Advances in molecular genetics during the past decades led to seminal discoveries in the genetic basis of cardiovascular diseases, resulting in a new understanding of their pathogenesis, determinants of natural history and more recently paved the way for innovative therapies. A significant gap, however, exists between the rapidly increasing knowledge, especially of cardiovascular Mendelian disorders, and the medical applications in daily practice. This paper will focus on the practical issues the cardiologist may be faced with when suspecting a Mendelian disorder. The objective is to review the general issues related to genetic counselling and genetic testing, and to provide key messages for their integration into the medical management of the patients and relatives, according to a precision medicine approach.