Arrhythmias

A healthy heart beats about 60 to 100 times per minute in a regular rhythm. If the heart beats irregularly, too fast or too slow, this is called arrhythmia. Arrhythmias are among the most common heart diseases. In recent years, arrhythmias have become more and more frequent and the number of people who have died of them has also been steadily increasing.

Clinical picture

There are different forms of cardiac arrhythmias, which are distinguished by the speed of heart rate they cause: bradycardic arrhythmias with too slow heartbeat (less than 60 beats per minute) and tachycardic arrhythmias with too fast heartbeat (more than 100 beats per minute). Frequently, additional heartbeats occur, called extrasystoles, which are felt like "heart stumbling" and are usually harmless. Atrial fibrillation is the most common cardiac arrhythmia in Germany, affecting about 1 percent of the population (about 800,000 people).

The first signs of cardiac arrhythmia can be fatigue or dullness during normal, habitual activities. Other possible symptoms include heart stumbling, a racing heartbeat, dizziness, light-headedness, confusion, fainting, short-term loss of consciousness, seizures, chest pain or angina. The most important examination to diagnose cardiac arrhythmia is the electrocardiogram (ECG). This is used to record heart activity under resting and stress conditions and over a longer period of time (24 hours). Possible complications of cardiac arrhythmia include embolism, stroke, heart attack or increasing heart failure. After all, a quarter of all strokes are caused by atrial fibrillation. Taking blood thinning medications in time can reduce the risk of stroke by 70 percent.

Causes

Cardiac arrhythmias are most frequently caused by other, already existing heart diseases, such as coronary heart disease (CHD), heart attack, inflammation of the heart muscle, heart valve defects, heart failure or congenital heart defects. More rarely, diseases such as hyperthyroidism, severe lung diseases or disorders of the mineral balance are the cause. Some medications, excessive consumption of alcohol or coffee and severe stress or mental strain can also upset the heartbeat. Studies show that atrial fibrillation occurs more frequently with increasing noise exposure. Noise exposure at night has a greater effect on the heart rhythm than during the day.

Therapy

The treatment depends on the type of cardiac dysrhythmia and a possible underlying other (cardiac) disease. The so-called antiarrhythmics are used for drug treatment, in some cases in combination with anticoagulants. Some patients with atrial fibrillation cannot take anticoagulants because of the risk of bleeding. An alternative in such cases is to close the left ear of the heart with a kind of mini-screen. This is because more than 90 percent of blood clots form in the left atrial appendage, a sac in the left atrium of the human heart. From there, the clots can enter the blood vessels of the brain and trigger a stroke. The DZHK study CLOSURE-AF-DZHK16 examines how well the closure of the left atrial appendage is suited for patients with atrial fibrillation who are at high risk of bleeding and stroke.

Not all forms of cardiac dysrhythmia respond to medication. A pacemaker or a so-called cardioverter defibrillator (ICD) can help. A pacemaker regularly sends out electrical impulses and thereby sets the rhythm for the heart. An ICD looks similar to a pacemaker and is also implanted. It detects threatening rhythm disturbances and stops them by means of electrical impulses, which can prevent sudden cardiac death. Catheter ablation is another treatment option, especially in the case of atrial fibrillation, which is used to a small spot of diseased tissue in the heart.

DZHK studies on cardiac arrhythmias

CLOSURE-AF-DZHK16 – Left atrial appendage CLOSURE in patients with Atrial Fibrillation at high risk of stroke and bleeding compared to medical therapy
APPROACH-ACS-AF-DZHK7 – Apixaban versus Phenprocoumon: oral anticoagulation plus antiplatelet therapy in patients with acute coronary syndrome and atrial fibrillation
SCREEN AF-DZHK15 – Home-Based Screening for Early Detection of Atrial Fibrillation in Primary Care Patients Aged 75 Years and Older