Figure 1: In the normal ventricular function curve: cardiac index (CI) and diastolic ventricular pressure (DP) are in normal limits. In heart failure, the curve deviates downward; and with normal DP (10 mmHg) the IC is 1.7 L / m2 / that is not enough to maintain in normal limits the blood pressure and tissue perfusion (tissue hypoperfusion).By other hand, the increase of diastolic volume, increases the CI, blood pressure and tissue perfusion it restores to normal cardiac function, but appears cardiomegaly and pulmonary congestion (dyspnea).