Cardiovascular diseases (CVD) remain one of the most common causes of mortality and disability among the working population both in Ukraine and throughout the world. Early detection, effective primary and secondary prevention of CVD can prevent these complications. The purpose of our investigation was to study the effectiveness and safety of the combined potassium and magnesium drug in the complex treatment of patients with atherosclerotic coronary artery disease, heart rhythm disorders and chronic heart failure. 80 patients included in the study were diagnosed with stable angina of II-IV functional class), heart rhythm disorders (supraventricular and ventricular extrasystoles) and chronic heart failure (II-III NYHA functional class and all of them were divided into two groups. The main group included 40 patients who, as part of a complex treatment including antiplatelet therapy, beta-blocker, an ACE inhibitor, and a statin, additionally received a combined potassium and magnesium drug (10 ml per day intravenously) for 12-14 days. The control group, which consisted of 40 patients, received only pathogenetic therapy. It was established that the use of a combination of potassium and magnesium as a part of the complex treatment of patients with atherosclerotic coronary artery disease, heart rhythm disorders and chronic heart failure contributed to improvement of the quality of life of the patients, reducing the number and duration of anginal attacks, reducing the need for short-acting nitrates, increasing the distance of the 6-minute walking test, improvement of the functional class of chronic heart failure. Taking the drug did not lead to the development of side effects requiring it withdrawal.