A early diagnosis device (100) of cardiopathies in a patient (50) such as a cardiac decompensation and/or cardiovascular diseases comprises a wearable support (1) and a diagnostic unit (5) mounted to the wearable support (1). The diagnostic unit (5) comprises a means for delivering (10) an electric current stimulus (Ii), at a predetermined frequency (fi) to the patients body (50) and a means for measuring (20) a thoracic electrical bioimpedance (Zi), which is adapted to provide a bioelectric impedance signal (Zi) on the basis of the electric stimulus (Ii) at the predetermined frequency (fi). The device (100) further comprises an adjustment means (30) for adjusting the frequency (fi) of the electric stimulus (Ii) in way suitable for transmitting a plurality of electric stimuli (I1, I2,... In) at respective different frequencies (f1, f2, f3... fn) and such that the means for measuring (20) detects a corresponding complex bioimpedance signal (Z1, Z2, Z3, Zn). In addition, the device comprises a memory (35) that is configured to store the complex bioimpedance signals at a first time (ti), at a second time (t2) and at an nth time (tn) and a means for extracting the real part (R1, R2, R3... Rn) of the complex signals for instants (t1, t2, tn), to obtain a respective time chart (C1, C2, Cn) of the real part for each frequency. Furthermore, it comprises a means for analysing (40) the time chart (C1, C2, Cn) and a means to provide an alarm (46) of cardiac decompensation if a decrease value DR/Dt is higher than a predetermined value DRo/Dt.Linvention porte sur un dispositif de diagnostic précoce (100) de cardiopathies chez un patient (50), telles quune décompensation cardiaque et/ou des maladies cardiovasculaires, lequel dispositif comprend un support (1) portable et une unité de diagnostic (5) montée sur le support (1) portable. Lunité de diagnostic (5) comprend un moyen pour ladministration (10) dun stimulus de courant électrique (Ii), à une fréquence prédéterminée (fi) au