A system for evaluating haemodynamic function in a human or animal subject, the system comprising: one or more transducers for monitoring continuously over time, either directly or indirectly at least two haemodynamic variables of the subject selected from the group including Systemic Perfusion Pressure, Systemic Vascular Resistance and Cardiac Output, wherein the haemodynamic variables are related according to the relationship SPP = CO×SVR; and generating one or more corresponding first data signals; a processor configured for: receiving the one or more first data signals; receiving data signals representing Heart Rate and Stroke Volume measured from the subject, either directly or indirectly, over a corresponding time period, and adjusting the one or more first data signals for the number of left ventricular contractions of the heart occurring per minute, represented by HR, by determining actual Systemic Vascular Resistance (aSVR), where aSVR = SVR×HR and where CO = HRxSV; and wherein said relationship SPP = COxSVR is re-expressed as SPP = SV × aSVR; and generating a display signal for a visual representation of the adjusted one or more first data signals, wherein the visual representation plots SV in a first dimension and aSVR in a second dimension; and a display device receiving the display signal and generating the visual representation; wherein haemodynamic function is determinable upon inspection of the visual representation. one or more transducers for monitoring continuously over time, either directly or indirectly at least two haemodynamic variables of the subject selected from the group including Systemic Perfusion Pressure, Systemic Vascular Resistance and Cardiac Output, wherein the haemodynamic variables are related according to the relationship SPP = CO×SVR; and generating one or more corresponding first data signals; a processor configured for: receiving the one or more first data signals; receiving data signals representing Heart Rate and Stroke Volume measured from the subject, either directly or indirectly, over a corresponding time period, and adjusting the one or more first data signals for the number of left ventricular contractions of the heart occurring per minute, represented by HR, by determining actual Systemic Vascular Resistance (aSVR), where aSVR = SVR×HR and where CO = HRxSV; and wherein said relationship SPP = COxSVR is re-expressed as SPP = SV × aSVR; and generating a display signal for a visual representation of the adjusted one or more first data signals, wherein the visual representation plots SV in a first dimension and aSVR in a second dimension; and a display device receiving the display signal and generating the visual representation; wherein haemodynamic function is determinable upon inspection of the visual representation. receiving the one or more first data signals; receiving data signals representing Heart Rate and Stroke Volume measured from the subject, either directly or indirectly, over a corresponding time period, and adjusting the one or more first data signals for the number of left ventricular contractions of the heart occurring per minute, represented by HR, by determining actual Systemic Vascular Resistance (aSVR), where aSVR = SVR×HR and where CO = HRxSV; and wherein said relationship SPP = COxSVR is re-expressed as SPP = SV × aSVR; and generating a display signal for a visual representation of the adjusted one or more first data signals, wherein the visual representation plots SV in a first dimension and aSVR in a second dimension; and a display device receiving the display signal and generating the visual representation; wherein haemodynamic function is determinable upon inspection of the visual representation.