Glossary Of Terms - T

Tachycardia Tea Tear duct Teeth Tennis elbow Therapy
Thiazide Thorax Thrombectomy in PPCI Thrombocytopenia Thyroxine, thyroid gland Tilt test under collapse
Titration Topical Trace elements under minerals Trade name Transcatheter Aortic Valve Implantation TAVI Transcutaneous Electrical Nerve Stimulation TENS
Transducer Trans fatty acid Transient under collapse Transoesophageal echocardiogram Transplant Triglycerides
Troponin Tumour

Tachyarrhythmia is an excessively rapid heartbeat plus arrhythmia.

Tachycardia is an abnormally high heart rate, usually over 100 beats per minute. An overactive thyroid may also cause it. See Supraventricular tachycardia. Compare Bradycardia. See also heart failure diagnosis.

Taking medicines. See Medicines - taking and storing.

TAVI See Transcatheter Aortic Valve Implantation.

tds = three times a day. bd (= bpd) = twice per day. od = once a day, qds = four times. See under Prescription terms.

Tea. Brew tea five minutes.

Leaving tea to infuse in the pot five minutes or more gives 60% more of the polyphenols – beneficial chemicals that help stave off heart disease and cancers – in the blood of male volunteers. Whether or not milk or sugar was added made no difference. The teapot should be stirred immediately after adding the boiling water.

In 2007 Dr Garry Duthie, Professor of Molecular Nutrition at the Rowett Research Institute in Aberdeen, tested the blood of male volunteers who drank black tea or tea with milk that had infused for varying times up to ten minutes.

Those who had tea infused for five minutes had 60% more of the good polyphenols than those who drank tea after one minute of infusion. Longer than five minutes, up to ten, gave no further benefit. Three minutes gave only 30%.

So people who just dunk a tea bag and drink the tea almost immediately are not getting the benefit.

Scientists at Harvard Medical School, Massachusetts, claim that drinking tea can reduce the risk of some cancers, heart disease, strokes, and diabetes. In a study, people who had drunk five or more cups of green or black tea per day had lower risk of heart disease and even had longer life.

Drinking two or more cups of green or black tea daily reduced the risk of skin cancer. This is because both green and black teas are rich in antioxidants, which are known to help fight cancer cells.

The 60 million UK population drank on average 165 million cups per day (in 2007) and are the world's second heaviest tea drinkers – second to the Irish.

Tear duct. Just above and to the outer side of each eye is a small gland called the lacrimal gland, which continuously produces a small amount of tears. When you blink the eyelid spreads the fluid over the eye keeping it correctly moist. The tears drain down small channels on the inner side of the eye into a tear sac, from where they flow down a tear duct into the nose. See also under Antihistamine.

A chapped area of skin alongside the nose may indicate a blocked tear duct, causing tears to flow down the face instead of being drained away. This can be from a narrowing of the upper part of the tear duct, maybe caused by some inflammation; or from an injury. If you have a blocked tear duct the stagnant tears within the tear sac may become infected, which may produce a sticky discharge and/or pain and swelling on the side of the nose. Doctors can diagnose and arrange treatment.

Teeth. The British Dental Health Foundation on 23/12/2004 advised ‘Brush before breakfast’. It helps to prevent the dental erosion that can wear away your teeth.

Also a 2004 survey found that 81% of people were unaware that brushing their teeth after eating acidic food and drink can damage their teeth permanently. Acidic foods and drinks – such as oranges, grapefruit and fruit juices that are often eaten at breakfast time – soften the enamel on teeth. Brushing immediately afterwards wears the enamel away. This can cause dental erosion, which may lead to pain and other troubles.

People should discuss tooth-cleaning techniques with their dentist or hygienist. The techniques we learnt as children may not be the best techniques to use now. It is important that the gums are cleaned as well as the teeth, and that this is done in a way that does not damage them. People’s mouths differ – eg some have softer gums; and different mouths may need and benefit from different techniques. Dentists or hygienists will be able to determine and advise you on what is the best way for you. For example some people have gaps between their teeth that need to be kept clean. Dentures need cleaning as well as teeth, so that they do not become infected.

Teeth and heart disease. Many years ago I read that one should clean one’s teeth to reduce the risk of a heart attack. I didn’t understand why.

One’s mouth contains bacteria – that cannot be avoided. Cleaning teeth at least twice a day for hygiene – say after breakfast and towards bedtime – avoids plaque build-up, and reduces the risks of gum disease and losing teeth. This leads to less dental treatment. Chronic gum disease, known as periodontitis, occurs when plaque that collects around the teeth infects the gums.

Cleaning teeth reduces the risk of getting bacteria from the mouth into the gums and the gums becoming infected. The bacteria may get into the blood, and thus can then cause some heart condition.

TENS machine see Transcutaneous Electrical Nerve Stimulation.

The Lancet is a journal for UK doctors.

Therapy means caring for and/or treating a patient who has a disease, or a mental or social disorder.

Thiazide is a diuretic. It prevents water that has been removed from the blood by the kidneys from being reabsorbed into the blood, so the excess water becomes urine. They are the most frequently prescribed diuretics. As they can cause potassium deficiency they are often prescribed with a potassium supplement. There are about eight brand names, listed under diuretics.

Thorax. This is the part of the body enclosed by the ribs.

Thrombocyte is another name for platelet.

Thrombocytopenia means a shortage of the kind of blood cells that make blood clot.

Thrombosis means the formation or presence of a thrombus, which is a solid lump of platelets forming a clot. It can also informally mean a coronary thrombosis. See Deep vein thrombosis.

A thrombus that has formed at the site of a plaque that is in a coronary artery and that has ruptured can gradually grow until it restricts or even stops the blood flow to the heart muscle beyond, causing a heart attack and/or unstable angina.

Thrombolysis is a clot-busting drug treatment. It means injecting a drug such as alteplase that dissolves blood clots that have already formed. See under stroke.

Thyroxine, thyroid gland. The thyroid gland near the base of the neck produces hormones such as thyroxine that control metabolism and body growth.

Hypothyroidism means deficiency of this natural thyroxine – leading to slow body functions and possibly puffiness of the face. During childhood thyroxine is essential for normal growth and physical and mental development. Hyperthyroidism means too much thyroxine. Hypo- = too little; Hyper- = too much.

Patients who are have thyroid deficiency may be prescribed a drug that supplies thyroxine. See example under double-blind trial. Sometimes the dose has to be increased slowly, eg after 3-4 weeks.  

Particular care is needed when treating patients who have heart problems such as angina.

TIA = Transient ischaemic attack.

Tilt test. See tilt test under Collapse.

Titration is a process in chemistry where a measured quantity of one chemical solution is added a little at a time to a measured quantity of some other solution, and the process continues until a reaction is complete – eg all of one solution has reacted. If the concentration of one solution is known and of the other is unknown, from the measured quantities the experimenter could calculate the concentration of the other.

A related meaning is to increase gradually (say each week, fortnight, or month) the dose of a drug given to a patient until a desired improvement in health occurs.

Tolerance of a drug occurs as the body adapts to and its effects. After a time continuously taking a drug the patient may need larger doses to achieve the same effects. The various mechanisms are not well understood. Tolerance to the side effects may also occur. Indeed the side effects may gradually decrease.

Topical means applied to the skin (or ear, nose for nasal passage, anus, vagina) to affect something at that place on the body.

Toxic reaction is an unpleasant reaction eg to an overdose of a drug. A toxin is a poison, eg the effect of a harmful bacteria.

Trace element. See Trace element under Mineral and element under organic chemistry.

Trachea. See trachea under lung.

Trade name = brand name = name for a particular product manufactured and marketed by a commercial company. Contrast with generic name.

Trans. See trans under Fatty acids.

Transcatheter Aortic Valve Implantation, TAVI is alternative to open surgery for patients with high surgery associated risks.

If your aortic valve is severely diseased, you may require replacement of your valve. However you may be advised that an open heart surgery may carry a risk far too high in your case. In this case and if you have the relevant criteria required, you may be eligible for TAVI as an alternative. With this novel approach introduced in the UK in 2007, it will be possible to replace your aortic valve without requiring a full open heart surgery.

According to the NICE Interventional Procedure guidance (June 2008) and the device manufacturers approval, the procedure is limited to small numbers of patients who were considered to be at high risk for conventional cardiac surgery. These are patients who will have a scoring on the logistic EUROSCORE questionnaire above 20%.

TAVI is an alternative to open heart surgery and is considered as a minimally invasive approach. This heart surgery can be performed using echocardiographic and fluoroscopic guidance for visualization during implantation.

During the procedure a valve (a balloon expandable stent combined with a bovine pericardial bioprosthetic tissue valve) is reduced to size and placed on a delivery catheter. The delivery catheter is then inserted either in the femoral artery through a small incision at the top of the leg (transfemoral approach) or between the ribs through the apex of the heart (transapical approach). Once in the heart, the valve is positioned and deployed across the patient’s diseased aortic valve. After a short stay in hospital, the patient can be discharged home with a prescription of clopidogrel (for 3 months) and aspirin (for life).

See also BCPA Journal index and articles such as the following.
TAVI, RM J175p12
 TAVI - NICE guidance boost for patients needing TAVI, Bernard Prendergast J184p10
 UK TAVI forum, John Macgill; Keith Jackson J176p6 UK TAVI forum, John Macgill; Keith Jackson J176p6
 Aortic stenosis and its treatment, Graham Flaye J183p8-9

Transcutaneous Electrical Nerve Stimulation, TENS, is an electronic device for relief of pain. It is used for the symptomatic relief and management of chronic pain and of post-surgical and post-traumatic acute pain problems. TENS means transmitting small electrical pulses through the skin to the underlying peripheral nerves.

It works in two ways. Its high-frequency continuous mild electrical signals may block the pain signal from travelling along the nerves to the brain. Also, it gives low-frequency short bursts of mild electrical signals that may stimulate the body's own natural pain-control mechanism to release its own pain easers called beta endomorphins.

Its use is solely to suppress the pain mechanism from pain at or near the skin. It will not help cure any injury or illness, nor relieve headache, for example. It should not be used until the cause of a pain has been established and treated.

TENS must not be used by patients with a pacemaker, interferes with ECG; and must not be used near the eyes; nor the neck area where it might interfere with normal signals from the brain to the heart. Safety for use during pregnancy has not been established.

TENS should only be used under the continued supervision of a doctor.

Transducer. See under Ultrasound. A transducer is a probe that emits sound waves and can also detect the echo or reflected sound that comes back – eg reflected back from the surfaces outside and inside the heart.

Transient ischaemic attack, TIA is a mini stroke, temporary loss of blood flow to the brain. Transient loss of consciousness See Collapse Loss of consciousness and consciousness.

Transplant means taking an organ, tissue or part of a body from one place to another place – eg from one person to another person; or from one place in a person's body to another place in that person – as a graft. The term transplant is also used to mean the surgical operation.

Transplants in Mind is a Bristol-based charity promoting organ and tissue donation for transplantation. See Donor.

Traumatic means arising from any injury or wound to the body.

Treadmill test. See Exercise stress test under ECG.

Tricuspid valve. See under valve.

Triglycerides are relatively harmful fatty substances in the blood. Most natural fats and oils contain these. The amount can be measured in a blood test.

A triglyceride is any ester of glycerol and one or more carboxylic acids in which each glycerol molecule has combined with three carboxylic molecules. Most natural fats and oils are triglycerides.

Trivalent. See trivalent under organic chemistry.

Troponin. When a heart attack is suspected, blood tests measure various substances including troponins. Troponins of patients with CHD are also measured. Troponins are released into the blood by damaged muscles, they remain in the blood for several days, and their alternative structures distinguish between cardiac or skeletal muscle origins. So if cardiac troponins are present, the patient has had a heart attack and has heart muscle damage.

Troponins are released into the blood by damaged muscles, they remain in the blood for several days, and their alternative structures distinguish between cardiac or skeletal muscle origins. So if cardiac troponins are present, the patient has had a heart attack and has heart muscle damage.

The Troponin starts to build up about six hours after the heart attack, and a blood sample taken at 12 hours can be tested. As it remains for several days the test can also be done anytime then.

Troponin is a complex of three proteins bound together. It helps control contraction and relaxation of both cardiac (heart) muscles and skeletal (skeleton) muscles (attached to tendons to make body movements). But it is not in smooth muscle (muscle in arteries, veins, and some other parts of the body). Troponin allows the chemical process that causes contraction. The three forms are Troponin-T (which binds to tropomyosin to control contraction), Troponin-I (I = inhibit = prevent), and Troponin-C.

As it is not in smooth muscle the test will only give a positive result if there is heart muscle damage, assuming no other skeletal muscle damage.

A study published in the Singapore Med J 1999 found that Troponin T and I are superior to CKMB (serum creatine kinase mass or activity) and CK (serum creatine kinase) in the identification of patients with acute myocardial infarction AMI. Combining multiple sampling of the percentage of CKMB with single confirmatory troponin testing may provide a cost-effective testing protocol for suspected AMI patients.

A study published in the Journal of Family Practice in 2000 found the following. If the peak troponin T or I level measured at least 6 hours after the onset of chest pain symptoms is in the normal range in a patient with a normal electrocardiogram, it is very unlikely that the patient will die or have a nonfatal MI in the next 30 days (1%). The initial troponin value is not as helpful as the peak value at least 6 hours, usually 12 hours, after the onset of chest pain.

Different hospitals use different ones of the three troponin tests.

Truncus arteriosus See under GUCH.

Tumour. A tumour is any abnormal swelling or a mass of tissue formed by a new growth of cells, normally independent of the surrounding structures. Oncology is the medicine and study of tumours.


This information was created and edited by Richard Maddison for the BCPA.
Copyright © 1997-2019 The British Cardiac Patients Association, and/or Richard Maddison.
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First published in this form 2002, and updated 2005, 2007, 2008, 2011, 2012, 2013, 2017.
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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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