Method and device for determining the segmental volume and electrical parallel conductance of a cardiac chamber or blood vessel

An apparatus for determining a segmental volume of a cardiac chamber or a blood vessel of a patient, the apparatus comprising:

• a processing unit having a control output for initiating injection of a conductance indicator into a bloodstream of the patient, which influences electrical conductance of blood;
• a first detector configured to be placed in the cardiac chamber or blood vessel for measuring a conductance signal, which depends on the electrical conductance at the location of the first detector, wherein said processing unit is arranged for calculating the segmental volume of the cardiac chamber or the blood vessel from said conductance signal;
• a second detector configured to be placed in the bloodstream for measuring an indicator signal depending on a concentration of a concentration indicator in the blood, wherein said processing unit is arranged for calculating the cardiac output from an injected quantity of the conductance indicator and the indicator signal, and calculating the segmental volume and electrical parallel conductance of the cardiac chamber or blood vessel from the calculated cardiac output, the injected quantity of conductance indicator and the conductance signal.