General causes

Atrial flutter/flicker can occur in all diseases of the heart that are associated with damage or overstretching of the atria. Diseases that often lead to atrial fibrillation: Multiple reentry circuits are considered the basic mechanism of atrial flutter/flicker. During normal cardiac action, any potential is lost once the ventricular muscles are reached, as they are then surrounded by tissue that is difficult or impossible to excite.

It is said that the tissue is refractory. The cells must first “recover” from the potential that has just passed. If the area of heart cells is damaged, the transmission of potentials can be slowed down.

However, this excitation can now pass through the damaged area in the opposite direction as it reaches it at a time when it may no longer be refractory. The danger here is that the excitation wave will re-enter the surrounding tissue when it is no longer refractory. An excitation can develop that is, so to speak, self-sustaining.

Heart failure (the heart does not have enough strength to pump all the blood out of the ventricles and atria, there is always a residue left. Thus, step by step a dilatation of e.g. the atria occurs)
Mitral valve disease (the mitral valve separates the left atrium from the left ventricle; if it is permeable, for example, blood is pumped into the atrium with each ventricular contraction, which is thus overstretched.
Metabolic disorders, e.g. hyperthyroidism

In atrial flutter, there is an unrhythmic contraction of the left and right atria of the heart, resulting in cardiac dysrhythmia.

Between the atria and the left and right chambers of the heart, there is a node in the stimulus transmission system that acts as a filter and transmits only every 2nd to 3rd impulse to the ventricles. This means that the atrium beats faster than the ventricle during atrial flutter. The AV node serves as a vital filter station.

If this station did not exist, the entire heart would start moving irregularly and too fast. The causes of atrial flutter vary, but usually indicate an underlying structural disease. Enlarged and coronary heart disease that goes untreated for a long time can lead to atrial flutter.

Elderly people in particular are affected by this stimulus transmission disorder. Often the detection of atrial flutter is a chance finding.The rapid contraction of the atria during atrial flutter can cause a heart rate in the atria of up to 150 beats per minute. A distinction is made between typical and atypical atrial flutter.

In typical atrial flutter, the impulses triggered by the irregular contraction of the atria are generated in the area of the atria, more precisely in the area of the so-called tricuspid valve. In atypical atrial flutter, the circular movements occur further away from the aforementioned heart valve. The distinction between typical and atypical atrial flutter is therefore based on the localization.

Symptoms and diagnostics of both types of flutter are the same. Sometimes it is not possible to find out what the actual cause is. Especially elderly people are affected by this cardiac transmission disorder.

In some rare cases, younger people are also diagnosed with atrial fibrillation or atrial flutter. In older people, heart enlargements due to poorly adjusted blood pressure are usually responsible. When the heart and its chambers enlarge, the atria, which are the conduits for the transmission of stimuli, also expand.

When these pathways are stretched, they become longer, resulting in a prolonged transmission of stimuli. While the first excitation still rolls over the heart muscle, the second excitation already begins, a condition that does not exist in normally sized atria. This results in the typical rapid, uncontrolled contraction of the atria.

Another important cause is coronary heart disease, i.e. a disease of the heart in which the blood vessels supplying the heart are too narrow and cannot pump enough oxygen into the heart muscle. Untreated CHD not only increases the risk of heart attack, but also increases the risk of atrial flutter or fibrillation. The smallest scars in the area of the cardiac transmission system are mainly responsible for atypical atrial flutter.

They are usually caused by small heart attacks that have occurred in the past and have not been noticed (silent attacks). Sometimes such scarring can be detected in the ECG, sometimes such scars can only be suspected as the cause. The difference between atrial fibrillation and atrial flutter lies in the frequency achieved and the typical ECG image. Atrial fibrillation is faster than atrial flutter, and the ECG does not show sawtooth-shaped P-waves during fibrillation, but irregular serrations.