This is a single center, open-label, randomized, crossover study. Subjects will be admitted to the cardiology department on the day before the first dose and will remain there until study completion. After performing a baseline electrocardiogram and baseline blood tests (Complete Blood Count, chemistry - up to 10 ml of blood) subjects will be continuously recorded by a Holter monitor for 24 hours (baseline Holter). On the next day subjects will be randomly divided into two experimental therapies (one after the other in a random order to the same group of patients