The specialists in the practice clinic for Diagnostics and Preventive Medicine in Bornheim near Cologne and Bonn have been working intensively for many years on Diagnosis and therapy of atrial fibrillation.
For many patients, atrial fibrillation means an increased risk of Stroke.
A particular danger: Around 70% of atrial fibrillation attacks are not even noticed by the patients.
The symptoms are often non-specific: sudden loss of performance, tiredness, palpitations or sleep disorders occur. Many people who suffer from atrial fibrillation are not even aware of this.
"The extent to which atrial fibrillation causes symptoms is of crucial importance when it comes to the question of the necessary treatment of atrial fibrillation," says Dr. Lunow, medical director of the Bornheim practice clinic, and refers to the classification of the "European Heart Rhythm Association" (EHRA). "EHRA1 are patients without symptoms, EHRA2 patients have mild symptoms that do not affect their age-related activity, EHRA3 patients have pronounced symptoms that impair their daily activities, and EHRA4 patients have symptoms that make normal daily activities impossible."
Normally, the sinus node in the right atrium regularly sends out electrical impulses, causing the heart muscles to contract.
During these contractions, the blood is pumped from the atria into the ventricles and from there into the vessels. In atrial fibrillation, however, the electrical impulses circulate in the atria at up to 500 impulses per minute. The heart muscle then fibrillates, regular contractions no longer occur, and the blood remains in the atria where it can clot.
An overactive thyroid or a Hypertension and other heart diseases increase the risk of developing atrial fibrillation. trigger Alcohol and nicotine consumption are also considered to be a risk factor. It is estimated that in the future, around one in four people aged 40 today will develop atrial fibrillation in later life.
Rhythm disorder causes blood clots
The main danger of atrial fibrillation is that the risk of stroke can increase significantly due to the formation of blood clots in the atrium. For this reason, after assessing the individual risk, a decision is made as to whether anticoagulant medication such as Marcumar or aspirin must be taken. These medications, also known colloquially as "blood thinners", are intended to prevent the formation of clots in the fibrillating atrium and thus reduce the risk of stroke.
“We use the so-called CHA2DS2-VASc score to assess the risk of stroke in atrial fibrillation,” explains Dr. Lunow.
“If there is a heart failure, high blood pressure, Diabetes mellitus, a previous heart attack or a circulatory disorder of the leg vessels, at an age of 65-74 and if female, the patient receives one point. Over 75 years and with a previous stroke, Embolism or in the case of temporary circulatory disturbances in the brain, 2 points are awarded in each case."
If this score is 2 points or more, treatment with Marcumar is indicated. The so-called INR value should be between 2,0 and 3,0. If the total score is only 1 point, acetylsalicylic acid (e.g. aspirin) can be given as an alternative at a dosage of 75 to 300 mg.
(Image: Gerd Altmann/pixelio.de)On average, patients with atrial fibrillation without Marcumar or ASA therapy have an annual risk of about 6% of suffering a stroke. This risk can be reduced to about 2,7% per year with therapy with Marcumar.
At the same time, it is important to weigh up the risk of blood thinning against that of severe bleeding.
The HAS-BLED score helps with this. Points are also awarded here: one point each for high blood pressure, impaired kidney or liver function, stroke, previous bleeding, fluctuating INR values, age over 65, chronic medication use or heavy alcohol consumption. From three points onwards there is a greatly increased risk of bleeding. Long-term blood-thinning medication is particularly dangerous for these patients.
cardioversion for atrial fibrillation
In addition to reducing the risk of thrombosis, the focus is also on eliminating atrial fibrillation.
One way to do this is electrical DC cardioversion, i.e. an electric shock under short anesthesia. This involves an electric shock being delivered to the heart in order to synchronize the muscle cells, i.e. to create an orderly activity starting from the sinus node. This type of cardioversion has a success rate of around 90%. Such an electric shock is the method of choice in an emergency in the event of circulatory collapse or when drug-based cardioversion has not been successful.
Cardioversion without prior examination of the atrium for existing thrombi can only be performed if atrial fibrillation does not last longer than 48 hours.
If it has persisted for more than two days, either an ultrasound examination of the heart in the form of a so-called transesophageal Echocardiography (TEE) is necessary, or the blood must be thinned with medication for three weeks. Low molecular weight heparin (thrombosis injection) can also be used here. After cardioversion, the blood thinner must be taken for another four weeks, as the mechanical activity of the atrium often only returns to normal after this period.
Cardioversion can also be achieved with medication. The active ingredient flecainide (e.g. Tambocor) can be used to convert atrial fibrillation into sinus rhythm by taking tablets. This medication should not be given in the case of "structural heart disease". Alternatively, propafenone (Rytmonorm) 450-600 mg can be given. This medication is also contraindicated in the case of structural heart disease or QT prolongation. Unfortunately, all medications can eliminate the arrhythmia and can also trigger arrhythmias.
Ablation has established itself as a new form of therapy in recent years.
However, this is a highly invasive operation. In over 90% of patients with atrial fibrillation, the interference pulses come from the tissue at the junction of the veins in the left atrium. To prevent misfiring, a catheter is pushed through the femoral vein into the atrium and the tissue in the area of the interference is heated and thus destroyed.
This operation takes about 2-3 hours, and the hospital stay is usually only 2-3 days. Unfortunately, the complication rate of this ablation operation is about 3%. However, the heat can cause a hole in the heart wall, damage the esophagus, or even cause a blood clot to form during the operation. About 70% of patients without other heart disease are cured after the first operation. If the patients are older or have other heart diseases, the success rate drops to less than 50%. If the atrial fibrillation recurs after 3-5 months, another operation is necessary.
Rate control as an alternative to cardioversion
"If it is not possible to eliminate the atrial fibrillation and restore a sinus rhythm, frequency control is definitely a good idea," advises Dr. Lunow. Medication ensures that the heart does not beat more than 100/min. Calcium antagonists such as verapamil or diltiazem, beta blockers or digitalis can be given. Sometimes it is also necessary to combine these medications.
New blood-thinning drugs
As an alternative to Marcumar, the drug Dabigatran (trade name Pradaxa) can be given at 2x150 mg/day. With Pradaxa, there are about 1,1% strokes per year, with Marcumar 1,69%. The bleeding rate with Marcumar is 3,3% per year, with Pradaxa 3,1% per year. "A big problem is that this drug cannot be given in cases of renal insufficiency, as there is a risk of severe bleeding," warns Dr. Lunow. For this reason, renal function should definitely be checked before starting treatment. If the creatinine clearance is below 30 ml/min, Dabigatran must not be given.
Since December 2011, another new blood thinning drug has been on the German market: Rivaroxaban (Xarelto). This drug is approved for stroke prevention in cases of atrial fibrillation that is not caused by a heart valve defect, and for the prophylaxis of deep vein thrombosis and pulmonary embolism. Xarelto is taken as a tablet. It reduces coagulation as a so-called factor Xa inhibitor.
“In any case, even non-specific impairments should be taken seriously and Doctor Only in this way can atrial fibrillation be detected and the appropriate measures taken," warns Dr. Lunow and recommends regular preventive examinations.
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