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At a glance: a definition of terms

Allotransplantation: The transfer of cells, tissues, and/or whole organs from one individual to another within the same species.

Anencephaly: Absence of the higher brain centers; 50 percent of such infants are stillborn; 45 percent die shortly after birth. Approximately 5 percent may survive for months or years in a vegetative state.

Antigen: Any material that can induce or bring about the action of an immune response, the end result of which usually is the destruction of the antigen by that response.

Brain death: Absence of brain and brain stem activity indicating death of all brain tissue. Diagnosis of brain death may be made by bedside examination and confirmed by electroencephalography (EEG, brain wave study). The diagnosis requires observations by two or more physicians. In the field of transplantation, this term is usually employed to describe a cadaveric donor in which the heart is beating, but there are no measurable brain waves or deep reflexes. It has been declared as a condition incompatible with continued life and results in eventual stoppage of the heart and all other life function.

Cyclosporine: A drug derived from a fungus found in soil that is a powerful and selective immune system suppressant.

Donor: In transplantation, this is the individual (animal or human) from whom tissues or organs are derived for the benefit of a potential recipient in need of those tissues or organs for normal health and/or survival.

Ductus arteriosus: During life in the uterus, blood circulation between the two halves of the heart mix through a connection between the aorta and the pulmonary artery. This connection normally closes shortly after birth. In infants with hypoplastic left-heart syndrome, the presence of this "open" ductus arteriosus permits blood exiting the heart to circulate the body. Closure of the ductus arteriosus results in death of these infants.

EKG: A graphic tracing of the electrical potential caused by the excitation of the heart muscle which is detected at the body surface.

Endomyocardial biopsy: The sampling of tissue from the inside walls of the heart. This task is accomplished by threading a long, fine tube (catheter) through a vein in the patient's neck/arm into the chambers of the heart where a sample is taken by a small biting action at the end of the catheter.

Genetic disparity: The differences in genetic material found in the cells of two non-identical individuals. Cells, tissues, and/or organs transplanted between two non-identical individuals will reject (without medication) because of the genetic disparity found between them. Tissues transplanted between identical twins will not be rejected because they are genetically identical.

Graft: An implant or transplant of any tissue or organ.

HLA: Abbreviation for human lymphocyte

Hyperacute rejection: The immediate killing (as soon as blood flows through vessels) of a transplanted organ, seen to occur in a patient who has preformed antibodies to the donor flowing in his or her blood stream.

Hypoplastic left-heart syndrome: Complete or partial absence of structures of the left side of the heart.

Immaturity of newborn response: At the time of birth, the immune system of newborn humans and animals is not capable of responding as effectively as it will in the adult stage. Although there is an immune system in newborns which is capable of responding to foreign material, it is significantly weaker than it will be when the infant is older.

Immunosuppression: The act of inhibiting the reactivity of the immune system against foreign material.

Ischemic times: The time outside the chest when the heart is not beating or being supplied with oxygen.

Rejection: The destruction of a graft by the immune system of the recipient. Destruction can be brought about by cells (lymphocytes) or antibodies or both. Destruction may be reversible and/or irreversible, and can occur at any time after transplantation. The earliest rejection can occur at the moment is which blood flow is restored to the donor organ.

Xenotransplantation: The transfer of cells, tissues, and/or an organ from an individual of one specie to an individual of another specie.

Loma Linda University Medical Center Heart Transplant: 11234 Anderson Street, P.O. Box 2000, Loma Linda, CA 92354
Telephone: (909) 558-4201