This herbal formula is for a pattern that Traditional Chinese Herbal Theory calls "evil water shooting into the lungs".
Heart Yang Vacuity (CHF) Formula duty is to transform fluid accumulations: therefore it helps to normalize upper cavity fluid build-up. Traditional Chinese Herbal Theory calls this particular pattern:
"Yang Failing to Transform Fluids" and "Water Shooting into the Lungs"
The Spleen and Kidney Yang are the sources for fluid transformation. Thus if Spleen yang is deficient, fluids collect and transform into middle burner Dampness. If Kidney Yang endures damage, then water in the lower burner fails to transform and this creates an internal environment of Cold and severe Damp. This is a a condition of Yang deficiency. Yang fails to then transform Yin (fluids)....
These excess fluids is are called Water Evils, they flood upwards to harass the Heart, pour into the Lungs, and obstruct the Lung Qi mechanism. This turbidity also damages and weakens Heart Yang Qi which impedes the free flow of the movement of Blood (yin).
When blood is not flowing, the sovereign fire of the Heart fails to warm the ministerial fire of the Kidneys.
Damp Earth is damming the center, thus the Heart and Kidney fails to communicate. This is a systemic failure of the body's heating and cooling mechanisms.
This formula helps to transform middle jiao damp so that once again the heart yang properly performs it's warming function.
This is the method in which Traditional Chinese herbal theory reestablishes heart harmony.