Dilated cardiomyopathy (DCM) is a severe myocardial disease characterized by marked dilation of the left ventricle or both ventricles and progressive heart failure. It is one of the leading indications for heart transplantation worldwide. The etiology of DCM is heterogeneous and includes both genetic predisposition and external factors, among which previous viral myocarditis plays a key role. However, establishing the exact etiology remains challenging, because verification of viral myocardial injury in routine clinical practice is associated with objective difficulties. This article presents two clinical cases of severe DCM in young patients after an acute respiratory viral infection. The development of end-stage heart failure refractory to medical therapy required advanced treatment modalities: heart transplantation was recommended for one patient, whereas the other underwent implantation of a cardiac contractility modulation (CCM) system. In addition, the disease course in the first patient was complicated by thromboembolism of segmental branches of the pulmonary arteries in both lungs. Maintaining a high level of clinical vigilance in patients presenting with nonspecific complaints such as dyspnea, weakness, pain, and chest discomfort after an acute respiratory viral infection is critically important, as early diagnosis and timely initiation of pathogenetic therapy for myocarditis may prevent structural myocardial changes and, consequently, irreversible dilation of the cardiac chambers.