Atrial fibrillation is a disease of the heart which may bring about abnormal heart rate and rhythm. This may be due to many causes. Before we go to its underlying causes, let us first recall the basic function of the heart. The heart is made up of two upper and two lower chambers. The upper chambers of the heart are called atrias and the lower chambers of the heart are called ventricles. Atrial fibrillation results when the atria contract at an excessively high rate and in an irregular way. Atrial fibrillation is said to be the most common type of arrhythmia which may bring about problems in speed or rhythm of the heartbeat. This disturbance is often caused by a disturbance in the electrical system of the heart.
Arrhythmia occurs when there are problems in the heart muscles and the electrical impulses that trigger the beating of the heart. The atria and the ventricles of the heart are made up of muscles. When the heart muscle tightens, the chambers shut off and pushes blood out of the heart. The control of the heart beat begins with the sinoatrial node which is a small clump of cells that are located in the right atrium. The sinoatrial node is the heart's pacemeaker and determines the contraction of the ventricles, thus creating the pulse rate. When the atrioventricular node receives a lot of impulses, atrial fibrillation occurs and there is irregular contraction of the ventricles, causing irregular and high heartbeats.
There are three types of atrial fibrillation: paroxysmal atrial fibrillation, persistent atrial fibrillation and longstanding persistent atrial fibrillation. Paroxysmal atrial fibrillation is a type of atrial fibrillation wherein there is sudden onset of abnormal electrical signals and fast heart rate which may suddenly stop on their own and resume again. These changes in heart rate can bring about various signs and symptoms. These symptoms can last for a few seconds, minutes or even hours and days. On the other hand, persistent atrial fibrillation is a type of atrial fibrillation that stops when the patient receives treatment. The other type of atrial fibrillation is longstanding persistent atrial fibrillation, also known as permanent atrial fibrillation. This type of atrial fibrillation cannot be restored by usual treatments and can be long-term.
Atrial fibrillation that starts suddenly is called acute onset atrial fibrillation. Atrial fibrillation may also occur after surgery. This Medical condition can bring about symptoms such as a fast heartbeat that is over 140 beats per minute, dizziness, light-headedness, confusion, palpitations, breathlessness, weakness, chest pains, heart failure, hypotension or low blood pressure and disorders of the heart muscle.
There are many causes for atrial fibrillation, some of which are older age, underlying heart conditions, hypertension or high blood pressure, coronary artery disease wherein plaque builds up inside the blood vessels of the heart, congenital heart disease wherein there are problems with the structure of the heart starting at birth, mitral valve disease which may cause abnormal leaking of the blood from the left ventricle into the left atrium, cardiomyopathy which may cause inflammation of the heart, previous heart surgery, hyperthyroidism, sleep apnea, alcohol abuse, smoking, excessive caffeine consumption, and atrial flutter. Several chest infections and other conditions can also give rise to atrial fibrillation such as pneumonia, lung cancer, emphysema, chest infections, pulmonary embolism and carbon monoxide poisoning.
Atrial Fibrillation and High Blood Pressure
A recent study shows that poor blood pressure control in patients with atrial fibrillation is associated with a 50 percent increase in the risk for stroke. This study done by researchers from Duke Medicine suggests that hypertension should be carefully monitored and controlled in patients with atrial fibrillation. Data obtained by the researchers were from a large clinical trial called ARISTOTLE, which in turn utilized data from more than 18,000 patients with atrial fibrillation to understand how high blood pressure affects their health. The study revealed that there is a 50% risk for stroke in patients with atrial fibrillation and high blood pressure.
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