feeling resulting from an erratic heartbeat, often felt in the chest or stomach. See under Atrial fibrillation.

PALS See Patient Advice & Liaison Service.

Pancreas. The pancreas is a large organ on the left behind the stomach at about waist level. It secretes insulin into the bloodstream, and pancreatic juice that goes into the duodenum. Pancreatic juice contains enzymes to aid digestion.

Paracetamol is a non-opioid analgesic (= pain reliever), and not an NSAID.

Paracetamol works by reducing the production of chemicals called prostaglandins in the brain. It does not affect the production of prostaglandins in the rest of the body, so does not reduce inflammation though it may reduce fever. So it can be used for aches and pains including headaches, joint pains, and other pains. It is safe when taken correctly, it does not irritate the stomach, and allergic reactions are rare; so it is used widely. The prostatins are produced as part of the body's response to injury or illness, causing nerves to send feelings of pain to the brain. Paracetamol may block the actions of COX-2 - explained under NSAID; and may release seratonin, which may reduce any feeling of stress.

Any overdose can cause severe liver and/or kidney damage, which can be fatal. Paracetamol is available without prescription, but pharmacies take care when it is being purchased, as care must be taken not to exceed the safe dose of paracetamol. If anyone takes more than that maximum as below take them to A&E without delay.

On average UK adults take about 100 paracetamol tablets per year.
For adults the safe dose is two 500mg paracetamol tablets not less than 6 hours since the previous such; and not more than 4 such sets of two tablets in any 24 hours. For children under 12 lower doses are specified as below. In detail, paracetamol tablets can be taken by adults and those over 12 at the rate of (one or) two tablets every six hours or one every three hours. But they must never be at less than that interval, as any overdose of paracetamol is dangerous, as above. Thus the maximum safe dose is 8 tablets, 4g, in 24 hours. Generally people should not take paracetamol for more than three days unless instructed by a doctor.
For children from age 6 to under 12 the maximum dose every six hours (four times per day) is half a 500mg tablet for a 6-year old, and one 500mg tablet for a child nearly 12. Children under 6 should not be given paracetamol.

See also under ibuprofen, which can be taken while taking paracetamol, as they do not interact. Take care, as the ibuprofen interval is one tablet every four hours or two every eight; whereas the paracetamol is one every three hours or two every six - so they are then not being taken at the same times.

Brand names of paracetamol include: Alvedon, Calpol, Disprol, hedex, Panadol, Panaleve, and others; including some junior brands for children. They are also in the following brand combination drugs: Anadin extra, Migraleve, Panadeine, Paradote, Tylex, and others.

Paroxysmal atrial tachycardia PAT is a too-rapid but regular heartbeat originating in an atrium and caused by anomalies in the AV node, so electrical impulses that control heart muscles do not get correctly delayed by the AV node. The heart muscles and valves may be normal.

Paroxysmal atrial fibrillation comes and goes, and each episode usually stops within 48 hours to a week maybe stopping without any treatment.

Passive smoking. See Passive smoking under Smoking.

Patella is the small bone in the front of the knee joint. Also called kneecap.

Patent (applied to arteries & veins) means not obstructed, open.

Patient is a person receiving medical treatment or care.

Patient Advice and Liaison Service, PALS, is a hospital service that provides confidential advice, help and support to patients and their families to sort out any concerns or queries. If you have some problem or something seems to be wrong, they are people to talk to.

Pensions. See under life expectancy and/or insurance.

Pernicious anaemia See Pernicious anaemia under Anaemia.

PCI see Percutaneous coronary intervention.

Penicillamine is a chelating agent.

Peptic ulcers are lesions in the stomach lining. Lesion has two meanings.

1 It is an injury, eg a wound.

2 It is a structure change that results from disease or injury.

Peptide see peptide and peptide bond, both under organic chemistry, and polypeptide.

Percutaneous coronary intervention, PCI, is an operation going through the skin to access and do something to the heart. Percutaneous means through the skin – eg the absorption of an ointment; or surgery using an angioplasty catheter. Intervention implies using a decisive role or action to change something.

Pericardial disease is a disease of the sac surrounding the heart.

Perindopril. See under Angiotensin converting enzyme inhibitors.

Persantin is a brand name for dipyridamole.

pH stands for potential of hydrogen, which is a measure of how acid or alkaline a liquid is. Pure water has a pH value of 7; acids are less than 7; and alkalines are more than 7.

Pharmacist is an appropriate registered scientist (chemist) concerned with the preparation and dispensing of drugs.

Pharmacology is the science of the biochemistry and use of drugs.

Phenol. A phenol is a compound containing a benzene ring.

A benzene ring is a hexagonal (six sides and six vertices) compound of bonded carbon atoms in a benzene molecule or its derivatives.

Benzene has the formula C6H6. It is a colourless aromatic liquid used: in the manufacture of phenols, as a solvent for fats & resins, and as an insecticide.

Eg phenobarbitone is a phenol, with formula C12H12N2O3, a derivative of barbituric acid. It is a crystalline barbiturate, used as a sedative for treating insomnia and epilepsy; and as a hypnotic, and/or as an anticonvulsant.

A polyphenol is a compound with many phenols, ie with many benzene rings. Polyphenols are beneficial chemicals that help stave off heart disease and cancers. poly- means many.

Physical and/or psychological dependence. See dependence.

Physician is a doctor who treats patients but is not a surgeon – ie doesn’t do surgical operations.

Physiological has two meanings:

- relating to physiology – the biology of living organisms and of their parts; and/or

- in accordance with the normal function of a living organism.

Pins and needles is a tingling feeling as circulation starts again to that part of the body – eg arm, hand, leg, or foot. The blood flow may have stopped because of pressure on an artery, including sitting in the same position for a long time.

Pituitary gland is a gland at the base of the brain. It regulates growth, and sexual and reproductive development. It also stimulates other endocrine glands.

Placebo. A placebo is a medicine, tablet or treatment that has no active ingredient, typically given to a control group in a trial of a drug, so each patient does not know what he or she is receiving.

Also, it means a medicine given to a patient who insists on receiving a treatment, and where the medic or first aider thinks the patient might benefit by the psychological deception and thinks no medicine is needed.

Plaque is a deposit of fatty substances on the inside of an artery wall.

Plaques may become unstable and rupture or breakup, causing damage to the blood vessel wall. The body responds to the breakup by making platelets clump together to producing a clot, a thrombus, and this may cause a partial or complete blockage.

Plasma is a constituent of blood. Plasma is the clear or yellowish fluid in which corpuscles and cells are suspended; including water, dissolved proteins, salts, sugars, fats, minerals, and vitamins.

Platelet. Platelets are small disc-shaped blood structures that are involved in blood clotting. They stick together to form the clot. See Thrombosis and antiplatelet drug.

Plavix. A brand name for clopidogrel.

Pleura are the membranes that cover the lungs and linings of the chest cavity.

PMR = Polymyalgia rheumatica. See Polymyalgia.

poly- means many or much, more than one, from Greek.

Polymyalgia is an inflammatory condition that gives pain in many muscles, with unknown cause. The pains are most often in the shoulders, upper arms, buttocks and thighs. Many patients with this first complain of shoulder pain to their doctor. However, it can also be any or all of back of legs, thighs, buttocks, pelvis, abdomen, chest, arms, shoulders, and/or neck. It causes reduced or limited movements. This is somewhat like for example when at the start of a school term after doing little exercise during the holidays if one did some strenuous exercise one might feel stiff the next day or two and perhaps unable to move limbs fully. It can be worse in the mornings - eg difficulty sitting up and getting out of bed, washing one's face, cleaning teeth, getting dressed and brushing hair; and gradually reduce during the day. It may become difficult to lift a fork or spoon to one's mouth. Many patients feel very tired, feverish, unwell, and/or depressed. Some have reduced appetite and lose weight.

White blood cells attacking the lining of joints cause the inflammation. It may also be caused by viruses, but this is not certain. See myalgia. Also called Polymyalgia rheumatica (PMR). The discomfort may begin on one side, but it soon becomes bilateral.

Women are twice as likely as men to get polymyalgia. It usually affects adults over 50, with the peak ages of such patients being about 70-80. Curiously it is more common among white people than other ethnic groups.

Blood tests called the erythrocyte sedimentation rate (ESR) test, which measures how fast the patient's red blood cells settle in a test tube; and the C-reactive protein (CRP) test can detect if there is inflammation in your body from various diseases. CRP is produced by the liver in response to an injury or infection and people with polymyalgia rheumatica usually have high levels. If either of these blood tests shows a high level of inflammation, and you have the typical symptoms, then this usually confirms the diagnosis of PMR; but the tests are not very specific.

The treatment for polymyalgia is a course of steroids, usually prednisolone. This usually produces a significant improvement within two or three days. The dose can be reduced after a few days, the situation reviewed, and then the reduced steroids continued for a couple of weeks or perhaps up to a couple of years. See corticosteroids, which includes side effects and the pattern of gradually reducing the dose and why. Subsequent ESR tests are needed to monitor the inflammation and help the doctor decide future doses. The aim is to gradually reduce the dose, and as the dose is reduced the body hopefully will start to increase its production of the appropriate hormones back to normal. The PMR usually stops within at most two years. Unfortunately taking the steroid for a long time may as a side effect cause thinning of bones and lead to osteoporosis. So the patient should have plenty of vitamin D and calcium, eat a healthy balanced diet, and do weight-bearing exercises to strengthen the weak muscles and prevent becoming overweight. Calcium and vitamin D supplementation should be given with corticosteroid therapy in all patients with polymyalgia rheumatica.

NSAIDs such as ibuprofen do not help.

Two patients who have had polymyalgia both said that the symptoms, pain and limited muscle movements, come and go - eg can get better and worse alternately over a few days, months or years. One can be free of symptoms for say several months or a year then the pain and limited movement recurs, needing a further blood test and steroid tablets. One has to have the blood tests before starting the tablets again as the tablets would make the blood test result negative.

Polypeptide is any of a group of relatively short-chain proteins consisting of several amino acids linked by peptide bonds.

Polyphenol. A polyphenol is a compound with many phenols, ie with many benzene rings. Polyphenols are beneficial chemicals that help stave off heart disease and cancers.

Polyunsaturated. See polyunsaturated under Fat.

Positive. A positive test result means a condition is occurring. The opposite is called negative.

Posterior means situated at or towards the back of the body. Opposite of Anterior. Also see Dorsal.

Potassium. See under Salt.

Potassium channel activators are used to treat angina. They relax ie widen both the arteries and veins, reducing the work of the heart. They also relax small arteries in the heart to help improve the blood supply to the heart. This should relieve angina attacks, making them less frequent, and reduce the risk of a heart attack.

The generic name is Nicorandil, brand name Ikorel. It was first introduced in 1994. It is taken as tablets, usually twice daily. The effects start about an hour after taking it and last 12 hours. Store the drug in a closed container in a cool dry place out of reach of children.

Possible side effects of potassium channel blockers include: headache, dizziness on standing up, nausea and/or vomiting, and flushing of the face. Most of these side effects are usually minor if they occur at all, and should pass as your body adjusts to it. If you notice any side effects consult your doctor so that he/she may change your medication if these side effects become intolerable.

Potential of hydrogen pH see potential of hydrogen under organic chemistry.

Pre-admission clinic is an outpatient appointment before being admitted as an in-patient.

Prednisolone is a corticosteroid used as an effective way of treating various illnesses involving inflammation. It reduces the inflammation. See polymyalgia. For polymyalgia it should be taken with or after food and all the tablets to be taken on a particular day should be taken together. Corticosteroids occur naturally in the body, helping to maintain health and wellbeing.

Side effects that may occur soon after starting taking it include mood changes - feeling depressed or 'high'; stomach problems; and/or feeling unwell. After weeks or some months one may have weakness of arms or legs; or develop a rounder face. If you take it for more than three weeks you will be given a blue 'steroid card', which you should show to any doctor, nurse or dentist who treats you. One also needs to keep away from anyone with chicken pox or shingles if one has not previously had chicken pox, as this may affect one severely.

Brand names of prednisolone include: Deltacortril, Deltastab, Minims prednisolone, Predenema, Predfoam, Pred Forte, Predsol.

Prescription is a written form giving details to a pharmacist – from a doctor, dentist or other appropriate medic – of what drug(s) in what quantity, how often, and with what instructions to provide to the patient.

Prescription terms and abbreviations. ac = before food; ad lib = freely; am = morning; bd = twice per day; c = with; cap = capsule; cc = cubic centimetre; ext = for external use; gtt = drops; mcg = micrograms; mg = milligrams; ml = millilitres; MR = medium release; nocte = at night or at bedtime; od = each day; om = each morning; on = each night; pc = after food; pm = evening; po = by mouth; pr = by rectum; prn = as needed; pv = by vagina; qds = four times per day - see below; s = without; SR = slow release; stat = at once; tab = tablet; tds = three times per day - see below; top = apply topically ie to the skin; ud = use as directed; x = times.

Three times per day can be whenever best fits with your sleeping and daily routine, eg starting when you get up eg 6am, 7am or 8am and at about 8 hour intervals after.

Four times per day: assuming one sleeps 11pm to 6am say, this can mean either at 6am, 12 noon, 6pm and 11pm; or can mean waking say 2am and taking at 2am, 8am, 2pm, 8pm.

Prevention. Preventing a disease before it happens is called primary prevention.

Once a patient has a disease he or she and others can try to stop it getting worse, or at least slow down its progress, called secondary prevention.

Primary Angioplasty See PPCI.

Primary Percutaneous Coronary Intervention, PPCI. also known as Primary Angioplasty.

Papworth Hospital opened the Papworth Hospital Heart Attack Centre in 2008. Available 24/7, it covers 999 calls for patients who have a heart attack either at home or in hospital – covering the ambulance catchment areas for tens of miles around. Such patients can be admitted directly to Papworth Hospital Catheter Laboratory at any time of day or night for PPCI.

Ambulance paramedics will assess and decide if treatment is required at Papworth.

Until recently a clot-busting injection known as thrombolysis has been the gold standard treatment for a heart attack. This is given either pre-hospital or in-hospital. The aim is to dissolve the blood clot and restore blood flow. For best outcome the thrombolysis must be ASAP – preferably in the first hour of the onset of chest pain – the golden hour. However:

- 30% of patients are not eligible to receive it

- it does not always work – 20 to 30% of patients given thrombolysis re-block their artery shortly after and have a further heart attack

- it only dissolves the clot and does not remove the plaque; and

- there is risk of bleeding – eg stroke.

Nowadays, 25% of heart attack patients in the UK get PPCI. This procedure removes the clot and treats the narrowing to keep the artery open. With lower risk of renarrowing and/or bleeding, PPCI gives superior outcomes provided it is delivered quickly.

A specially-made tube or catheter is passed up to the coronary artery from the groin or wrist. The clot can be removed by a special device – this is called thrombectomy. A stent may be inserted.

National PPCI coverage would prevent around 500 deaths, around 1,000 further heart attacks, and around 250 strokes each year (relative to the figures in 2007) compared with no PPCI as described here.

Primary prevention means preventing a disease before it happens. Compare Secondary prevention.

Prophylactic is a drug or procedure to prevent disease.

Proposition. A proposition is a proposal or statement made for consideration, particularly a statement that affirms or denies something.

Prostaglandins are chemicals in the body, including the brain. See under non-opioids = NSAIDs and non-NSAIDs, and paracetamol.

Proteins are amino acids (explained under organic chemistry) essential for life, health, and brain function. Meat, fish, dairy products, and some other foods contain proteins of various kinds.

Proteins are any of a group of organic compounds that contain carbon, oxygen and nitrogen, that are of high molecular weight, and that are essential constituents of all living organisms. They have one or more amino acids linked by peptide bonds and are folded into a specific three-dimensional shape that is held together by further chemical bonding.

Some experts believe that your body's mechanisms that signal to the brain that you feel hungry or full are partly or mainly detecting the absence or presence of enough proteins. Feelings of hunger or of having had sufficient food and drink also depend on how full the stomach is and the quantities and types of foods / nutrients in the digestive system.

There are eight essential proteins / amino acids.

Complete proteins supply all eight. Adults in good health will get enough of all of them if they eat / drink two servings daily of meat, fish, eggs, cheese, milk, and/or yoghurt. Here milk means ½ pint = 250ml daily of any of whole, semi-skimmed, or skimmed.

Incomplete proteins only supply some of the eight – eg grains, legumes / green vegetables, nuts, seeds. So to get all eight proteins these need to be combined, and/or possibly with other foods.

Proton. See proton under organic chemistry.

Protoplasm is the living part of a cell.

Psychological has several meanings:

- relating to psychology. Psychology is the science and study of mental processes and related behaviour, including emotional and subtle causes and influences.

- relating to the mind and/or mental activity

- affecting the mind

- having no observable cause – eg arising in the mind, eg her pain may be psychological.

Public Access Defibrillator PAD. See Public Access Defibrillator under Automatic external defibrillator.

PUFA. See polyunsaturated fatty acid under Fat.

Pulmonary means associated with the lungs.

Pulmonary arteries PA are the two arteries that take low-oxygen blood from the right ventricle to the lungs. One goes to each lung.

Pulmonary embolism means a blood clot on the lungs, which can be a cause of death. See Embolus.

Pulmonary oedema means crackles or excess fluid in the lung tissues. See heart failure diagnosis.

Pulmonary valve. See under Valve.

Pulmonary vein. The pulmonary veins take oxygen-rich blood from the lungs to the heart.

Pulmonary vein isolation PVI. Where the pulmonary veins enter the left atrium, a band of muscle cells there may discharge electrically wrongly, causing atrial fibrillation. In PVI the faulty cells are destroyed, preventing the AF.

Pulse. This has two meanings.

1 The number of heartbeats per minute – the Heart rate.

2 To take the pulse means to measure, count, and record it, and perhaps note its strength – whether strong or weak, and whether the rhythm is regular or slightly irregular.

Each heartbeat makes a wave of blood of increased pressure flow along the arteries. This can be felt as a pulse where an artery is close to the skin and above a bone – such as in the slight hollow on the thumb side of the wrist, or at the neck or groin. The pulse should be felt with fingers – not the thumb, since the thumb has a pulse.

Pulse is also the title of a journal for UK doctors, particularly GPs.

Pulses also means foods that are edible seeds that grow in pods. For vegetarians they provide proteins, and are healthy for meat-eaters. Pulses include the whole range of beans, peas and lentils:

- baked beans, runner beans, broad beans, kidney beans, butter beans, soya beans;

- red, green, yellow and brown lentils;

- garden peas, split peas, chickpeas.

Most supermarkets have many varieties of pulses. They need no refrigeration or other preserving techniques – other than having been dried, and they have a fairly long shelf life.


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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