Palpitations in the context of Cold Damage (Shanghan) disease. How shall this be elucidated? Palpitation refers to a state of inner fright and unease. The patient feels the heart beating violently ("zhuzhu titi"), with a sense of panic and instability, unable to remain at ease; this is palpitation.

The causes of heart palpitation do not exceed two types: one is Qi deficiency, and the other is fluid retention. In Cold Damage disease, if after two or three days there is palpitation accompanied by irritability, it should be treated with Xiaojianzhong Tang (Minor Construct the Middle Decoction). In Shaoyin disease presenting with cold extremities (Sini), if the patient experiences palpitation, Sini San (Four Reversal Powder) with an addition of 5 fen of Guizhi (Cinnamon Twig) should be used. This represents palpitation caused by Qi deficiency. Drinking excessive amounts of water inevitably leads to palpitation in the epigastrium; this represents palpitation caused by fluid retention.

In cases of palpitation due to Qi deficiency, it arises because internal Yang Qi is weak, leaving the epigastrium empty, causing the righteous Qi to move internally and generate palpitation. In cases of palpitation due to fluid retention, it arises because water stagnates in the epigastrium. The Heart belongs to Fire and dislikes Water; since water has stagnated internally, the Heart cannot remain at peace, thus generating palpitation. Furthermore, after sweating or purging therapies, when internal righteous Qi becomes deficient and pathogenic factors attack mutually, resulting in palpitation, this condition is more severe than palpitation caused solely by Qi deficiency. In Taiyang disease, if sweating is excessive, the patient may cross their hands over the heart region, feeling palpitation in the epigastrium. If Taiyang disease is incorrectly treated with purgation, leading to heaviness of the body and palpitation in the epigastrium, sweating therapy must not be used. In Shaoyang disease, vomiting and purging are contraindicated; if mistakenly applied, they cause palpitation and fright. Sweating is also contraindicated in Shaoyang disease; if mistakenly applied, it leads to delirious speech, which pertains to the Stomach. If the Stomach harmonizes, recovery occurs; if the Stomach does not harmonize, irritability and palpitation ensue. These instances all represent post-sweating conditions complicated by residual pathogens, differing from palpitation caused by Qi deficiency. Treatment may involve stabilizing and consolidating methods or resolving and dispersing methods, but one must first determine the nature of the floating Qi.

Additionally, excessive drinking of water, where fluids fail to be distributed and disseminated properly, remains in the epigastrium; if severe, palpitation occurs. The *Jingui Yaolue* states: "When food intake is low but water intake is high, water stagnates in the epigastrium; if severe, palpitation occurs." Palpitation caused by fluid retention is more serious than that caused by other pathogens. Even if there are other residual pathogens, the palpitation must be treated first. Why? Because water stagnates in the epigastrium; if the water qi scatters, it will go everywhere. If it infiltrates the Lungs, it causes wheezing and coughing; if it transmits to the Stomach, it causes hiccups (Yue) and retching/vomiting; if it overflows into the skin, it causes edema; if it soaks into the intestines, it causes diarrhea. This situation cannot be delayed. The Classics state: "In cases of cold extremities accompanied by palpitation in the epigastrium, it is appropriate to first treat the water, administering Fuling Gancao Tang (Poria and Licorice Decoction), and subsequently treat the cold extremities. Otherwise, if water soaks the Stomach, diarrhea will certainly occur." Cold extremities indicate deep-seated pathogens, yet water treatment is prioritized; how much more so for superficial pathogens? Should physicians not investigate this deeply?