Causal Factors and Pathophysiology of Atrial Fibrillation - Research Paper Example

Atrial Fibrillation Atrial Fibrillation Introduction Atrial fibrillation (AF) is a widespread type of arrhythmia globally affecting nearly 34 million people aged 75 and over (Chugh et al, 2014). The disease involves the atria - the upper cardiac compartments. During AF, electrical impulses of the sinoatrial node are suppressed by the signals originating in the pulmonary veins and atria. As a result of this abnormal activity, irregular impulses reach the ventricles and produce irregular pulse. In such a condition, heart pump works inefficiently, and tissues receive less blood, which may lead to a number of complications such as stroke and even death. Epidemiology According to Bashore et al (2013), AF occurs in 10% of people above age 80. Generally, AF affects about 3% of the population in Europe and the US. The numbers increased by 1% between 2005 and 2014 In the developing countries, incidence is estimated to reach 0.4% for women and 0.5% for men (Lercari et al, 2014).  In a UK-based study, Framingham revealed that the risk of getting AF after 40 equals to one in six, regardless of sex, and one in for in individuals with a history of heart failure (Cottrell, 2011). The analysis of over 0.5 million cases in England allows to assume that males are more likely to develop AF than females (NCC-CC, 2006). However, there is an assumption that the real numbers are higher, since the screening does not cover the entire population (NHS Improvement, 2009). In the UK, 45.000 new cases are registered annually (Iqbal et al, 2005). Causal Factors Occurrence of AF implies organic lesion of the heart. Common cardiac causes include IHD, rheumatic heart disease, hypertension, cardiomyopathies, and heart failure, while some non-cardiac are the acute infection and lung and thyroid pathology. AF can also be iatrogenic and develop after the surgical manipulations in the thorax (NCC-CC, 2006). Apparently, AF would not develop without the damage to the cardiac tissue. The lesion becomes the reason why extra stimuli are being generated. The reparation processes in cardiac muscle, stretching and proliferation place more pressure on the atria, which, in turn, increases the pressure in the pulmonary veins. Such condition is known to be the precursor of heart failure, atherosclerosis, obesity, and valve disease – the direct causes of AF (Larson, 2009). Age is considered to be a principal risk factor for AF, as the incidence ascends from 0,5-1% of the population aged 50 to 23% of people over 80 years (Westerby and Cottrell, 2011). As far as metabolic syndrome, diabetes, and hypertension lead to IHD, they also form a group of risk factors for AF. Despite the unidentified sole cause of the AF, some researchers suggest the involvement of the genetic factor. Therefore, a study on more than 2,100 patients discovered that 30% had a family history of AF (Fox, 2004). Pathophysiology Normally, the heart beat is under control of the pacemakers of the heart. The first-line pacemaker called the sinoatrial (AS) node comprises electrically active cells located in the right atria. The impulses arising from the ion exchange generate excitation that quickly spreads across the atria and forces them to contract and evacuate the blood into the ventricles. The atrioventricular (AV) node serves as a secondary pacemaker and functions to decelerate the heartbeat. After a short interruption in the AV node, the excitation travels along the bundle of His, initiating depolarization of the ventricles that contract and eject blood into the vessels. AF appears as an outcome of the anomalous impulse route when the excitation starts in the regions other than the SA node. Electrical signals are being produced in many parts of the atria, which leads to accelerated but chaotic and inefficient atrial contractions. In AF, the frequency of contractions may reach as much as 600 beats per minute. Because of the extreme rate of signals coming from various loci, the AV node fails to fulfill its filtering function and the atria are unable to empty each time. Apparently, it is the malfunction in the AV node that the accelerated heartbeat may be attributed to. Sometimes, the ventricular rate can be as frequent as 130 beats per minutes and more. In case of the prolonged impairment, the physical condition deteriorates and signs such as chest pain, fatigue, and breathlessness occur. The continually inadequate evacuation of blood into the ventricles may result in blood clots being formed in the LAA. The possible negative consequence of blood stasis in the atria is that the clot may crumble and the particle may occlude the brain vessel causing a stroke. Clinical Presentation Typically, AF presents with symptoms related to the accelerated heartbeat. Patients often perceive the high irregular heart rhythm as palpitation or physical activity intolerance and, in cases when the increased heart rate provokes ischaemia, produce angina. Other common symptoms are swelling, breathlessness, generalized weakness, and dizziness. In approximately one-third of the patients, AF may long remain unnoticed. It is not unusual that AF is diagnosed only with the manifestation of stroke. Frequently, it is after a routine ECG that a person hears about arrhythmia (Fuster, 2006). Some of the symptoms may be attributed to the physiological process of ageing. However, a thorough examination and history taking will help in noticing AF. It is recommended for all individuals with palpitations and breathlessness to turn for medical consultation. Complications Possible complications of AF are mainly thromboembolic in nature and include cardiac arrest and stroke. In serious cases a lethal outcome is possible. Sometimes, AF does not manifest clinically and such individuals are unaware of the dangers the condition holds. Frequently, patients encounter the diagnosis of AF after stroke has already developed. The risk of acute cerebral circulation impairment is proven to be five times greater in individuals with AF (Lee et al, 2012). Furthermore, Atarash and Inoue (2000) revealed a direct correlation between ageing and the risk of stroke. The researcher reports of a 3.3 stroke index in persons over 65. In another study, it was discovered that a quarter of patients delivered to the emergency room with stroke also suffered from AF. Moreover, AF was the definitive cause in 17% of the stroke deaths (Marini et al, 2005). Apparently, there is a strong reason to imply that a more thorough screening for AF would significantly reduce the number of fatalities. For instance, Turner et al (2010) claim that a great percentage of the elderly people do not receive the anticoagulants they need to take. Such situation may be partially rationalized by the high risk of bleeding concerns in patients receiving anticoagulants. To challenge the issue, the HAS-BLED risk score was designed. The scale gauges such clinical factors as age, blood pressure, liver/renal function, history of bleeding and stroke, and exposure to alcohol and medical substances. The score equal to or greater than 3 signifies of the potential complications of anticoagulation therapy (Lip, 2012). Diagnosis In order to detect the disease on time and avoid dangerous complications, it is advisable to perform the screening for AF during consultations for other illnesses such as diabetes, asthma, or hypertension. The screening should include peripheral pulse control and ECG. Sometimes, physicians identify irregularities of the pulse, which can be characterized as some beats being weaker or stronger than the others. In case such abnormalities are noticed, a 12-lead ECG should be performed to verify the diagnosis of AF. A standard ECG during AF will feature the reduced voltage or absence of p-waves that reflect electrical activity of the atria. A thorough physical examination should be accompanied by a profound medical history since it is important to know when the disease presented and how the symptoms progressed over time. It is crucial to remember that most people may experience difficulties when intending to express their symptoms. Henceforth, doctors should use simple language and, in turn, anticipate explanations such as “discomfort in the chest” or “fluttering sensation” from the patients. Moreover, due to a frequent mental dysfuntion in the elderly patients, physicians should not ignore the opportunity to ask family members for information (Lee, 2008). Additionally, an echocardiogram may be done to as assess the function of the heart chambers and detect organic damage. 24-hour Holter will be helpful in cases when AF is not verified after ECG. Holter monitoring enables the continual control of the speed and rhythm of the heartbeat and assists in differential diagnosis between the arrhythmias. Treatment Options Physician’s approach to management of AF varies in accordance to the clinical presentation. Currently, the anti-AF arsenal includes a vast array of treatment options. Digoxin has been widely applied in not so long ago, but has been largely replaced with anticoagulants that are a better alternative. Beta-blockers are efficient in controlling the heart rate, and are usually first-line medications in curbing AF symptoms. Restoration of the normal rhythm may also be achieved via cardioversion. In cases where medication and cardioversion are not successful, AF ablation may be performed. In treatment of the AF, among the main doctor’s objectives is the prevention of potential complications. Anticoagulants are in the forefront of stroke prevention. Anticoagulants of the older generations include aspirin and warfarin, which have a limited therapeutic range. Therefore, warfarin therapy requires continuous monitoring and blood sampling to guarantee the efficient concentration of the drug in the blood. Moreover, if the International Normalised Ratio (INR) increases, bleeding may occur. It is recommended to keep the INR within 2.0 to 3.0 range. The present-day anticoagulants include dabigatran, rivaroxaban, and apixaban, which can be prescribed orally, and do not require the same preciseness in monitoring during the course as their predecessors. However, anticoagulants should be indicated on an individual basis since not all patients with AF can or should take it. Anticoagulation should only be prescribed the likelihood of stroke is increased. To access risk factors, the CHADS score should be used (Lip and Halperin, 2010). Zero points on the CHADS scale is relevant to a very low risk of stroke, meaning that no anticoagulants are required. A score of 2 and above would be an indication for anticoagulant therapy. Patient education As far as the improper use of or poor compliance to the prescribed therapy can have adverse health implications such as thromboembolism and bleeding, every patient receiving anticoagulants must undergo proper education. Nurses’ task on this part of health care is to provide the appropriate teaching and make sure that the patients are totally aware of the necessity of the measures taken. All patients should be acknowledged with a range of food products and substances that anticoagulants may react with. For example, the curative impact of warfarin is considerably distorted by vitamin K-rich spinach, arugula, and mustard greens. Interactions may also happen between warfarin and some herbs, such as garlic or biloba. Many individuals with AF also suffer from opportunistic illnesses. Therefore, it is vital for them to know about the possible medication-medication interactions. Even though the modern anticoagulants are minimally dangerous, all of them can interact with other drugs. Patients who receive antibiotics, antiepileptics or contraceptives should have their warfarin doses adjusted (Woo, 2011). Furthermore, patients should be explained why it is crucial to adhere to the schedule and take their medication timely. It must be emphasized that drugs are to be taken at the set hour each day to guarantee the efficient concentration stable in the blood (Russell, 2011). Finally, it is important to stress the importance of trauma prevention. Electric razors rather than the straight ones should be recommended for those who shave. In case of injury, individuals must immediately admit for the medical care if the bleeding does not stop within 15 minutes (Pezzotti & Freuler, 2012). Conclusion AF is a major health issue, running the risk of stroke and heart failure. Individuals with a verified diagnosis of AF should strictly comply with the given recommendations and adhere to anticoagulant therapy. Recently, substantial advancements have been made in approach to AF as the new generation of anticoagulants has been produced. Patient education is an integral part of success and, therefore, should not be omitted by healthcare professionals. References Chugh, S., Havmoeller, R., Narayanan, K., Singh, D., Rienstra, M., Benjamin, & Murray, C. (2013). Worldwide Epidemiology of Atrial Fibrillation: A Global Burden of Disease 2010 Study. Circulation, 837-847. Fox, CS. (2004). 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