Atrial fibrillation (AT) is the most frequent type of arrhythmia in clinical practice. It causes a high rate of morbidity and mortality. A patient with known AF who follows adequate therapy and starts feeling dizzy, should alert his/her GP. An electrocardiogram is essential for correct diagnosis the presence of bradycardia in a patient with AF. This clinical situation constitutes a non-delayable reason to refer the patient to the hospital in order to carry out an etiologic study and adequate therapy because of the seriousness of this clinical picture (AU)