The main content of the electrocardiographic atlas "Arrhythmias and Heart Blocks" was made up of the authors' own observations, who for many years studied this most important problem at the Department of Cardiology of St. Petersburg MAPO (formerly Leningrad GIDUV). The new edition of Atlas reflects modern ideas about the mechanisms of arrhythmia and heart block formation, as well as new diagnostic criteria for various forms of heart rhythm and conduction disorders.