What is atrial fibrillation ?
Atrial fibrillation, in Belgium also known as atrial fibrillation, a heart arrhythmia in which the upper chambers (atria) of the heart does not contract as normal after a discharge from the sinus node but many contract rapidly and irregularly. The heart remains (in contrast to ventricular fibrillation) or retain a large part of the pumping function vital because the rooms are still work effectively, but in an irregular rhythm.
Atrial fibrillation causes
The most common causes of atrial fibrillation are high blood pressure, a heart valve dysfunction -and especially mitraliskleplekkage- and reduced pumping function of the heart. The underlying mechanism is based in all these cases probably on dilation of the left or right atrium. Also other cardiac or non-cardiac causes that lead to enlargement of the atria are associated with atrial fibrillation. Occasionally, there is a non-cardiac cause such as hyperthyroidism. Moreover, often find no cause, then one speaks of "lone atrial fibrillation". Atrial fibrillation is mainly a disease of old age, with increasing age, the risk of atrial fibrillation significantly. Under 65 years only 1 to 2% of people atrial fibrillation. At 80 years of age or older, the incidence rises to around 20%. This disorder is common (about 15% of Dutch people over 65 years).
Atrial fibrillation symptoms
Atrial fibrillation is noticeable by an irregular, often rapid heart rate and a decrease in the pumping function of about 20-30%, so the patient is rather short of breath. The atria squeeze no more organized together but the contraction of the muscle fibers is purely chaotic, causing the blood no longer active the ventricles is pumped. As a result, the blood can come to a stop in the heart chambers, which can result in blood clots in the atria. Usually arise these blood clots in the appendage of the left atrium. Blood clots can embolize, or come loose and be carried through the bloodstream. They may then get stuck elsewhere in the body and result in a vascular occlusion. Usually, to embolize the blood clots to the brains causing a stroke. When fast heart rhythms sometimes occurs angina as a result of lack of oxygen in the heart muscle.
Atrial fibrillation treatment (Drug treatment)
Since atrial fibrillation at the risk of the formation of clots in the atria is elevated, often anticoagulants are prescribed in order to prevent these blood clots, and thus also the risk of embolization of such clots. When embolization hits the clot out of the heart into the blood circulation, and can then, for example, cause a stroke.
The probability of clot formation, and so on a stroke, is mainly determined by additional factors. These additional factors include age> 65 years, structural heart abnormalities (such as poor pumping function, mitral regurgitation, left ventricular hypertrophy), hypertension, diabetes mellitus. The risk of stroke in atrial fibrillation can be calculated with the aid of the CHA2DS2-Vasc score. The higher the score, the higher the risk of getting a stroke. The outcome of this score, or direct thrombin inhibitors, such as dabigatran (Pradaxa), coumarin derivatives such as warfarin (warfarin) or phenprocoumon (warfarin) should be used or the antiplatelet agent aspirin. In a CHA2DS2-Vasc score of 2 or higher are prescribed coumarin derivatives or direct thrombin inhibitors, with a score of 0 or 1, it is sufficient with acetylsalicylic acid. Of course, the bleeding risk is also taken into consideration.
Previously they only gave anticoagulants with persistent atrial fibrillation, nowadays with paroxysmal atrial fibrillation because it appears that even then there is an increased risk of clot formation.
Sometimes it is possible to restore a normal rhythm (this is called cardioversion and may be chemically or electrically happen), sometimes the atrial fibrillation has to be accepted, for example, if after repeated cardioversion the atrial fibrillation nevertheless always returns after a while comes on again, even if medicines are used to try to prevent this. If it is decided to accept the atrial fibrillation, it is usually necessary to slow the heart rate, this is done by slowing the conduction between the atria and ventricles via the AV node. For this purpose, there is a large number of drugs. Nowadays often used beta blockers such as metoprolol, or calcium channel blockers, such as verapamil or diltiazem. Less often nowadays given digoxin, since this particular effort to not work as well.
Treatment for atrial fibrillation (Non-drug treatment)
Fens lung isolation in relatively young people, so people younger than 65 years, without structural heart disease, it is sometimes possible through a catheter ablation to treat atrial fibrillation. This works best with paroxysmal atrial fibrillation, and when the atria are not enlarged. With such a catheter ablation are inserted via the femoral vein of one or more catheters that are shifted through the inferior vena cava (inferior vena cava) to the heart. Then, using a Brockenbrough needle puncture performed by the septum between the right and the left atrium. This is called a transseptal puncture. As a result, a special ablation catheter may then be slid into the left atrium. With this ablation catheter can be done using radio-frequency energy to be applied around the scars inmonding of the pulmonary veins. The intention with this is the scarring of the lung veins inmonding electrically insulate the atria. The rationale behind this is that this area often plays a role in the development of, in particular paroxysmal, atrial fibrillation. The success rate of this procedure is approximately 70-80% during a follow-up of 2 years. What the long-term results are not yet known. The major complications of this procedure are: a bleeding of the inguinal arteries, an arteriovenous shunt between the two groin wires, one cardiac tamponade (1%), a cerebrovascular accident (0.5%) and very rarely a connection between the left atrium and the behind located esophagus (an atrio-esophageal fistula).