The paper in early history of pulmonary medicine deals with studies of hypocapnia as a result of hyperventilation. Hyperventilation hypocapnia provokes respiratory alkalosis, subsequent ion changes in blood may cause disorders of myocardium conductivity and excitability resulted in arrhythmiae and even heart failure. Besides, hypocapnia limits the cerebral circulation which may be manifested in euphoria and even loss of consciousness. It is dangerous component of high altitude disease. Earliest medical descriptions of hyperventilation hypocapnia and its cardiac consequences are traditionally related with publications by an American physician of XIX age J.M. Da Costa and British doctor A.B.R. Myers. There exists a generally accepted eponym of "Da Costa syndrome". Hereby the authors for the first time coin data that disorders related to hyperventilation were described more than 360 years prior to Da Costa - by an Italian polymath of Renaissance epoch Leonardo da Vinci and suggest new eponym of "Leonardo da Vinci's syndrome". The article also briefly analyzes the medical studies of Leonardo da Vinci and his early contribution into Human Anatomy and Thyroidology.