Arrhythmic shock (AS) results primarily from many types of tachyarrhythmias: atrial fibrillation and flutter, supraventricular tachyarrhythmias, ventricular paroxysmal tachycardias. AS is distinguished from the stable course of the above arrhythmias by pronounced changes in central hemodynamics (CH) and by rapid and frequently negative manifestations. The status of CH is an important criterion when whether electrical cardioversion is performed is decided. CH was studied in 306 patients with genuine cardiogenic shock and in 32 patients with AS. In case of effective cardioversion, central hemodynamics in patients with AS underwent rapid changes: first of all, stroke volume and cardiac index increased and end systolic volume decreased. In case of effective of antishock measures, CH in patients with cardiogenic shock normalized only within 3-4 weeks of their stay at an intensive care unit, but ejection fraction also remained decreased at their discharge from hospital.