Heart failure is the abbreviation of heart failure, which is also called “congestive heart failure” or “cardiac insufficiency”. Due to the primary and secondary factors, the contraction of the heart muscle is weakened, and the blood cannot be fully discharged from the heart veins, so that the venous system is stagnant, and the blood supply of the arterial system is insufficient to meet the metabolic needs of the whole body and maintain effective circulation, so that a series of symptoms and signs appear, which is called heart failure. 1. Pay attention to the clinical manifestations of early heart failure: once symptoms such as exertional dyspnea or nocturnal paroxysmal dyspnea, increased heart rate, weakness, dizziness, insomnia, irritability and decreased urine output appear, contact your physician promptly and strengthen your observation. If manifestations such as extreme irritability, profuse sweating, and cyanosis of the lips occur rapidly, along with chest tightness, coughing, and dyspnea. Cyanosis, coughing a lot of white or pink foamy sputum, should be alert to the occurrence of acute pulmonary edema, immediately prepare to cooperate with rescue. 2. Regular observation of water-electrolyte changes and acid-base balance: hypokalemia may cause weakness, abdominal distension, palpitations, increased U waves and arrhythmia on ECG, and may induce digitalis toxicity. In a few cases, hyperkalemia can be caused by excessive potassium supplementation due to decreased renal function, which can lead to cardiac arrest in severe cases. Hyponatremia is manifested by weakness, loss of appetite, nausea, vomiting and drowsiness. Therefore, regular outpatient follow-up should be performed to check blood electrolytes and renal function.