The heart is a busy muscle: it normally beats evenly, day or night, whether we are resting or exerting ourselves, when running or sleeping. It produces around 70 beats every minute in an adult at rest. During this time, it pumps five liters of blood through the body and ensures that all organs are supplied with oxygen.
Conductor is the sinus node. It consists of special muscle cells and is located in the right atrium. It triggers the heartbeats with electrical impulses. “This sinus rhythm can get out of sync if the impulses are not sent properly or there are problems in transmitting them to the atria and ventricles,” explains Prof. Dr. Thomas Arentz, Head of the Department of Rhythmology at the Clinic for Cardiology and Angiology II of the University Hospital Freiburg. “Then we’re talking about a cardiac arrhythmia.”
Tachycardia is a heartbeat that is too rapid or a racing heart when you are resting, often accompanied by shortness of breath or chest pain. In bradycardia, on the other hand, a heartbeat that is too slow can lead to dizziness, tiredness and light-headedness. Atrial fibrillation is one of the most common cardiac arrhythmias: the atria generate a persistently irregular, often rapid pulse. “Cardiac arrhythmias are rarely acutely dangerous. However, disorders that originate in the main chambers of the heart often have to be treated immediately,” says Arentz. “So anyone who feels their heart is out of rhythm should seek medical advice.”
Electrophysiology: Precise diagnostics and targeted therapy
A heart that is beating irregularly can be treated in different ways. The classic way is medication. “It is far more promising to identify the area in the heart that causes the disorder,” says PD Dr. Amir Jadidi, Senior Physician in the Rhythmology Department of the Clinic for Cardiology and Angiology II. An electrophysiological examination (EPU) is carried out for this purpose. The cardiac currents are diverted to various points on the inner wall of the heart via a venous access in the groin. From this, a precise diagnosis can often be made and appropriate therapy can be initiated. “In the case of tachycardia, for example, the area responsible can be sclerosed directly during the examination using a catheter,” explains Jadidi. For effective therapy of the most common cardiac arrhythmia in humans – atrial fibrillation – the pulmonary veins responsible for this are electrically isolated by catheter ablation in order to eliminate these sources of arrhythmia and restore normal sinus rhythm. “If the heart beats too slowly, a pacemaker usually helps to maintain a healthy rhythm.”