“Interference” in the heart: how atrial fibrillation affects heart function
A research team from Regensburg was able to deepen knowledge about the effects of atrial fibrillation on the entire heart. So far, research has focused on the consequences for the atria of the heart. The current study clarifies for the first time the impairments of the whole heart that can result from atrial fibrillation. As a result, a disturbed calcium balance is responsible for damage to the heart chambers.
A working group led by medical professor Dr. Samuel Sossalla of the University Hospital Regensburg receives the Wilhelm P. Winterstein Prize from the German Heart Foundation for new findings on how atrial fibrillation can affect the whole body. heart. The study was featured in the renowned journal "Circulation Research".
Findings shed new light on atrial fibrillation
According to the German Heart Foundation, the results of the current research shed completely new light on the processes that take place in atrial fibrillation. As a result, the whole heart can be affected by fibrillation.
For the first time, the latest findings provide insight into the effects atrial fibrillation can have on the ventricles of the heart. According to the researchers, the processes of the atrium in atrial fibrillation are quite well known.
"On the other hand, the effects of atrial fibrillation on the function of the heart chamber, the so-called ventricle, and thus on the heart as a whole, are not yet understood", emphasizes medical Dr. Steffen Pabel from the study team.
“The findings of Dr. Pabel and his team are of great importance for clinical research because they are the first to describe the harmful effects of atrial fibrillation on the human ventricle,” confirms medical professor Dr. Armin Welz, who is also Chairman of the Scientific Advisory Board of the German Heart Research Foundation.
Atrial fibrillation often associated with heart failure
In Germany, about 1.8 million people are affected by atrial fibrillation (AF) called non-tachycardia. This makes AF the most common form of cardiac arrhythmia. AF is often accompanied by heart failure, which affects around four million people in Germany.
Previous studies have already shown that therapy for atrial fibrillation can improve left ventricular function and reduce mortality, especially in people with the condition who also have heart failure.
course of the study
The team led by Pabel and Sossalla have now discovered why the ventricle can be damaged by AF. The researchers compared participants with a normal heart rhythm (sinus rhythm) to a group of subjects with atrial fibrillation. Among other things, heart muscle tissue from the left ventricle was analyzed for this purpose.
Atrial fibrillation was found to be rate controlled. This means that the heart rate was normal, but the heart rhythm was irregular. However, just like in people without AF, the team found no structural differences such as scar tissue in left ventricular heart muscle.
Calcium balance responsible for damage to the heart chambers
“However, we were able to determine in patients with atrial fibrillation that the calcium balance, important for the contraction of the heart muscle, was disturbed in the heart muscle cells, the cardiomyocytes, of the left heart chamber,” says Pabel.
In in vitro experiments, the team was able to confirm that artificially generated atrial fibrillation also alters calcium balance in heart muscle cells.
Irregular calcium intake in atrial fibrillation
Because an orderly inflow and outflow of calcium (Ca²+), sodium (Na+) and potassium (K+) is crucial for the proper functioning of heart muscle cells. Only a regular heartbeat ensures a constant supply of these nutrients.
The team explains the process in more detail: Each individual heart muscle cell is involved in the contraction and subsequent relaxation of the heart muscle. In order for the heart muscle to contract, a so-called action potential must first be built up, which spreads over the entire muscle tissue.
This action potential is built by a brief change in the state of electrical excitation in a muscle cell. This results in a displacement of the ions (Ca²+, Na+ and K+).
Ultimately, this chain reaction triggers the contraction, i.e. the heartbeat. Calcium or calcium ions (Ca²+) are decisive for the smooth running of the process.
Atrial fibrillation - a disease of the whole heart
“A reduced systolic calcium ion concentration in cardiac cells may therefore be associated with limited contractility of the heart and indicate dysfunction of the heart in the systole, the contraction phase,” Dr. Pabel summarizes together.
"Our findings on the adverse effects of atrial fibrillation on the ventricle should encourage physicians and scientists to understand atrial fibrillation not just as a disease of the atrium, but as a disease of the heart as a whole," summarizes the head of award-winning research. work. (vb)
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This text corresponds to the specifications of the specialized medical literature, medical guidelines and current studies and has been verified by health professionals.
Graduate editor (FH) Volker Blasek
Sources:Deutsche Herzstiftung: Interfering fire not only in the atrium: atrial fibrillation can damage the whole heart (published: 2022-06-18), herzstiftung.dePabel S. et al, Effects of atrial fibrillation on the human ventricle; in: Circulation Research (2022), doi.org
This article contains general advice only and should not be used for self-diagnosis or treatment. It cannot substitute a visit to the doctor.