Newly identified gene may open route to innovative treatments for atrial fibrillation
Atrial fibrillation is a cardiac arrhythmia - a chronic irregularity of heartbeat - which affects an estimated 1 million people in Germany. Although the condition is not acutely life-threatening, it does increase the risk of developing more serious illnesses, such as cardiac insufficiency, stroke and dementia. In the third of a series of genomewide asssociation studies, an international team of researchers, led by LMU physician PD Dr. Stefan K--b, now reports the identification of a new gene locus that has a significant influence on risk for atrial fibrillation. The product of this gene is a so-called potassium channel, which plays a role in coordinating the electrical impulses that control heartbeat. "The discovery of this functional link will enable us to develop new and more specific drugs for the treatment of atrial fibrillation", explains K--b. The discovery is the result of a meta-analysis of data from ten large-scale epidemiological studies, and emerged from a comparison between the genomes of 1335 patients with atrial fibrillation and those of 12844 healthy control subjects. The analysis was carried out in close collaboration with scientists at the Technical University of Munich and the Helmholtz Center Munich, with contributions from over 50 other international research institutions. (Nature Genetics online, 21 February 2010)
In order to transport blood efficiently through the vascular system and ensure that all vital organs receive an adequate supply, the heart must function in a highly coordinated fashion. Contractions of the atrium and the ventricles must occur in the correct sequence and in the right temporal relationship to each other. This process is controlled by the coordinate generation and conduction of electrical signals, which are initiated by the sinus node and can be recorded on electrocardiograms. Cardiac arrhythmias arise when the sinus node is unable to perform this task adequately. Atrial fibrillation is a milder form of arrhythmia than ventricular fibrillation and does not pose an acute threat. But as LMU's PD Dr. Stefan K--b points out, "Atrial fibrillation can give rise to more serious conditions - principally as a result of the fact that the blood is not completely expelled from the heart, and this facilitates the formation of thromboses. These, in turn, can precipitate strokes or an embolism - the complete obstruction of a blood vessel. Atrial fibrillation also increases the risk of cardiac insufficiency, which may result in reduction of brain function and, ultimately, dementia."