Atrial fibrillation
Atrila fibrillation is the most common and complex type of cardiac arrhythmia. It is a widespread disease with increasing prevalence, and the number of patients increases with rising age. In Germany alone approx. 800,000 people suffer from atrial fibrillation. It is estimated that in 40 years time more than 2.5 million people will be affected. Globally more than 13.5 million people suffer from atrial fibrillation.
The fact that improved medical care leads to people living longer also contributes to the expectation of an increase in patient numbers. In people over the age of 85 the prevalence of atrial fibrillation is 10% (1). On average, one in 50 people suffers from atrial fibrillation (2%). It is expected that the number of patients will have increased to 28 million in 2050 (2,3). This means that for many people the risk of serious consequential illnesses such as stroke, thrombosis, embolism, bleeding and organ failure is also increasing. The risk of an ischaemic attack with atrial fibrillation is even 5 times higher than normal.
Atrial fibrillation means that patients are on life-long medication, which can have serious side-effects.
(1) Acc. to the study "Prevalence of diagnosed atrial fibrillation in adults: national implications for rhythm management and stroke prevention: the AnTicoagulation and Risk Factors in Atrial Fibrillation" (Jama 2001; 285: 2370-5) by Hyek, Phillips et al.
(2) Jama 2001; 18: 2370;
(3) The EHRA Whitebook 2009
How is atrial fibrillation noticed?
The heart has lost its rhythm completely, and the heart beats follow one after the other in a chaotic fashion. Sometimes the heart is racing with up to 160 beats per minute, whereas in other cases it slows down too much. Frequently the results of a racing heart are inner restlessness, anxiety, sweating, breathlessness and reduced physical performance, but many patients do not show any symptoms at all, and their atrial fibrillation is discovered accidentally by the doctor.
What happens inside the heart with atrial fibrillation?
In the atria, electrical excitation waves circulate, which lead to an atrial frequency of up to 350 beats per minute. The atria are no longer able to contract, neither are they involved any longer in the heart's pumping performance. The pumping of the heart now only happens via the heart chambers, which results in irregular blood flows. The blood flow in the atrium slows down and the build-up of blood clots is more likely.
How does atrial fibrillation develop?
Atrial fibrillation is caused by interfering electrical pulses. These frequently originate in the cell groups of the lung veins (pulmonary veins) and, independently from the electrical heart excitation, emit electrical signals, which disturb the normal excitation spreading in the left atrium. This leads to a chaotically spreading electrical activity, combined with an accelerated or decelerated frequency in the heart chamber. This way, an effective contraction of the cardiac muscle is prevented. Circulating excitation waves in the atrium itself maintain the atrial fibrillation.
Which causes favour atrial fibrillation?
The following causes can lead to atrial fibrillation:
- Heart valve diseases
- Rheumatic heart diseases
- Cardiac muscle diseases/inflammations
- High blood pressure
- Pulmonary embolism
- Hyperthyroidism (mostly in younger patients)
- Alcohol and medication abuse
In many cases no cause is diagnosed at all, in which case the condition is called idiopathic atrial fibrillation.
What are the consequences of atrial fibrillation?
Depending on the heart's overall state, atrial fibrillation can cause minor complaints, but also lead to serious secondary illnesses. Due to the irregular blood flow in the atrium there is an increased risk that blood clots might form, which then move to other organs and to the brain in the form of embolisms, where they may cause a stroke. More than 15% of all strokes happen with atrial fibrillation, resulting to more than 40,000 cases in Germany alone.
What are the treatment options?
Medication has shown insufficient success
Therapy by means of medication can be administered in two ways. On the one hand, blood thinning (anticoagulation) can prevent blood clotting and thereby lower the risk of embolisms. On the other hand, antiarrythmics can be used for regulating the heart rhythm. However, this therapy does not necessarily heal the condition once and for all, and the permanent taking of some drugs promotes serious side effects.
In most cases cardioversion is not permanently effective
In order to bring the heart activity back to its normal rhythm, the synchronised cardioversion administers a brief electric shock, which is given to the heart under a short-term anaesthetic, "to bring the heart back to zero" and create a normal heart rhythm. This treatment does not lead to permanent skin damage. However, after a while the atrial fibrillation frequently reappears.
Catheter ablation is treating the root cause
The catheter ablation is a minimally invasive operation, which is carried out under a local anaesthetic. A 2-3 mm thick tube, the catheter, is inserted into the heart via the femoral vein. From the tip of the catheter, an energy pulse (high-frequency current or laser) is emitted in order to make point-shaped or line-shaped atrophy scars. The close proximity of many small atrophy points or line-shaped atrophies results in a continuous scar line, which separates the interference pulses from the pulmonary veins from the left atrium. This way the spreading of the electrical interference pulses into the left atrium is prevented and the atrial fibrillation is successfully cured – with minimum risk and without the need for permanent medication.
The catheter ablation using a laser does not remove the symptoms but the causes. In the majority of cases the treatment is successful and only needs to be given once. It stops the electrical pulses, which originate from the pulmonary veins and are handed on from cell to cell inside the cardiac muscle.
