Isolated left ventricular non-compaction (LVNC) is a rare variant of unclassifiable cardiomyopathy (CMP). The basis of the clinical picture of non-compaction CMP is heart failure, arrhythmias, and thromboembolism. Acute cardiac and extracardiac diseases can act as a trigger for the LVNC manifestation. The paper provides an example of diagnosing LVNC in an adult patient after acute myocarditis against the background of vaccination against a new coronavirus infection COVID-19. The characteristics of the ongoing therapy are given and the dynamics of the course of the disease over a period of five months of observation is reflected.