Abstract: The invention relates to a process for the measurement of cardiac volumes of the beating heart, in pulsed flow conditions, by means of a tracer injected upstream of or in the ventricle at a controlled injection flow D.sub.i during a controlled injection time t.sub.i. The variation of concentration .DELTA. of the tracer with respect to time, in a pulsed flow regime varies in a steplike manner, the concentration at each cardiac cycle n being .DELTA.n.According to the invention, after acquiring the concentration .DELTA. of the tracer during a number N of complete cardiac periods and computing the step concentration .DELTA.n, the mean cardiac period .tau. from the number of recorded cardiac cycling intervals n, the following summated concentration products can be formed: ##EQU1## where m is any cycle corresponding to or occurring after the M.sup.th cardiac cycle but before the N.sup.th cycle (M.ltoreq.

Abstract: The invention relates to a process for measuring the cardiac capacity or cardiac stasis at each heart beat V by dilution of the indicator (stain or frigories) injected above the heart, as well as an apparatus for performing this process.According to the invention, a quantity Q.sub.i of indicator is injected at a constant flow rate D.sub.i for a time t.sub.i corresponding to at least two heart beats, wherein the concentration of indicator in the blood (or the temperature variation in the blood) is measured at the end of indicator injection .DELTA..sub.m and .DELTA.(t) being the indicator concentration (or temperature variation) as a function of the time t assuming t = O at the start of the injection, t.sub.m being the time at the end of the injection, the integrals ##EQU1## ARE MEASURED AND THEN THE CARDIAC CAPACITY (V) is deduced from the thus measured values.