Abstract: A method of and system for determining ventricular ejection fraction of a patient is provided. A pressure sensing device captures pulmonary arterial pressure data for a patient over time. A processing device receives the pressure data, generates a first time-resolved pressure curve, displaces the pressure values of the first time-resolved curve at least one time point and subtracts the displaced pressure values from the received pressure data to form a second time-resolved pressure curve so that the second curve has two or more distinct pulses from which an initial pulse may be isolated and an area may be calculated. The processing device determines an average pressure by averaging the pressure data of the first curve over a cardiac cycle of data; determines a cardiac chamber stroke volume for the patient; and uses the determined cardiac chamber stroke volume and determined average pressure to determine an ejection fraction for the patient.