A B C D E F G H I J K L M N O P Q R S T U V W X Y Z


T

TACHYCARDIA Tachycardia is an increase of the heart rate above the normal level. Among its many possible causes are arrhythmias, illness, exercise, stress, or excitement.

TELEMETRY Telemetry is a method of placing a patient on an electrocardiogram (EKG) monitor without having wires limiting activity. The EKGs are transmitted via radio waves to a central monitoring point. Patients can therefore walk around while still being monitored.

THALLIUM STRESS TEST A thallium stress test may be done at rest, or follow the same procedure as a graded exercise test, with an intravenous injection of a low dose of radioactive material at peak exercise. This is immediately followed by a scan of the heart to visualize areas of the heart that do not receive sufficient blood supply. A comparative scan will be done four hours later to note any changes at rest.

THROMBOLYTIC AGENTS Thrombolytic agents are intravenous drugs which are administered during a heart attack. These drugs are intended to break up a thrombus, thereby allowing blood to reach the heart muscle.

THROMBOLYTIC THERAPY In thrombolytic therapy, medication is given intravenously to dissolve the blood clot causing the heart attack. Once the blood clot is dissolved, blood flow can be restored to the affected area of the heart. Activase (t-PA) or Streptokinase are the most common medications used for dissolving a blood clot.

THROMBUS A thrombus is when a blood clot is formed in a diseased blood vessel. When a thrombus blocks the blood supply to an organ it can cause death to all or part of that organ. A thrombus in the heart (coronary thrombosis) can cause a heart attack (cardiac arrest), while a thrombus in the brain can cause a stroke. (For thrombus in a vein see phlebothrombosis.) If a thrombus breaks free and joins the bloodstream it is called an embolism.

TRANSESOPHAGEAL ECHOCARDIOGRAM A transesophageal echocardiogram is the same as a standard echocardiogram, except a miniaturized transducer (the probe) is passed down the esophagus by means of a flexible scope to visualize the heart. Sound waves are used to image/take pictures of vital structures such as the heart and aorta.

TRICUSPID VALVE The tricuspid valve separates the right atrium from the right ventricle. The tricuspid valve is comprised of three leaflets that, when open, permit blood to flow in only one direction - from the right atrium into the right ventricle.

TRIGLYCERIDE Triglyceride is a type of fat made up of glycerol and three fatty-acid molecules. The body makes triglycerides from the products of digestion of dietary fat. Fat is then stored in the body as triglycerides.

V

VAGUS NERVE The vagus nerves are paired nerves on each side of the body which carry parasympathetic impulses to the heart and other body organs. These impulses slow the heart when it is beating too quickly.

VALVULOPLASTY Valvuloplasty is a procedure usually performed to treat a stenotic valve. During this procedure the surgeon opens up the narrowed valve. This can be done with an incision, while on cardiopulmonary bypass, or in certain cases by closed heart techniques. In a balloon valvuloplasty, a small deflated balloon is guided into a valve opening via a catheter (hollow tube). Once inside the valve opening, the balloon is inflated. These procedures help to widen the valve, thereby permitting an increased blood flow.

VEIN A vein is a blood vessel that carries oxygen-poor blood to the heart. (The only exception is the pulmonary vein.) Blood from the veins enter the right atrium of the heart through the vena cava.

VENA CAVA (pl. venae cavae) The superior and the inferior vena cava both deliver oxygen-poor blood into the right atrium of the heart. The superior vena cava draws blood from above the diaphragm, while the inferior vena cava draws blood from below.

VENTRICLE The right and left ventricles are the two muscular lower chambers of the heart. The right ventricle pumps oxygen-poor blood received from the right atrium out to the lungs through the pulmonary artery. The left ventricle pumps oxygen-rich blood received from the left atrium out to the body through the aorta.