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Heart Transplants and the Use of Pacemakers.

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Heart Transplants and the Use of Pacemakers. A transplant is the replacement of a patient's diseased heart with a normal organ from someone--called a donor--who has died. The donor's organ is completely removed and quickly transported to the patient, where it is reattached to the patient. The first human heart transplant was in December 1967 and they have no become commonplace. About 2300 heart transplants are performed each year in the USA alone. Until 1983 the operation was very problematical due to the high chance of rejection of the donor organ by the patient. The drug cyclosporine was then introduced. It is an immuno-suppressant drug which reduces the body's ability to produce antibodies to attack the donor organ. As a result of that drug the number of patients surviving at least a year after a transplant is 80%. Organ availability is the other factor limiting the number of successful transplants. Governments are trying to increase public awareness of this problem and so increase the availability of organs. ...read more.


Transplants are used to treat the following conditions: * Cardiomyopathy--a weakening of the heart muscle. * Severe coronary artery disease--in which the heart's blood vessels become blocked and the heart muscle is damaged. * Birth defects of the heart. However, even with one of these conditions, the patient must fulfil the criteria of: * Have all other therapies been tried or excluded? * Is the patient likely to die without the transplant? * Is the person in generally good health other than the heart disease? * Can the patient adhere to the lifestyle changes--including complex drug treatments and frequent examinations--required after a transplant? Heart transplants are very risky operations and, even after a succesful operation, life expectancy is not long. The main reasons for this are because the heart is rejected by the patient's immune system. Drugs can be used to suppress this rejection but they have severe side-effects, e.g. ...read more.


Other conditions which require pacemakers include heart block -- in which the heart stops beating altogether for several seconds and tachyarrhythmia (an overly rapid heartbeat). The pacemaker has two parts - a battery-powered generator and the wires that connect it to the heart. The coin sized generator, which has an effective life of seven to 12 years, is implanted just beneath the skin below the collarbone. The leads are threaded into position through veins leading back to the heart. The entire implantation procedure requires only a local anaesthetic, and takes about an hour. The most commonly installed pacing device is a demand pacemaker. It monitors the heart's activity and takes control only when the heart rate falls below a programmed minimum -- usually 60 beats per minute. A more sophisticated type of pacemaker actually monitors a number of physical changes in the body which signal an increase or decrease in activity. If the heart's own pacing system fails to respond properly, these rate-responsive pacemakers slowly raise or lower the heartbeat to the appropriate level -- from 60 to perhaps 150 beats per minute. ...read more.

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