Q-Z

Radial artery access – Using the radial artery in the wrist as the entry point for the catheter in an angioplasty or stent procedure. Also called transradial access, the transradial approach, or transradial angioplasty.

Radionuclide imaging – A test in which a harmless radioactive substance is injected into the bloodstream to show information about blood flow through the arteries. Damaged or dead heart muscle can often be identified, as can serious narrowing in an artery.

Radionuclide studies – Any of the diagnostic tests in which a small amount of radioactive material is injected into the bloodstream. The material makes it possible for a special camera to take pictures of the heart.

Radionuclide ventriculography – A diagnostic test used to determine the size and shape of the heart’s pumping chambers (the ventricles).

Regurgitation – Backward flow of blood through a defective heart valve.

Renal – Pertains to the kidneys.

Restenosis– The re-closing or re-narrowing of an artery after an interventional procedure such as angioplasty or stent placement.

Revascularization – A procedure to restore blood flow to the tissues. Coronary artery bypass surgery is an example of a revascularization procedure.

Rheumatic fever – A disease, usually occurring in childhood, that may follow a streptococcal infection. Symptoms may include fever, sore or swollen joints, skin rash, involuntary muscle twitching, and development of nodules under the skin. If the infection involves the heart, scars may form on heart valves, and the heart’s outer lining may be damaged.

Rheumatic heart disease – A disease of the heart (mainly affecting the heart valves) caused by rheumatic fever.

Right ventricular assist device (RVAD) – A mechanical device that can be placed outside the body or implanted inside the body. An RVAD does not replace the heart—it “assists” or “helps” it pump oxygen-poor blood from the right ventricle to the lungs.

Risk factor – An element or condition involving a certain hazard or danger. When referring to heart and blood vessels, a risk factor is associated with an increased chance of developing cardiovascular disease, including stroke.

Rubella – Commonly known as German measles.

Saccular aneurysm – A round aneurysm that bulges out from an artery; involves only part of the circumference (outside wall) of the artery.

Sarcoidosis – An inflammatory disease that starts as tiny, grain-like lumps called granulomas, which most often appear in your lungs or lymph nodes. The granulomas can clump together and form larger lumps that attack other organs. Sarcoidosis often affects your skin, eyes, or liver, but it can lead to heart problems, such as irregular heartbeats (arrhythmias) or restrictive cardiomyopathy.

Saturated fat – Type of fat found in foods of animal origin and a few of vegetable origin; they are usually solid at room temperature. Abundant in meat and dairy products, saturated fat tends to increase LDL cholesterol levels, and it may raise the risk of certain types of cancer.

Second-degree heart block – Impulses traveling through the heart’s upper chambers (the atria) are delayed in the area between the upper and lower chambers (the AV node) and fail to make the ventricles beat at the right moment.

Septal defect – A hole in the wall of the heart separating the atria or in the wall of the heart separating the ventricles.

Septum – The muscular wall dividing a chamber on the left side of the heart from the chamber on the right.

Sheath – A catheter-like tube that is placed inside a patient’s vessel during an interventional procedure to help the doctor with insertion and proper placement of the actual catheter. Also called an introducer sheath.

Shock – A condition in which body function is impaired because the volume of fluid circulating through the body is insufficient to maintain normal metabolism. This may be caused by blood loss or by a disturbance in the function of the circulatory system.

Shunt – A connector that allows blood to flow between two locations.

Sick sinus syndrome – The failure of the sinus node to regulate the heart’s rhythm.

Silent ischemia – Episodes of cardiac ischemia that are not accompanied by chest pain.

Sinus (SA) node – The “natural” pacemaker of the heart. The node is a group of specialized cells in the top of the right atrium which produces the electrical impulses that travel down to eventually reach the ventricular muscle, causing the heart to contract.

Sodium – A mineral essential to life found in nearly all plant and animal tissue. Table salt (sodium chloride) is nearly half sodium.

Sphygmomanometer – An instrument used to measure blood pressure.

Stem cells – Special cells in the body that are able to transform into other cells. It is possible for stem cells to transform into heart cells, nerve cells, or other cells of the body, possibly helping to improve the function of failing organs, including the heart.

STEMI – ST-segment-elevation myocardial infarction. The more severe form of the 2 types of heart attack. See also NSTEMI. A STEMI produces a characteristic elevation in the ST segment on an electrocardiogram.

Stent – A device made of expandable, metal mesh that is placed (by using a balloon catheter) at the site of a narrowing artery. The stent is then expanded and left in place to keep the artery open.

Stenosis – The narrowing or constriction of an opening, such as a blood vessel or heart valve.

Stethoscope – An instrument for listening to sounds within the body.

Stokes-Adams disease – Also called third-degree heart block; a condition that happens when the impulses that pace your heartbeat do not reach the lower chambers of your heart (the ventricles). To make up for this, the ventricles use their own “backup” pacemaker with its slower rate. This rhythm can cause severe dizziness or fainting and can lead to heart failure or death.

Streptococcal infection (“strep” infection) – An infection, usually in the throat, resulting from the presence of streptococcus bacteria.

Streptokinase – A clot-dissolving medicine used to treat heart attack patients.

Sternum – The breastbone.

Stress – Bodily or mental tension resulting from physical, chemical, or emotional factors. Stress can refer to physical exertion as well as mental anxiety.

Stroke – A sudden disruption of blood flow to the brain, either by a clot or a leak in a blood vessel.

Subarachnoid hemorrhage – Bleeding from a blood vessel on the surface of the brain into the space between the brain and the skull.

Subclavian arteries – Two major arteries (right and left) that receive blood from the aortic arch and supply it to the arms.

Sudden death – Death that occurs unexpectedly and instantaneously or shortly after the onset of symptoms. The most common underlying reason for patients dying suddenly is cardiovascular disease, in particular coronary heart disease.

Superior vena cava – The large vein that returns blood from the head and arms to the heart.

Supraventricular tachycardia (SVT) – A regular rapid heart rate (150-250 beats per minute) that is caused by events triggered in areas above the heart’s lower chambers (the ventricles); see also paroxysmal supraventricular tachycardia (PSVT).

Syncope – A temporary, insufficient blood supply to the brain which causes a loss of consciousness. Usually caused by a serious arrhythmia.

Systolic blood pressure – The highest blood pressure measured in the arteries. It occurs when the heart contracts with each heartbeat.

Tachycardia – Accelerated beating of the heart. Paroxysmal tachycardia is a particular form of rapid heart action, occurring in seizures that may last from a few seconds to several days.

Tachypnea – Rapid breathing.

Tamponade – Also called cardiac tamponade. A condition in which the heart is compressed or constricted because of a large amount of fluid or blood in the space between the heart muscle and the sac that surrounds the heart (the pericardium).

Thallium-201 stress test – An x-ray study that follows the path of radioactive potassium carried by the blood into heart muscle. Damaged or dead muscle can be defined, as can the extent of narrowing in an artery.

Third-degree heart block – A serious condition also called Stokes-Adams disease; impulses from the heart’s upper chambers (the atria) are completely blocked from reaching the heart’s lower chambers (the ventricles). To make up for this, the ventricles use their own “backup” pacemaker with its slower rate.

Thrombolysis – The breaking up of a blood clot.

Thrombosis – A blood clot that forms inside the blood vessel or cavity of the heart.

Thrombolytic therapy – Intravenous or intra-arterial medicines that are used to dissolve blood clots in an artery.

Thrombus – A blood clot.

Thyroid – A gland located in the front of the neck, just below the voice box.

Tissue plasminogen activator (tPA) – A clot-dissolving medicine that is used to treat heart attack and stroke patients.

Trans fat – Created when hydrogen is forced through an ordinary vegetable oil (hydrogenation), converting some polyunsaturates to monounsaturates, and some monounsaturates to saturates. Trans fat, like saturated fat, tends to raise LDL cholesterol levels, and, unlike saturated fat, trans fat also lowers HDL cholesterol levels.

Transcatheter aortic valve implantation (TAVI) – A minimally invasive procedure to repair a damaged or diseased aortic valve. A catheter is inserted into an artery in the groin and threaded to the heart. A balloon at the end of the catheter, with a replacement valve folded around it, delivers the new valve to take the place of the old. Also called TAVR (Transcatheter aortic valve replacement).

Transcatheter intervention – Any of the noninvasive procedures usually performed in the cardiac catheterization laboratory. Angioplasty is an example of a transcatheter intervention. Also called a percutaneous coronary intervention (PCI).

Transesophageal echocardiography – A diagnostic test that analyzes sound waves bounced off the heart. The sound waves are sent through a tube-like device inserted in the mouth and passed down the esophagus (food pipe), which ends near the heart. This technique is useful in studying patients whose heart and vessels, for various reasons, are difficult to assess with standard echocardiography.

Transient ischemic attack (TIA) – A stroke-like event that lasts only for a short time and is caused by a temporarily blocked blood vessel.

Transplantation – Replacing a failing organ with a healthy one from a donor.

Tricuspid valve – The structure that controls blood flow from the heart’s upper right chamber (the right atrium) into the lower right chamber (the right ventricle).

Triglyceride – The most common fatty substance found in the blood; normally stored as an energy source in fat tissue. High triglyceride levels may thicken the blood and make a person more susceptible to clot formation. High triglyceride levels tend to accompany high cholesterol levels and other risk factors for heart disease, such as obesity.

Ultrasound – High-frequency sound vibrations, which cannot be heard by the human ear, used in medical diagnosis.

Valve replacement – An operation to replace a heart valve that is either blocking normal blood flow or causing blood to leak backward into the heart (regurgitation).

Valvuloplasty – Reshaping of a heart valve with surgical or catheter techniques.

Varicose vein – Any vein that is abnormally dilated (widened).

Vascular – Pertains to the blood vessels.

Vasodilators – Any medicine that dilates (widens) the arteries.

Vasopressors – Any medicine that elevates blood pressure.

Vein – Any one of a series of blood vessels of the vascular system that carries blood from various parts of the body back to the heart, returning oxygen-poor blood to the heart.

Ventricle (right and left) – One of the two lower chambers of the heart.

Ventricular Assist Device (VAD) – A mechanical pump that helps the ventricles pump blood, easing the workload of the heart in patients with heart failure.

Ventricular fibrillation – A condition in which the ventricles contract in a rapid, unsynchronized fashion. When fibrillation occurs, the ventricles cannot pump blood throughout the body.

Ventricular tachycardia – An arrhythmia (abnormal heartbeat) in the ventricle characterized by a very fast heartbeat.

Vertigo – A feeling of dizziness or spinning.

Wolff-Parkinson-White syndrome – A condition in which an extra electrical pathway connects the atria (two upper chambers) and the ventricles (two lower chambers). It may cause a rapid heartbeat.

X-ray – Form of radiation used to create a picture of internal body structures on film.