Atrial fibrillation (AF) is a common disease that affects the electrical system of the heart. If not treated promptly, AF will lead to serious complications such as heart disease and stroke, to name a few. The heart is in charge of circulating blood to ensure that it circulates across the body. A natural heart has “atria” (top chambers) and “ventricles” (bottom chambers) that are responsible for pumping. In a stable heart, the atria contracts first, forcing blood into the ventricles, which then contract (right ventricle) pushing blood into the lungs and the left ventricle circulating blood to the rest of the body, and the process repeats itself. The action of contraction in the atria is ignited by electrical signals which originate from the “pacemaker” in the heart. The same signals are sent to the ventricles to trigger pumping into the lungs and the rest of the body.
When an individual has Atrial Fibrillation, waves of uncontrolled electrical signals are sent to the atria. This is in contrast to the normal signals which are always highly controlled originating in the sinus. These usually originate from some of the four veins tasked with bringing blood into the heart from the lungs. The electrical waves result to the atria quivering, which may result to part of the electrical signals being transferred to the ventricles which cause the heart to pump blood irregularly. This irregularity in pumping makes the heart less effective.
Pathophysiology
Atrial fibrillation has a characterization of chaotic and uneven atria activation that leads to undesired contraction and relaxation of the atria. Reportedly, new cases of AF rises as people grow up (increase in age), with individuals of ages over 80 years being the most prone to this condition, its first instance being recorded and put in writing by “Thomas Lewis” in the year 1909 (Nabar & Pathan, 2016). AF’s pathophysiology is a matter whose research is ongoing, with more sophisticated curative and preventive measures being developed over time. It is a disease that develops with time and with time, underlying conditions may worsen and lead to further problems. During first instance diagnosis of a patient, AF is referred to as the first diagnosis, and as the condition keeps repeating to show symptoms, it may be recorded in various ways and is classified as: permanent; symptoms appear for a period of more than one year, long-standing persistent; symptoms appear in episodes for more than a year, persistent; AF appears continuously for 7 days or more and where cardioversion is needed and finally paroxysmal; the condition is continuous but stops without any intervention after 48 hours (Nabar & Pathan, 2016).
Structural remodeling: in this case, the basic pathological change noticed in AF is atria progressive fibrosis, which is majorly caused by dilation of the atria. Atria dilation can be as a result of any heart structural abnormalities that can lead to a pressure rise in the heart. Valvular diseases of the heart, congestive heart failure of hypertension compose of some of the abnormalities. Fibrosis (of the atria) can also be caused by the heart’s inflammatory states such as an autoimmune disorder (sarcoidosis) which results in the generation of autoantibodies. Mutations in a gene known as lamin AC has also been found to cause fibrosis. Atria dilation results to renin-aldosterone-angiotensin system being activated which increases disintegrin and matrix metalloproteinase deposition on the walls of atria (Nabar & Pathan, 2016). Muscle separation is due to the occurrence of reactive interstitial fibrosis, and dead cells are replaced by reparative fibrosis, this results in the interference in the continuity of electric pulses, and also conduction is slowed down. Fibrosis has serious implications such as making paroxysmal AF permanent.
Etiology
AF has several factors and health conditions which can be regarded as causative factors. These include aging, genetic complications and factors, neurologic disorders, endocrine disorders, drug abuse and alcohol, inflammation of the heart, atrial ischemia and hemodynamic stress (Rosenthal, 2017). These are expounded on in the text here-below.
As people’s age advance, research has shown that atrial fibrillation is rampant in old age and that more than 8% of individuals beyond the age of 80 years and more than 4% of individuals of the age beyond 60 years are prone to be affected by the condition (Rosenthal, 2017). Genetics studies have shown that individuals coming from families that have experienced AF have a higher probability of being affected than individuals whose family members record no instance of this ailment. Neurologic disorders such as stroke have also demonstrated a capability of leading to this condition.
Disorders that are regarded as endocrine, to have a contribution in leading to atrial fibrillation. Alcohol and drug abuse is another relating factor to this pandemic. Examples of substances regarded to trigger the condition include cocaine and alcohol (Rosenthal, 2017). Abuse of drugs such as cocaine and excessive alcohol consumption, when repeatedly done, have been discovered as having a close relationship with AF. These are just some of the many factors related to this illness.
Pathogenesis
Atrial fibrillation is one of the most common types of irregular heartbeat. In the United States alone, the number of individuals affected is more than 6.1 million. Due to its characteristic of affecting people as they proceed in age, (Rosenthal, 2017), individuals aged above 60 years are 4% affected, and 8% of those who are 80 years and above. Research has indicated that for those who are of 40 years and above, 25% of them will develop the condition. By the year 2050, the number of people affected by AF is projected to be twice the count today due to the increase in the elderly population. More men than women are affected by the condition and more white people than black (Rosenthal, 2017).
Morphologic Changes
Morphological changes brought about by AF includes variations in the atrial myocardium. The main causative agents with abilities to make changes to the myocardium structure include atrial tachycardia with high percentages of depolarization of cells and overload due to stretching of atrial walls. The affected parts not only experience electrophysiological changes but also structural changes such as contractile dysfunctionalities. These may lead to worsening of any existing heart conditions and therefore causing the myocardial damages to get worse. Developing this cycle makes paroxysmal AF develop into more complicated forms of atrial fibrillation.
Clinical Manifestations
Being a condition that experiences irregular heartbeats, it also features certain depolarization. If termination of AF is after a short period, it is referred to as paroxysmal AF, if on the other hand, it is regarded as persistent if it persists for seven days or more. Patients who are termed “critical” experience high blood pressure (hypotension), myocardial ischemia and extreme cases have even led to heart failure with dysfunction of organs and tissue hypoxia. These are majorly caused by the absence of atrial contraction that leads to the inability of the heart filling the ventricles (Arrigo, Bettex, & Rudiger, 2014).
Diagnosis
Diagnosis of atrial fibrillation is done basing on an individual’s results from procedures and tests, physical examinations, family and medical history. There are instances where AF does not show itself, and it is discovered through tests meant for other conditions such as electrocardiogram tests. It is important to determine the causes of the condition as it will enable the pediatrics to determine the best way of administering treatment. There are special doctors who specifically deal with heart conditions; these may include electrophysiologists and cardiologists. But also other doctors can be involved in the diagnosis and treatment of the same (National Heart, Lung and Blood Institute, 2014).
Clinical Course
Treatment for patients with atrial fibrillation can be administered in various ways. Examples of methods of treatment include: improving the quality of one’s life, heart rate control and preventing strokes from happening. Patients also need to be given therapies and counseling, which requires the person prescribing to possess knowledge on most of the clinical matters such as mortality and cardiovascular events (Piccini, et al., 2013).
Summary
Individuals with atrial fibrillation describe the experience as “unpleasant, alarming and sometimes unexpected heart sensations.” They explain that their hearts beat at very fast frequencies, comparing the heartbeats with the flapping of a butterfly, “like you have a ferret in your chest and a bird in there jumping around.” These descriptions match the descriptions given in the clinical description of atrial fibrillation, that it is a condition that experiences irregular heartbeats, due to the interference of atrial electrical pulses resulting to “quivering” of atria.
References
Arrigo, M., Bettex, D., & Rudiger, A. (2014). Management of Atrial Fibrillation in Critically Ill Patients. Critical Care Research and Practice.
Nabar, A., & Pathan, I. (2016). Pathophysiology of Atrial Fibrillation – Current Concepts. Journal of The Association of Physicians of India, 11-15.
National Heart, Lung and Blood Institute. (2014, September 18). How Is Atrial Fibrillation Diagnosed? Retrieved from National Heart, Lung and Blood Institute: https://www.nhlbi.nih.gov/health/health-topics/topics/af/diagnosis
Piccini, J., Hammill, B., Sinner, M., Hernandez, A., Walkey, A., Benjamin, E., . . . Heckbert, S. (2013). Clinical course of atrial fibrillation in older adults: the importance of cardiovascular events beyond stroke. European Heart Journal, 250-256.
Rosenthal, L. (2017, April 10). Atrial Fibrillation. Retrieved from The Heart Medscape.org: https://emedicine.medscape.com/article/151066-overview#a4
