Cardiomyopathies are myocardial diseases characterized by structural and functional abnormalities of the heart muscle with complex etiopathogenesis. They can lead to the development of acute and chronic heart failure, malignant arrhythmias, the formation of thrombus and thromboembolic events, and sudden cardiac death. Despite extensive efforts of the medical community, cardiomyopathies are still very difficult to classify due to significant phenotypic and genotypic overlap between different forms of the disease. Traditionally, they are classified into hypertrophic, dilated, and restrictive cardiomyopathy. In 1990, Jonathan and Christine Seidman discovered the first mutation in the MYH7 gene associated with the development of hypertrophic cardiomyopathy (HCM), marking the beginning of research into the complex genetic basis of cardiomyopathies. For many years, the analysis of the genetic background of these diseases was limited by expensive and time-consuming methods. The discovery of next-generation sequencing (NGS) has enabled faster, cheaper, and more extensive testing. Genetic testing is conducted in patients with a confirmed diagnosis, those suspected of having the disease, and family members and relatives of patients with a proven causal mutation. This testing allows for the confirmation of diagnoses, early disease detection, alteration of disease progression, identification of the disease in relatives, and application of targeted therapy. Such practices carry numerous ethical dilemmas, including the psychological impact on patients, family implications, and protecting patients' rights and privacy. The implementation of genetic testing in everyday clinical practice will gradually become standard. With the development of diagnostic algorithms, it will enable earlier diagnosis, risk assessment, and the informing of patients and their relatives about their health condition.