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  Atrial fibrillation

Atrial fibrillation (AF or afib) is a disorder characterized by an abnormal heart rhythm or cardiac arrhythmia involving the two upper smaller heart chambers known as the atria. The heart normally beats involuntarily because of its intrinsic conduction system generating electricity initiated by the pacemaker called the SA (sinoatrial) node. The impulse generated spreads through the heart chambers and causes contraction of the cardiac muscles hence, pumping blood into the systemic circulation. In cases of atrial fibrillation, the supposed to be regular electrical impulses discharged by sinoatrial node are replaced by rapid, ineffectual and disorganized electrical impulses resulting in irregular heart beats.

Atrial fibrillation
Atrial fibrillation

Among the different types of cardiac arrhythmia, the atrial fibrillation is the most common. The risk of developing atrial fibrillation increases with advancing age. In some cases, an individual may spontaneously have sudden attacks of alternating atrial fibrillation and a normal sinus rhythm known as paroxysmal atrial fibrillation. Others may suffer with continuing AF as the dominant cardiac rhythm with inability to convert back to the usual regular sinus rhythm. This condition is called chronic atrial fibrillation. Atrial fibrillation is often asymptomatic, but may present clinically with symptoms such as palpitations, fainting, chest pain (angina pectoris), exercise intolerance or even congestive heart failure symptoms like edema and shortness of breath. These symptoms are especially common in instances like an atrial fibrillation with too fast or too slow heart rates. Moreover, due to the erratic movement of the heart chambers stagnation or stasis of blood occurs which increases the risk of thrombus (blood clot) formation. If this thrombus is dislodged then embolism may happen. The clot may travel within the circulatory system specifically from the heart chambers to the brain (via cerebral vessels) and other areas of the body. This is the reason why atrial fibrillation is an important risk factor for stroke (“brain attack”) or cerebrovascular accident (CVA), the most dreadful complication of atrial fibrillation.

Treatment of atrial fibrillation symptoms is basically through medications which slow down the heart rate. Several anti-arrhythmic medications such as digoxin as well as electrical cardioversion may be employed to convert the atrial fibrillation back to a normal heart rhythm. Surgical and cardiac catheterization modalities may also be used to prevent atrial fibrillation in certain individuals. Adjunct treatments commonly used especially for those people with chronic atrial fibrillation are blood thinners such as warfarin, an anti-coagulant to protect them from strokes.

In some cases, the arrhythmia may be initially identified with the onset of a stroke or a transient ischemic attack (TIA). An incidental finding upon a routine physical examination or electrocardiogram (ECG) is also common in identifying arrhythmia in other asymptomatic cases.

A form of AF which is difficult to diagnose is the paroxysmal atrial fibrillation which is also defined as a sudden episodic occurrence of the arrhythmia. The episodic attack of arrhythmia may occur with sleep or with exercise, thus may require a more prolonged ECG monitoring (e.g. a Holter monitor) for diagnosis.

Although AF is associated with several cardiac problems, it may also occur in an otherwise normal heart. AF is linked with the following medical conditions: high blood pressure (hypertension), mitral stenosis, mitral regurgitation, open heart surgery, coronary artery disease (CAD) or ischemic heart disease (IHD), hypertrophic cardiomyopathy, excessive alcohol consumption, hyperthyroidism, excessive stimulation of the vagus nerve, lung disease, pericarditis (inflammed pericardium, the membrane surrounding the heart), intense emotional turmoil, and congenital heart disease.

There are two main goals of treating atrial fibrillation: First is to prevent temporary circulatory instability and secondly, to prevent stroke or cerebrovascular accident (CVA). To achieve the first goal, the dictum is to control usually by slowing down the heart rate and control the rhythm. The use of anticoagulant drugs is of prime importance to decrease the risk of stroke in order to successfully attain the second goal of treatment.

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