What With an aging population the number of persons with atrial fibrillation rises. Atrial fibrillation increases the risk of stroke, heart failure and mortality. It is therefore a major economic burden to the society and impacts people’s quality of life. Understanding the basic mechanism that occurs in the heart will help to uncover new drug targets, which will benefit the patients and drive the development of new drugs. Why Atrial fibrillation is the most common heart rhythm disturbance, affecting 2% of the population. I will clarify how the electrical signals of the heart changes during the disease, and if these changes are reversible. How My approach is based on novel experimental models and biopsies from patients. Using pharmacological tools, electrophysiological and molecular biological techniques I will study the electrical changes that occurs in atrial fibrillation and if they are reversed upon treatment.