Arrhythmias in pericardial syndromes have been poorly investigated and available data are mainly obtained from relevant studies however having different endpoints from arrhythmias. Thus, the incidence and prevalence of any type of arrhythmias may be actually higher than generally considered. Atrial arrhythmias, mainly atrial fibrillation and flutter have been reported as the most common rhythm disturbances in the setting of acute pericarditis. Concerning pathophysiology of atrial arrhythmias, in contrast to earlier hypothesis that they occur exclusively in the presence of an underlying structural heart disease, recent data support an arrhythmogenic potential of acute pericardial inflammation regardless of the presence of heart disease. In cases of myopericarditis, namely primarily pericarditis with evidence of myocardial involvement (i.e., troponin elevation without however overt left ventricular dysfunction and/or segmental wall motion abnormalities), ventricular arrhythmias appear to prevail. With reference to the rest of pericardial syndromes data on arrhythmias development are even more sparce. In particular, in constrictive pericarditis atrial tachyarrhythmias are the most commonly detected and seem to be related to disease severity and possibly to the underlying etiology. In this review we have summarized the available information on the incidence and prevalence of arrhythmias in pericardial syndromes. We wish to emphasize that the clinical significance of arrhythmias in this setting in terms of prognosis and optimal medical treatment (including need and safety of anticoagulation in atrial fibrillation/flutter complicating acute pericarditis), should be further investigated.