A method, an implantable medical device, and a computer-readable medium encoded with programming instructions allow monitoring of a hematocrit value and an SvO2 level of a patient, making use of at least one medical lead connected to an implantable medical device that carries an optical sensor module that measures at least one hematocrit value and at least one SvO2 value using at least first, second and third light radiation wavelengths, by determining a present hematocrit value from at least one of the measured hematocrit values and determining a present SvO2 value from at least one of the measured SvO2 values, and determining a patient status by evaluating the present hematocrit value and the present SvO2 value, to allow a change in the patient status to be identified.