ACE2 and cardiac arrhythmia: In this review, we address COVID-19 concerns for the cardiologist and electrophysiologist, including arrhythmia and conduction abnormalities, myocarditis, and arrhythmia in critically ill patients; angiotensin-converting enzyme 2 in cardiac patients; hypercoagulability; and the drug properties of hydroxychloroquine as one of the potential therapies under review.