How Exercise Can Help Prevent Coronary Heart Disease - Literature review Example

Coronary Heart Disease Order No: 209578 No: of pages: 19 Premium 6530 Literature Review Coronary Heart Disease or CHD: There is nothing better than a healthy heart in a healthy body! The facts are that very few people realize or understand it till it is too late. Coronary heart disease or CHD as it is called affects millions of people all around the world. Coronary heart disease is the single largest killer of American adults with more than 13 million having been diagnosed with heart disease.(American Heart Association, 2003) It is one of the most dreaded diseases and should gain a lot more attention than it is already given. The Coronary Heart Disease is considered as one of the most deadly diseases that is widespread and rampant in the United States and the issue of how exercise helps in alleviating or minimizing this disease is what this dissertation will discuss. According to Cowie and Kirby, “Impairment of left ventricular systolic function is the most common underlying problem”. (Cowie and Kirby, 2003) Coronary Heart failure or CHF is caused by the reduced capacity of the left ventricle of the heart to pump blood to the different parts of the body. Most cases of CHF are due to CHD, either occurring alone or in combination with hypertension. (DH, 2000, Stewart and Blue 2004) Major changes have taken place during the last decade due to research and as Cleland et al (1998) states that, “Current treatment aims to relieve symptoms and to prevent onset or delay the progression of CHF”. (Cleland et al 1998) The architects of the new General Medical Services (GMS) contract have classified heart failure as “an important chronic condition in patients that is not always managed optimally in primary care and as one with high morbidity and mortality”. (Standing 2006) Responding to data from the Health Survey for England published by the National Centre for Social Research on 31st January 2008, the British Heart Foundation (BHF) said that “Great strides have been made in reducing the rate of premature death from heart disease which means ever greater numbers of people face the daily struggle of living with this often debilitating condition. (BHF, 2008) Causes and Symptoms of Coronary Heart Failure: The statistics taken by the BHF states that obesity is a major problem and unless the rise in obesity is reversed, we risk a significant future increase in the rate of premature death from what remains “Britain’s biggest killer.” (BHF, 2008) The chief cause of Coronary Heart Disease is when fatty material, scar tissue (plaque) and calcium builds up along the walls of the arteries that supply blood to the heart. The coronary arteries have the job of conducting nutrients and oxygen to the heart muscle also called the myocardium that needs it in order to be able to pump the blood. This plaque that gets layered along the artery walls, narrows it further and hence the heart does not receive enough blood which is of utmost importance for its proper functioning. Due to this the blood flow is restricted to the heart and causes angina or chest pain. If in case the arteries become completely blocked then it could cause myocardial infarction which is nothing but a heart attack or cardiac arrest. Other causes include myocardial infarction (MI), valvular heart disease, abnormal cardiac rhythms, pericardial disease, congenital defects and viral infection. (Cowie and Kirby 2003) Two of the most common symptoms that are regularly reported are fatigue and breathlessness following any sort of exertion on the part of the patient. This is due to the cardiac disorder which impairs the ability of the heart to function normally. Impairment of left ventricular systolic function is the most common underlying problem. (Cowie and Kirby, 2003) Another cause for the rise in the prevalence of CHF is because of the increase in the proportion of older people in the regular population and partly because improved treatment of CHD and acute MI means that more patients survive to develop CHF or to have chronic left ventricular dysfunction. (European Society of Cardiology, 1995) According to many population based studies, there is rising evidence that the prognosis of CHF is beginning to improve with the introduction of more effective treatments. (MacIntyre et al, 2000) Assessment of Exercise and Heart Failure Treatment: Heart Failure syndrome such as CHF is characterized by hypertension where the cardiac muscles hypertrophies when responding to higher resistance and displays various kinds of symptoms associated with exercise. Therefore in order to evaluate the efficacy of ones heart exercise testing is of prime importance. This assessment includes testing ones level of fatigue or breathlessness which in turn reflects the condition of the heart. Exercise testing conducted in patients suffering from chronic heart failure is very necessary as it helps in many ways – Diagnosing the underlying causes of heart failure. Assessing the amount of risk and the severity of the disease. Monitoring responses of the given treatment. Exploring the various limitations associated with the pathophysiology of various exercises undertaken for heart failure. Lastly, Using exercise as a prescription for selected heart failure patients in order to reduce the symptoms and encourage better outcomes. This study is going to focus on patients suffering with CHD where exercise is going to be utilized as a potent tool in increasing the health of a patient’s heart. Safety in Accordance with Exercise Training: According to Clark, many of the heart failure syndrome features also occur in normal subjects who have de-trained themselves resulting in peripheral muscle atrophies and a consequent decrease in strength. (Clark 1996) The duration of exercise is a good way to check the capacity of the heart in relation to the amount of wear and tear. For example during exercise, a patient with atrial fibrillation would experience an inadequate chronotropic response which would serve as a predictor to show the severity of coronary heart disease. Therefore, it is quite necessary to record the patient’s heart rate at rest and also during exercise. It is not only safe but also vital to monitor blood pressure responses in patients with heart failure. In case there is a drop in blood pressure, it is an indication of a poor or deteriorating function of the left ventricle. When such is the case it is advisable to be on the safe side and stop the test immediately. Monitoring a patient’s rhythm during an exercise session is vital for safety. In addition to this, the clinician also checks for altered consciousness, development of angina, oedema and fluid retention for both safety and diagnosis. Exercise Tests for Heart Failure Patients: Generally, it is better and much more useful to keep a watch over patients who are undergoing the exercise tests as it is much easier to arrive at a reliable and accurate assessment of the patient’s heart. One of the simplest tests include getting the patient to walk up and down the corridor of the out- patient unit and gauging the changes in the patient’s heart rate and ventilation and looking out for any signs or possible symptoms. Before and after the walk it is advisable to use pulse oximetry to check on the patient’s breathlessness and desaturation levels because such patients are highly likely to possess pulmonary pathology. Other formal exercise protocols could be broadly classified as maximal and sub- maximal tests. Maximal Tests: Maximal tests involve utilizing incremental protocols of either a cycle or a treadmill while urging the patient to exercise till exhaustion. To elicit the patient’s highest peak of oxygen consumption, the test should last for at least 10 minutes. The popular treadmill protocols are the modified Bruce and Naughton protocols that are widely utilized. The Cycle protocols are also commonly used and are merited for clearly defining oxygen ranges in patients by using specific workloads during exercise training. Sub – Maximal Tests: Since maximal tests are at most times not too accurate in assessing a patient’s daily activities, the sub- maximal tests have proved to be more efficacious in making a clear assessment of a heart patients symptoms. This involves a six minute walk test, “during which subjects walk as far as possible during six minutes, at their own pace, is widely used”. (Olsson LG, Svedberg K, Clark AL, et al., 2005) Clinicians also advocate the shuttle tests which has patients walking from point to point with a signal that increases its frequency gradually. Care should be taken to see that the patient’s pulse and heart rate are continuously monitored and complete resuscitation facilities should at all times be available and close at hand. Though there is much concern that such exercises for patient’s suffering from chronic heart disease could be dangerous, yet, these exercises have repeatedly been found to be reasonably safe. Tests Involving Metabolic Gas Exchange: To measure the patient’s inspired and expired air clinicians use modern metabolic gas exchange equipment such as rapid gas analyzers to find out the differences between them and thus the indices for metabolic gas exchange can be measured instantaneously. Inspired air comprises of 20.9% of molecular oxygen and almost no trace of carbon – dioxide and expired air contains less oxygen and approximately 5% of carbon – dioxide. The patient is asked to wear a tight fitting mask over his face and he is asked to breathe through a mouth piece having nasal grips so that expired air is prevented from leaking out. Using one way valves helps to ensure that the patient breathes normal room air. The air that is expired is collected and sent for analysis. Using a pneumotachograph, each breath is measured to check the amount of oxygen consumed and the amount of carbon – dioxide produced and the average of three inferences are drawn. Another approach to measure a patient’s inhaled and exhaled oxygen and carbon – dioxide levels would be to utilize the mixing box. Here the exhaled air is collected and a tracer gas such as helium is mixed. A system of baffles helps in the mixing which very much represents something like the Douglas bags. While going through the incremental exercises the patients V˙O2, V˙CO2 and V˙E are tabulated. The patient’s peak oxygen consumption is calculated as the maximum tolerance of exercise by the patient. The maximum oxygen consumption of the patient is arrived at when there is no increase of Vo2 during incremental exercise even though the load of exercise is increased. This is how the (RER) Respiratory exchange ratio is calculated which is the ratio between oxygen consumption and carbon – dioxide production. Utilizing the metabolic gas exchange measurements proves invaluable in helping to select patients for heart transplants. “The value of 14 ml/kg/min is generally taken as the cut-off point below which patients should be considered for transplantation”. (Mancini DM, Eisen H, Kussmaul W, et al. 1991) Exercises vary according to the severity of the patient’s disease. In case of patients suffering from CHD the exercises could be a little more elaborate than when compared to patients with CHF. So based on the patient’s disposition, appropriate exercise training programs should be scheduled. Prevention and Cure of Coronary Heart Disease: Heart failure has been included in the General Medical Services (GMS) framework as a part of the CHD clinical domain. Heart failure is been identified as an important chronic condition in patients which is not being managed optimally as one with high mortality and morbidity. Patients are rarely prescribed any form of exercise and effective therapies for the cure of CHD are under-prescribed. Specialist nurses could help patients with CHD in overcoming deficiencies. (McMurray and Stewart and Blue 2004). Specialist nurse intervention in CHD showed marked improvements in patients according to a trial conducted. (Blue et al 2001).Inter-disciplinary approaches incorporated by the specialty nurses improved the health of CHD patients. “They also reduce hospital use, are cost-effective and help improve patients’ overall quality of life” according to Rich et al (1995).The success ratio of this therapy is solely because of regular contact of the nurses with the patients to detect clinical deterioration and also due to the continued adjustment and optimization of treatment.” (McMurray and Stewart 1998).Home visiting has been known to reduce admissions, by ensuring that patients have regular and effective contact with the nurses (Stewart et al 1999) Treatment begins as soon as the patient is diagnosed for either primary or secondary heart disease. In response to so many patients being hospitalized many hospitals are trying to give specialized care by using the multi- disciplinary approach in order to reduce the readmission rates of patients suffering from heart disease. This approach gives continuous care alongside patient education in the area of self management. Through using such an approach the medical fraternity is well on their way to overcoming the barriers of effective management of heart patients. The multi- disciplinary approach is not only cost effective but it primarily enhances the quality of life for the patient. Patient Assessment: Before beginning any exercise training program the patient should be given a thorough assessment. This is because it has to be ascertained whether the patient is suffering from CHD or CHF because different levels of the disease require different exercise training programs. When this is done, a specific plan of action should be drawn up and necessary monitoring and evaluation carried out to check on how far the disease has progressed. This step is indispensable because only then the correct exercise training program could be prescribed. Though effective treatment may improve the patients’ quality of life and the symptoms of CHD, still survival rates remain poor. Around 50 percent have a five-year survival rate estimate which decreases to less than 20 percent in people aged 80 years or more (Kelly and Kelleher 2000) Healthcare professionals are increasingly using the New York Heart Association (NYHA) classification of CHF; methods of treatment which are linked now to this classification (Cowie and Kirby 2002). The multi – disciplinary approach is gaining much popularity because of its special and systematic approach which has helped to reduce the number of patients being re-hospitalized. Pharmacologically there is evidence supporting the use of beta blockers in those patients with stable CHF. Recent trials have shown that the addition of certain beta blockers to a regimen consisting of diuretics and an ACE inhibitor could result in improving the left ventricular function, symptoms, hospital admissions and survival itself (Gibbs et al 2000). The advantages of ACE inhibitors in CHF are documented to be the best drug for treatments of this condition (National Prescribing Centre 2001). Diuretics can pave way for symptomatic relief (DH 2000).In severe CHF, spironolactone in addition to other treatments in a low dose of probably 25 mg everyday, could reduce mortality and morbidity (Pitt et al 1999). Patients suffering from CHF should be advised on various risk factors such as diet, alcohol intake, smoking, and also low levels of physical activity (DH 2000). Family members and patients need to spend a lot of quality time in trying to bring about lifestyle changes effectively. The best way to do this would be is to first understand well about the disease by educating themselves on this subject as well as the impact of exercise and sports on a person’s heart., so that they would be in a better position to render all the help and care their loved one needs. Their help would be very beneficial especially during the exercise training programs. Exercise in Chronic Heart Failure: A patient’s exercise capacity is reduced because of chronic heart failure. In the six minute walk tests he covers a relatively shorter distance and his performance is proportionately reduced in the shuttle tests too. When conducting the incremental tests, the duration of exercise time is lessened, and so also for peak V˙ O2. Therefore the exercise protocol that is chosen should last for about 10 minutes in order to maximize peak V˙ O2. The anaerobic threshold is relatively reduced but is still approximately the same as in the case of normal subjects. The patients with chronic heart failure have a relatively low oxygen pulse (oxygen intake for each heart beat) and a very poor blood pressure response to exercise. Hence it becomes somewhat harder to predict the heart rate response especially considering that many of the patient’s are on blockers. Taking into consideration the peak ventilation of normal subjects it is around 120 liters/min. but the peak ventilation in heart failure patients the peak ventilation is about 50–60 liters/min. Hence breathlessness is more evident during any given ventilation than normally what occurs. Besides these other evident abnormalities during exercise in patients with chronic heart failure is “impaired diffusion at the level of the alveolar-capillary membrane.” (Puri S, Baker BL, Dutka DP, et al., 1995) Another crucial observation that was made was that “arterial blood gas tensions are normal, or even supra-normal, in heart failure, with a rise in PaO2 towards peak exercise, and fall in PaCO2. Any abnormality of blood gases (including a fall in arterial oxygen saturation) should prompt a search for other pathology. (Clark AL, Coats AJ, 1994) Role of Exercise for a Healthy Heart and Coronary Heart Disease: Over the past 20 years there have been changes in opinions regarding physical activity in CHD affected patients. Earlier, patients with ischaemic heart disease and chronic heart failure were completely advised against any heavy activity, whereas contemporary guidelines recommend exercise training for both kinds of patients. There are many benefits evident from regular exercise and physical activity in the prevention of cardiovascular disease. Inactivity has been known to be the primary risk factor for cardiovascular disease and mortality in general. Low levels of aerobic fitness and obesity are contributors to the disease. Discussion: From a clinical point of view, making a thorough study of each individual patient is not only very useful to the patient but it also acts as an encouragement or help them to be motivated in pursuing exercise training and to continue an active lifestyle. For many different reasons exercise testing that is symptom limited together with measurement of peak VO2 is a common procedure for all patients entering into CR. Such testing supplies important prognostic information and also caters to exercise safety. It also serves as a guide for individualized exercise training with the Peak VO2 being measured directly during the exercise tests or calculated using the maximal exercise capacity of METS. In this study of peak V˙O2 that involved patients going in for cardiac rehabilitation (CR) soon after a coronary incident, 2896 patients were examined, analyzed and the results collected. Women were found to show a rather very low Peak V˙ O2 such as those seen in patients suffering from extreme chronic heart failure. Based on these results it goes to prove the importance of CR exercise training programs for such patients. However, according to a new finding, there is a relatively higher increase in peak VO2 in male participants, when compared to their female counterparts. (18% versus 12%; P_0.01). “Although the women in this study were older than the men, studies have not shown a different relative improvement in peak V˙ O2 response to training by age or gender”. (Ades PA, Grunvald MH. et al (1990) This means that the VO2 of patients is not based on either age or gender but it depends on the extent of the disease and the patient’s capacity to cope with the exercise program during rehabilitation. Besides ones gender, the other primary factors that showed low fitness were older age, the occurrence of angina during the stress test, obesity, CABG surgery, and type 2 diabetes mellitus and hypertension,. Nomograms are used to determine the patient’s percentage of predicted peak V˙ O2 in relation to their age, gender, and existing diagnosis. This diagnosis is imperative to prescribe the right exercise training program for the patient. The impact of age on peak VO2 was also significant. For men in their 40’s to men in their 80’s, the peak VO2 decreased by about 39%. Each decade was measured sequentially – form 40 to 50 years of age, 50 to 60 years of age, and so on right up to the age of 80years. The peak V˙ O2 dropped steadily by 11%, 11%, 14%, and 11%, respectively, or _0.242 mL · kg_1 · min_1 per year. In the case of women the drop was relatively less with a decrease of 22% from the age of 40 to the age of 80years. (P Read More