Pacemakers
When there are problems with regularity of heartbeat and artifical pacemaker can be used to gain control over the electrical activity of the heart. A pacemaker has two basic components, a pluse generator containing a power sources and one or two pacing leads, each with an electrode on its tip.
Pacemaker can be temporary or permanent. When long term control of the heart is required, a permanent pacemaker is implanted under the skin. The two most common modes of pacing are :
Demand: this detects the heart’s own rhythms and simulates depolarization of the heart muscle, and therefore contraction, as necessary.
Fixed rate: this fires at a predetermined rate irrespective of the heart’s own activity.
Heart transplant suragery
In case of heart disease where all other treatments are inadequate or inappropriate, a heart transplant may be advised. The first heart transplant was carried out in 1967 in south Africa. At first survival rates were low but great resulted in the majority of transplant patients surviving more than five years. The operation itself is relatively simple, with life being sustained by a heart-lung machine during the opereation. The difficult task is caring for the patients afterward, and few institutions are equipped to do this. Although a relative common procedure, demand greatly exceeds the supply of donor hearts. Attempts to develop artificial hearts have not been successful. The last proposal to meet the demand is to use heart from pigs which have been genetically engineered to avoid the potential rejection problems. This may not only raises animal right issues but the possibility of transferring disease from one species to another. This is serious concern, especially in the light of the transfer of BSE to humans from beef. Other ethical issues are raised by transplant surgery, particularly heart transplants. Choices have to be made about who to treat when there is a scarcity of organs. Should smokers be as entitled to treatment as non-smokers, for example? The high cost of transplant surgery also raises the question of how limited resources are best allocated within the National Health Service.
Pacemaker can be temporary or permanent. When long term control of the heart is required, a permanent pacemaker is implanted under the skin. The two most common modes of pacing are :
Demand: this detects the heart’s own rhythms and simulates depolarization of the heart muscle, and therefore contraction, as necessary.
Fixed rate: this fires at a predetermined rate irrespective of the heart’s own activity.
Heart transplant surageryIn case of heart disease where all other treatments are inadequate or inappropriate, a heart transplant may be advised. The first heart transplant was carried out in 1967 in south Africa. At first survival rates were low but great resulted in the majority of transplant patients surviving more than five years. The operation itself is relatively simple, with life being sustained by a heart-lung machine during the opereation. The difficult task is caring for the patients afterward, and few institutions are equipped to do this. Although a relative common procedure, demand greatly exceeds the supply of donor hearts. Attempts to develop artificial hearts have not been successful. The last proposal to meet the demand is to use heart from pigs which have been genetically engineered to avoid the potential rejection problems. This may not only raises animal right issues but the possibility of transferring disease from one species to another. This is serious concern, especially in the light of the transfer of BSE to humans from beef. Other ethical issues are raised by transplant surgery, particularly heart transplants. Choices have to be made about who to treat when there is a scarcity of organs. Should smokers be as entitled to treatment as non-smokers, for example? The high cost of transplant surgery also raises the question of how limited resources are best allocated within the National Health Service.
Comments (0)
Post a Comment