Cardiac Pacemakers Essays (2606 words) - Cardiac Arrhythmia

Cardiac Pacemakers The heart is bestowed with a specialized system that automatically generates rhythmic control via the sinus node, located in the superior lateral wall of the right atrium near the opening of the superior vena cava. The specialized pacemaker cells dictate control of the rest of the heart through regular electrical impulses that propagate from the right atria to the lower ventricles. The rapid conduction of these impulses cause the muscle cells of the atria to contract and squeeze blood into the ventricles, which contract and force blood into the aorta and pulmonary arteries. Abnormalities of the heart rhythm, called arrhythmias, can disrupt this normal cardiac control making it necessary to use some artificial means to regulate the rhythm of the heart. Today, some half a million men and women, most of them over the age of sixty, carry implanted cardiac pacemakers that take over the duties of the natural conduction system. Tens of thousands of these devices are implanted each year in this country alone. Over the past thirty years cardiac pacemakers have evolved from simple devices only capable of fixed-rate stimulation of a single chamber of the heart to more sophisticated "implanted computers" that medical personnel can interrogate and reprogram from outside the patient's body. These refinements have allowed for more physiologic pacing with maintenance of atrioventricular synchrony and cardiac output. There are various types of cardiac pacemakers available today that can be surgically implanted to treat specific arryhythmic disorders in the heart. Abnormal rhythms in the heart are one of the most frequent causes of heart malfunction, and in most cases necessitate some type of cardiac pacing unit. Cardiac arrhythmias are common in the elderly, in whom age-related physiologic changes often alter the conduction system of the heart. Such changes may remain asymptomatic, or they may progress to syncope, or possibly sudden death. In the event of acute myocardial infarction, arrhythmias are no more frequent in the elderly than in younger subjects; in fact, ventricular premature beats are seen less commonly in patients aged seventy years and older. Age is also not a factor in determining the success of resuscitation from cardiac arrest, although it may be a predictor of six-month survival. In general, there is nothing unique about arrhythmias in the elderly. All of the commonly encountered arrhythmias may be seen in older patients. Arrhythmias may occur in otherwise normal hearts, but with increasing age, associated cardiac disease becomes more likely. A possible exception is atrial flutter; in younger patients, its presence almost always indicates a serious cardiac disorder. There are two indications for antiarrhythmic therapy: relief of symptoms and prevention of more malignant arrhythmias. In elderly patients, pacemakers are the preferred treatment for bradyarrhythmias. Most arrhythmias occur in response to the aging heart. In the sinoatrial node, the number of pacemaker cells decreases, until often less than 10% of the normal complement remain after age 75. Beginning at age 60, there is a detectable loss of fiber from the fascicles of the left bundle branch. Commonly, less than one-half the original number remain, the others having been replaced by fibrous tissue. Microcalcification is often found in this region, and can be related to both age-associated change and pathologic processes. There is also some fibrous tissue replacement of conduction fibers in the distal conduction system, as well as occurrences of fibrosis and hyalinization in the media of the blood vessels supplying the conduction tissue. Any of these age related processes can lead to a disrupted rhythmic and conduction system of the heart. One type of arrhythmia, bradycardia, normally necessitates the surgical implantation of a pacemaker device. Bradycardia is a circulatory condition in which the myocardium contracts steadily but at a rate of less than sixty contractions a minute. This condition may be normal in some physically fit people, where their pulse may be quite slow. This is because an athlete's heart is considerably stronger and is capable of pumping a larger volume of blood per heart beat than someone who is less physically active. However, in other people, cardiac output is decreased which can cause faintness, dizziness, chest pain, and eventually syncope and circulatory collapse. The cause of bradycardia can be an increase in the parasympathetic nervous system. As the vagus nerve applies more acetylcholine on the heart, the overall output of the heart decreases which means that there is less stroke volume. In addition, severe episodic bradycardia may occur in patients with a hypersensitive carotid sinus reflex. In these patients, their carotid sinus region of the carotid artery becomes extremely sensitive to the pressure receptors within the arterial wall.

What Impacts Did The 2005 Aichi Expo Help Nagoya, And Help Japan Play A Leading Role Globally Essays

What Impacts Did The 2005 Aichi Expo Help Nagoya, And Help Japan Play A Leading Role Globally Essays What Impacts Did The 2005 Aichi Expo Help Nagoya, And Help Japan Play A Leading Role Globally Essay What Impacts Did The 2005 Aichi Expo Help Nagoya, And Help Japan Play A Leading Role Globally Essay History was in the making on this historical date March 25, 2005 for Japan and the city Nagoya until the pen stops writing on September 25, 2005. This was the new beginning for Japan and its fourth-biggest city Nagoya, which sits between the other two major cities in Japan, Tokyo and Osaka. 1 The main focus here is that, is the history going to be full of negativity or full of positives by the end of September of 2005. The new beginning and start for Nagoya is suppose to put itself on the map and for the rest of the world to know what a fantastic city it is to live in. Did the new beginning come with a price tag or was it a green light from the start? What were the conflicts and the controversial problems before the 2005 Aichi Expo began? What were the results and the impacts of the Aichi Expo and did it help Japan play a leading role globally? The 2005 Aichi expo had many obstacles to over come before the event can take place in Nagoya on March 25, 2006. There where many critics, environmentalist, and residential problems and issue that needed to be resolved and thought out before major construction of the area get started underway. The 2005 Aichi committee needed to deal with the on-going debate with resident and environmentalist and trying to convince them that by hosting the Aichi Expo event on March 25, 2005. The event would bring good things to the city such as an increase in income, technology and state of the art architecture around the city. 2 Rather than brining in any negative aspects and hazards to the resident that could harm them or the environment. For that reason, the beneficiary of this major event would be the people of Nagoya. Despite with all the positive features and outcome there were still unpleased people. Critics and environmentalists preferred to have a much cleaner environment to be in, rather to have more pollution in the area. By hosting the Aichi Expo it brings a lot of concerns to the people and negative environmental issues that need to be resolved. Environmentalist are concerns with the lost of habitat, an increase of pollution and the lost of traditional way of living in the area. Everything is dramatically going to change into a modernization way of living in Japan where robots and machines do the physical and manual labor where it is required, while the citizen sit back and relax. 4 One of the environmentalist concerns is the lost of the Isahaya Wetlands and with the proximity of the Fujimae Wetlands close in the area it would cause a stoppage of migratory birds. The area records an astonishing number of 12,000 birds a day for a stopover in the spring. The birds are at risk of losing one of their most important feeding and resting place, where they migrate from Siberia have a stopover and go to Australia. Another major negative environment concerns is that Nagoya one of the biggest city and with a big city it comes with a waste disposable problem and the cost of staging the exhibition 2005. Thus, leads to a large amount of pollution and waste being emitted and dumped into the air and streams killing habitants in the area. On top of that the governor Reiji Suzuki is encouraging a progression of inefficient, environmentally destructive public work projects, that is supposedly to prime the local economy. 6 With all the projects that are projected to finish for the 2005 Aichi Expo it would cost an estimated Y350bn (Dollars 3. bn). 7 One significant lost to the Nagoya area is the Setos Kaisho Forest, enclosed in the area lies some of the most biologically rich regions and home to numerous endangered species, such as insects, birds and plants. The vicinity in the surrounding area would be destroyed to make room for the Expos pavilion. A major highway that would disturb the species in the area and disrupt the watershed and pollute the mountain streams because of the highway is being built and cut through the middle of the forest. As a result, local traffic and tourist going to the event causes air pollution which kills the forest and prohibit species to live in the area. 8 Despite all the negativities that come with hosting the 2005 Aichi Expo, it also comes with quality features and positive outcome for Nagoya and Japan. It generates and increases the amount of revenue, the amount of tourist and that is estimated to reach about 15 million people but that number can exceed that threshold and for that reason it will expose Nagoya to the world. By exposing Nagoya, it helps the city and Japan in the economic aspect. For many years now Nagoya has been in the shadow of Osaka due the proximity of the two cities and Osaka is the one getting the lucrative investments by investor because Osaka is considered to be the entrepreneurial and industrial of Japan. 10 But that is all going to change because Nagoya is putting out a strong effort and a significant change to the fourth largest city in Japan. The exhibitions chief producer Shohei Fukui grantees the change and that Osaka will not only be the city that has a global focal point. For that being said and done, Nagoya has built many infrastructure, and an advance technology on transportation and facility on how to sustain a cleanse environment. 11 The expo majors theme is called Natures Wisdom. With the theme name Nature Wisdom, that is exactly what the exhibition committee plan on carrying out. With the new technology advancement they would have to destroy parts of nature to accomplish this goal. But as well, the committee has to acknowledge the concerns about environmental issue, technological and cultural concerns about local and global development. The advancement technology that Japan has in store for the future way of living is unbelievable. The advancement technology includes transportation, top notch facility to make the environment a cleaner place and for future plans on how to live a sufficient life without much pollution. 13 The new transportation system install would be a big improvement for the residents to travel from place to another. Some new installment includes the Multimode Transportation System (IMTS) vehicle, the fuel cell hybrid bus (FCHV), and the Linimo. With the Multimode Transportation System (IMTS), it is an independent operation system like a normal bus, high speed, the capacity of passenger is 50 and its convenience of not having to transfer multiple vehicles. Has a glass structure cabin giving it a panoramic field of vision and is field with clean compresses natural gas. The fuel cell hybrid bus (FCHV) runs on motors powered high-pressure hydrogen supplied fuel cells and a nickel metal hydride secondary battery. The beauty of this hybrid bus is that its highly energy efficient and it doesnt emit carbon dioxide which is unsafe for the ozone layer not like gasoline and diesel fueled vehicles. The hybrid bus has a high running efficiency rate by recovering energy during deceleration and it also can adjust to the running conditions. The bonus to this fuel cell hybrid bus is that it runs smoothly and very quiet so it would not disturb the resident from unwanted noises. For the Linimo vehicle its based on railway and shuttle buses that have the conveniences of that transport visitors from the parking areas to the exhibition sites.