A device for evaluating the ventricular-arterial coupling of a patient in real time, characterized in that it comprises computer means parameterized for: (i) receiving and treating, in real time, signals originating, on the one hand, from means for measuring arterial blood flow and, on the other hand, from means for measuring arterial pressure; (ii) displaying, in real time, the plot of at least one arterial pressure/flow loop; (iii) determining, on the final pressure/flow loop completed, the coordinates of the following points: A: point of the loop where the flow is zero and the pressure is at the minimum, B: point of the loop where the flow is highest, C: point of the loop where the pressure is highest, D: point of the loop where the flow is zero and the pressure is at the maximum; (iv) calculating the percentage of the area of the loop (Stot) occupied by the part S2 located between the straight lines and and/or the angle γ between these two straight lines and/or the acute angle δ between the straight lines and; (v) interpreting the results in the following way: if S2/Stot ≤ R2b and/or γ ≤ Gb and/or δ ≤ Db, the patient shows good ventricular-arterial coupling; if S2/Stot ≥ R2m and/or γ ≥ Gm and/or δ ≥ Dm, the patient shows poor ventricular-arterial coupling; in an intermediate situation, the quality of the ventricular-arterial coupling of the patient is intermediate, R2b, R2m, Gb, Gm, Db and Dm being predetermined thresholds. (i) receiving and treating, in real time, signals originating, on the one hand, from means for measuring arterial blood flow and, on the other hand, from means for measuring arterial pressure; (ii) displaying, in real time, the plot of at least one arterial pressure/flow loop; (iii) determining, on the final pressure/flow loop completed, the coordinates of the following points: A: point of the loop where the flow is zero and the pressure is at the minimum, B: point of the loop where the flow is highest, C: point of the loop where the pressure is highest, D: point of the loop where the flow is zero and the pressure is at the maximum; A: point of the loop where the flow is zero and the pressure is at the minimum, B: point of the loop where the flow is highest, C: point of the loop where the pressure is highest, D: point of the loop where the flow is zero and the pressure is at the maximum; (iv) calculating the percentage of the area of the loop (Stot) occupied by the part S2 located between the straight lines and and/or the angle γ between these two straight lines and/or the acute angle δ between the straight lines and; (v) interpreting the results in the following way: if S2/Stot ≤ R2b and/or γ ≤ Gb and/or δ ≤ Db, the patient shows good ventricular-arterial coupling; if S2/Stot ≥ R2m and/or γ ≥ Gm and/or δ ≥ Dm, the patient shows poor ventricular-arterial coupling; in an intermediate situation, the quality of the ventricular-arterial coupling of the patient is intermediate, R2b, R2m, Gb, Gm, Db and Dm being predetermined thresholds. if S2/Stot ≤ R2b and/or γ ≤ Gb and/or δ ≤ Db, the patient shows good ventricular-arterial coupling; if S2/Stot ≥ R2m and/or γ ≥ Gm and/or δ ≥ Dm, the patient shows poor ventricular-arterial coupling; in an intermediate situation, the quality of the ventricular-arterial coupling of the patient is intermediate,