Graphical analysis of high-volume heart failure

The figure provides an analysis of two types of high cardiac output cardiac failure. One type due to venous catheterization increases the burden on the heart by increasing the amount of venous blood poured in, even the heart's ability to pump blood does not decrease. Another type is due to beriberi when the return of venous blood increases due to a decrease in systemic vascular resistance, but at the same time, the heart's ability to pump blood decreases.

Figure. Graph of two types of conditions that can cause high output heart failure: (1) venous catheterization (AV) and (2) beriberi.

Varicose veins

The normal curve in the figure indicates normal cardiac output and the normal return curve of venous blood volume. These three curves are equal at point A, showing a normal cardiac output of 5 L / min and right atrial filling pressure of 0 mmHg. Systemic vascular resistance is reduced due to the large venous opening. The return curve of venous blood flow is called "atrioventricular catheterization". The venous return curve is equal to the cardiac output curve at point B, with a cardiac output of 12.5 L / min and right atrial pressure of 3 mmHg. As a result, cardiac output increases sharply, right atrial pressure slightly increases, and there are signs of peripheral obstruction. With exercise, there will be less cardiac reserve due to the ability of the heart to reach near-maximal levels to pump more blood through the venous vents.

Beriberi

The figure shows the change in the curve of cardiac output and venous blood return due to beriberi. Decreased cardiac output curve due to weak heart muscle due to thiamine deficiency due to beriberi. Weakened heart muscle reduces blood flow to the kidneys. As a result, the kidneys retain large amounts of fluid, increasing systemic filling pressure (represented by the point where the venous return curve intersects the zero cardiac output curve) from a normal value of 7 mmHg to 11. mmHg. This pushes the venous blood flow curve to the right. Finally, the venous blood return curve rotates upward from the normal line due to thiamine deficiency resulting in peripheral vasodilation. The two blue curves (cardiac output and venous return) intersect at point C, describe the circulatory state in beriberi with right atrial pressure in this example of 9 mmHg and a cardiac output 65% higher than normal; cardiac output is high despite weak heart muscle, as shown by a decrease in a peak output of the cardiac output curve.