Fast facts about Atrial Fibrillation

AN ESTIMATED 2.7 million Americans are living with atrial fibrillation. Though no census is done, Filipino cardiologists are unanimous in saying that indeed, atrial fibrillation is the most common arrhythmia (heart beat irregularity) among elderlies 60 years old and above. AF itself is not life-threatening, unlike the much-dreaded ventricular fibrillation, which for the most part, serious and fatal. Be that as it may, still atrial fibrillation merits attention and concern from care givers. The good news is that AF can be treated and controlled.

Let's take a brief look at atrial fibrillation. With AF, the heart's electrical impulses lose their regular rhythm so the contraction of the heart is irregular. The impulse no longer comes from the sinus node (the so-called big boss in controlling heart rate and rhythm). Instead, other parts of the atria (the receiving chambers of the heart) become the origin of the electrical impulse, so that the heart beat is irregular. During AF, the impulses are very rapid (more than 300 beats per minute) and uneven. In response to these impulses, the atria contract quickly and unevenly leading to an erratic, unpredictable amount of blood ejected from the heart. Another way of putting it is, during AF, the atria quiver like a bowl of gelatin, instead of pumping rhythmically and forcefully. Sometimes, rapid AF impulses cross to the ventricles which cause them to beat rapid and irregularly as well. However the ventricular rate is much slower than the atrial rate, which usually ranges from 120 to 160 beats per minute.

During AF, some blood may not be pumped from the atria to the ventricles efficiently because as we have said earlier is quivering like a bowl of gelatin, instead of pumping forcefully and rhythmically. As a result, the blood that is left behind can pool and collect in the atria to form blood clots. Now, if a blood clot leaves the heart and enters the blood stream, it can travel to your brain, block an artery or blood vessel and cause a stroke. The risk of stroke is about five times higher in people with atrial fibrillation. Your chances of having a stroke are even higher even if you're over 65.

Often, the cause of AF is unknown. But certain factors can make you more likely to develop it. AF often affects people with coronary heart disease (obstruction or blockade of blood vessels supplying oxygen to the heart) or tose who just had a heart attack. Of course, don’t forget the fact that AF is more common among people with high blood pressure, recent heart surgery, rheumatic heart disease, inflammation of the heart (yocarditis- viruses being common causes) or inflammation of the covering of the heart (pericarditis), congenital heart disease, an overactive thyroid gland or an acute or chronic lung diseases. Diabetes, excessive alcohol intake and stimulant drugs increase the risk of atrial fibrillation .

Next Week: Symptoms and treatment of Atrial Fibrillation