A method of monitoring pressure within a medical patient, includes measuring an actual pressure in a medical patient in a first time period measuring an indicator of the actual pressure in the first time period, wherein the indicator is derived from an electrical signal of the patients heart determining a correlative relationship between the actual pressure and the indicator, wherein both the actual pressure and the indicator are obtained in the first time period measuring the indicator in a second time period and determining the actual pressure in the second time period based on the correlative relationship obtained in the first time period and the indicator obtained in the second time period.
