The purpose of this study is to study the effects of transthoracic electrical cardioversion for restoration of sinus rhythm in patients who present with recent onset atrial fibrillation, with regard to new silent cerebral thrombo-embolic lesions and cognitive function, as well as electrical and functional/structural reverse remodelling, and its effects on inflammatory changes / specific cardiac biomarkers, vasoactive peptides, coagulation activity, and active fibrinolysis.