Heart failure is one of the most frequent reasons for hospitalization due to a cardiac event. In most instances, the main difficulty is how to accurately evaluate left ventricular filling pressure. It can be evaluated clinically, biologically and invasively. Although historically, invasive management has been the reference, it is being used less and less frequently and expertise in the technique is being lost. This paper discusses the strength and weaknesses of the different techniques for evaluating filling pressure in these patients, and the importance of this parameter for their optimal treatment.