Introduction
During the last year the world has faced a new Corona virus pandemic, named COVID-19. Although COVID-19 clinical manifestations are mainly respiratory, cardiac involvement exists in a substantial number of patients, and cardiac arrhythmias have been reported in variable percent of patients, ranging from 6% to 19% of overall hospitalized COVID patients and from 9% to 44% of COVID patients hospitalized in intensive care units (ICU).1,2,3 In some patients, arrhythmias represent the first clinical manifestation of COVID infection,4,5 while in others arrhythmia may occur only during the recovery out-of-hospital period.6Overall, there seems to be a correlation between disease severity in general and cardiac involvement specifically to occurrence of cardiac arrhythmias,2,4,6 although sudden cardiac death was described among mild COVID-19 patients as well.4Moreover, a significant minority of severe COVID ICU patients with arrhythmias had normal troponin levels, suggesting other mechanisms rather than cardiac injury, triggering arrhythmias in these patients.3,7 Various potential causes for cardiac involvement and arrhythmias were suggested, including: a) direct viral myocardial injury- myocarditis,2,4,6 b) cytokine-induced myocardial injury as well as cytokine-mediated conduction disturbances8,9 and QT prolongation;3 c) hypoxemia, d) hypotension, e) hyper-adrenergic state, f) drug effect, such as hydroxychloroquine or azithromycin , which can lead to prolonged QT-related Torsades de Pointes as well as to nodal and infra-nodal conduction disturbances.4,10,11 Although much data has accumulated regarding various cardiac complications in COVID-19, the characterization and exact prevalence of cardiac arrhythmias among COVID-19 patients and more so among the mild-moderate ones is still unclear.4,6 Furthermore, although various possible predictors for cardiac arrhythmias in COVID patients were speculated,2,4,6,7,9 a simple clinical algorithm to classify arrhythmic risk has not been developed so far. Such algorithm is critical to guide cardiac monitoring level during the hospitalization period and maybe during the recovery period as well. The primary aim of our study was to characterize the various arrhythmias encountered among hospitalized COVID-19 patients of various severity levels, describe their prevalence and develop a clinical algorithm to classify arrhythmic risk.