A method for automatically classifying clinical descriptions of patients by a computer processor using natural language processing is provided. The clinical descriptions relate to the use of a ventricular assist device to treat the patient. The method comprises receiving at least one clinical description comprising text. The method also then comprises determining the position of a target word within the text. Further the method comprises determining the existence of at least one negation word within an active region, the active region comprising a predetermined number of words within the text occurring immediately before and immediately after the target word, including the target word. The method then comprises determining the existence of at least one body-part word within the active region. Lastly, the method comprises determining that the clinical description is to be disregarded if the active region contains either a negation word or a body-part word.