The relationship between the heart and the lung is signified by the inter-dependence between qi and blood. Physiologically, the lung dominates qi and assists the heart to propel blood circulation; the heart governs blood and blood nourishes the lung and maintains the respiratory function of the lung. Since the pectoral qi accumulates in the chest, by means of flowing in the heart vessels to propel qi and blood and running in the respiratory tract to regulate respiration, to warm the heart and the lung, it can strengthen the coordination between the heart and the lung in propelling blood circulation and governing respiration.

 

Pathologically, deficiency of lung-qi and disorder of the lung in dispersing and descending will affect the function of the heart to propel blood; insufficiency of heart-yang will weaken blood circulation, leading to disorder of lung in respiration with the symptoms of cough, asthma, chest oppression and palpitation.