心脏应天少阴君火。为神明之主。生之本。神之居。十二经皆拱向听命。而咸输其气以应之。贡其精以养之。故心
为血之主。脉之宗。盖神以气存。气以精宅也。其精常满。故能分神于四脏。其气常充。故能引精于六腑。而肾家一脏。
又实为心居之尾闾。经云。心舍脉其主肾也。肾为心主。则必肾水足而后心火融。故养心之法有二。寡思虑。守恬愉。
使心无过量之用。无留根之事。此养之以气也。常握固戒多欲。使肾无淫佚之失。无相火之乘。此养之以精也。若用神
无方。则伤其气。伤其气并伤其精。而神遂归于空飞。守肾无节。则伤其精。伤其精遂伤其气。而水不能制火。阴不为
阳宅。而水气遂至凌心。是心病之始始于此也。是以心气未尝不有余。稍失血则为不足。心之不足有余。皆系乎血之盛
衰。血盛则耳目聪明。而神能寂照。血衰则虑易志耗。而昏妄交集。故凡火有余之症。皆为血不足。而血不足之候。又
皆能使火不足。其有余不足。皆不得与运气司天之火。淫火郁从乎火者同候。治要在养阴凝神。守精驭气。以匡政其有
余不足而已矣。经曰。心病者。胸中痛。胁支满。胁下痛。肩背胛闷痛。两臂内痛。虚则胸腹大。胁下与腰相引而痛。
盖心为血脉之主。其神明不受病。故或实或虚。皆不见本脏。而唯在血脉。其在血脉。必先以在经络者病之。如胸中痛
以及腹腰胁之间。皆手少阴手厥阴脉之所及。故先病于本经也。若当其虚则胸腹大。胁下与腰相引而痛。又缘脾胃之不
上输气。肾之不上贡精。故病亦相连耳。又非止经脉之故也。若心经络病者。为是动则嗌干心痛。渴而欲饮。以及所生
病。目黄胁痛。 臂内后廉痛厥。掌中热痛。此皆正经络病也。而其病又能及心。要其本末然也。嗌干者。其支脉挟咽
也。心火炎故心痛。火炎则阴耗。而心液干。且心部在阳明。心痛而热及阳明。故渴而欲饮也。目黄以下至掌中热痛。
皆心脉热逆也。又精气并于心。则喜惊而夺精。汗出于心。与忧思伤心者。心喜胜而恶负。并于心。则心有余故喜。乃
心之浮阳也。若惊者肝胆失不利。能为心捍。而心气内涸。故夺精。神不守营。故汗出。心之官则思。思而不胜则忧。
甚而不已则神明内空。空而不已。则神明内乱。故忧思皆足以伤心也。
心脏对应天时的少阴君火。它是神明的主宰，是生命的根本，也是神居住的处所。十二经脉都拱卫朝向它并听从它的命令，同时输送它们的气以响应心脏，贡献它们的精微物质以滋养心脏。所以心是血的主宰，脉的宗主。大概神依附于气而存在，气依附于精而安居。心的精微物质常常充盈，所以能将神分派给其他四脏；心的气常常充盛，所以能引导精微进入六腑。而肾脏这一脏，又确实是心脏居所的尾闾（关键关口）。医经说：“心舍脉，其主肾也。”肾为心的主宰，那么必须肾水充足而后心火才能温融。所以养心的方法有两种：一是减少思虑，保持恬淡愉悦，使心脏没有过度的消耗，没有遗留病根的事端，这是通过保养气来养心；二是经常握固（一种养生手势），戒除过多的欲望，使肾脏没有淫佚的过失，没有相火的乘袭，这是通过保养精来养心。如果用神没有节制，就会损伤气，损伤了气进而损伤精，于是神就归于空虚飘散；如果守肾没有节制，就会损伤精，损伤了精进而损伤气，于是水不能制约火，阴不能成为阳的宅舍，于是水气就会上凌犯心脏，这就是心脏病的起始原因。因此，心气未曾有过真正的有余，稍微失血就会导致不足。心的不足或有余，都取决于血的盛衰。血盛则耳目聪明，而神能寂静观照；血衰则思虑容易分散、意志耗损，而昏乱妄念交错出现。所以凡是火有余的症状，都是因为血不足；而血不足的证候，又都能导致火不足。这些有余和不足的情况，都不能与运气学说中司天之火、淫火郁而从化于火的证候混为一谈。治疗的要点在于滋养阴液、凝聚精神，守住精微、驾驭气机，以此来纠正其有余或不足的状态罢了。医经说：“心病者，胸中痛，胁部支撑胀满，胁下痛，肩背部及肩胛间闷痛，两臂内侧痛。虚证则见胸腹部胀大，胁下与腰部相互牵引而痛。”大概心是血脉的主宰，其神明本体不受病邪直接侵犯，所以无论是实证还是虚证，都不表现为本脏的直接病变，而只表现在血脉上。在血脉上的病变，必定先由经络中的疾病引起。如胸中痛以及腹、腰、胁之间的疼痛，都是手少阴心经和手厥阴心包经所循行的部位，所以先在本经发病。如果遇到虚证，则出现胸腹部胀大，胁下与腰部相互牵引而痛，这又是因为脾胃不能向上输布气，肾脏不能向上贡献精微，所以病症相互牵连。这也不仅仅是经脉的缘故。如果是心经络发生病变，属于“是动病”则见咽喉干燥、心痛、口渴想饮水，以及它所生的病，如目黄、胁痛、手臂内侧后缘疼痛甚至厥冷、手掌中心发热疼痛。这些都是正经经络的病变。而这些病症又能波及心脏，究其根本末节，道理如此。咽喉干燥，是因为心经的支脉挟持咽喉；心火炎上故心痛；火炎则阴液耗伤，而心液干枯；而且心所属的部位在阳明经区域，心痛且热邪波及阳明经，所以口渴想饮水。从目黄以下至手掌中心发热疼痛，都是心脉热邪逆乱所致。另外，精气合并于心，则会喜欢受惊而耗夺精微；汗出于心，这与忧思伤心有关。心喜欢胜而厌恶失败，精气并于心，则心有余所以喜欢（此处指心神外越之喜），这是心的浮阳表现。若受惊，则是肝胆功能不利，不能为心脏捍卫，导致心气内里枯竭，所以耗夺精微；神不能守持营气，所以出汗。心的官能主司思考，思考而不能胜任则产生忧愁，严重且不停止则神明在内空虚，空虚且不停止则神明在内混乱。所以忧思都足以伤害心脏。
The Heart corresponds to the Shaoyin Ministerial Fire of Heaven. It is the master of Shen (Spirit), the root of life, and the dwelling place of the Spirit. The twelve meridians all surround it, submit to its command, transmit their Qi to respond to it, and contribute their Essence to nourish it. Therefore, the Heart is the master of Blood and the patriarch of vessels. Generally, Shen resides in Qi, and Qi dwells in Essence. Its Essence is constantly full, thus enabling it to distribute Shen to the other four Zang organs; its Qi is constantly abundant, thus enabling it to guide Essence into the six Fu organs. Among them, the Kidney, as a single organ, serves as the tailgate (critical outlet) of the Heart's residence. The Classics state: "The Heart houses the vessels, and its master is the Kidney." Since the Kidney is the master of the Heart, only when Kidney Water is sufficient can Heart Fire be harmoniously melted. Thus, there are two methods for nourishing the Heart: first, reduce mental exertion and maintain tranquility and joy, ensuring the Heart has no excessive usage and no lingering roots of disease; this is nourishing via Qi. Second, frequently practice holding the fist (a health-preserving gesture) and guard against excessive desires, ensuring the Kidney has no licentious excesses and no invasion by Ministerial Fire; this is nourishing via Essence. If the use of Shen lacks method, it injures Qi; injuring Qi further injures Essence, and Shen eventually returns to emptiness and flight. If guarding the Kidney lacks restraint, it injures Essence; injuring Essence further injures Qi, and Water fails to control Fire, Yin fails to serve as the residence for Yang, and Water Qi ascends to overwhelm the Heart. This is the beginning of Heart disease. Hence, Heart Qi is never truly in excess; slight blood loss leads to deficiency. Both the deficiency and excess of the Heart depend on the prosperity or decline of Blood. When Blood is prosperous, the eyes and ears are acute, and Shen can observe quietly; when Blood declines, thoughts become scattered and willpower dissipates, leading to confusion and delusion. Therefore, all symptoms of Fire excess are due to Blood deficiency, and signs of Blood deficiency can also lead to Fire deficiency. These conditions of excess and deficiency must not be conflated with the patterns of Si Tian Zhi Fire (Heavenly Ruling Fire in Five Movements and Six Qi) or Yin Huo (Deficient Fire arising from stagnation). The key to treatment lies in nourishing Yin, consolidating Shen, preserving Essence, and controlling Qi, thereby correcting any excess or deficiency. The Classics state: "In Heart disease, there is pain in the chest, distension and fullness in the hypochondrium, pain below the hypochondrium, stuffy pain in the shoulder, back, and scapula, and pain in the inner aspect of both arms. In deficiency, there is abdominal and thoracic distension, and pulling pain between the hypochondrium and the waist." Generally, the Heart is the master of the blood vessels, and its Shen (spiritual aspect) does not directly suffer from pathogens. Therefore, whether excess or deficiency, the primary manifestation is not in the Zang organ itself but in the blood vessels. Lesions in the vessels must first arise from diseases in the meridians. For instance, pain in the chest extending to the abdomen, waist, and hypochondrium involves the pathways of the Hand-Shaoyin (Heart) and Hand-Jueyin (Pericardium) meridians; thus, the disease originates in these primary meridians. In cases of deficiency, such as abdominal/thoracic distension and pulling pain between the hypochondrium and waist, this is also due to the Spleen and Stomach failing to transport Qi upward and the Kidneys failing to contribute Essence upward, causing interconnected pathology. This is not solely due to meridians. If the Heart meridian collaterals are diseased, "Shi Dong" (Moving) diseases include dry throat, heart pain, thirst with desire to drink, and generated diseases such as yellow eyes, hypochondriac pain, pain and coldness along the posterior medial aspect of the arm, and heat/pain in the palm. These are proper collateral diseases. However, these pathologies can also affect the Heart itself, following the principle of root and branch. Dry throat occurs because the collateral branches accompany the throat; Heart Fire flaring causes heart pain; Fire flaring consumes Yin, drying Heart fluids; furthermore, the Heart's domain relates to the Yangming area, so heart pain with heat affecting Yangming causes thirst. From yellow eyes to palm heat/pain, all result from rebellious Heat in the Heart vessels. Additionally, when Essence and Qi merge in the Heart, one may feel prone to fright and lose Essence; sweat emerges from the Heart. This relates to worry and thought damaging the Heart. The Heart prefers victory and dislikes defeat. When Qi/Essence merges excessively, the Heart appears有余 (excess), manifesting as inappropriate joy, which is Floating Yang of the Heart. Fright arises when the Liver and Gallbladder fail to function smoothly and cannot defend the Heart, causing internal depletion of Heart Qi and loss of Essence; since Shen does not guard Ying (Nutritive) Qi, sweat ensues. The Heart's function governs thought. Unsuccessful thinking leads to worry; if worry persists without end, Shen becomes internally empty; if emptiness persists, Shen becomes internally chaotic. Thus, worry and thought are sufficient to damage the Heart.