Left heart failure is due to the contractile function of the heart muscle or special reasons, resulting in a sudden impairment of the heart’s blood-exhausting function, called acute left heart failure. The specific symptoms are as follows: 1. The clinical manifestations of acute left heart failure are particularly severe chest tightness, shortness of breath, and even recurrent coughing and coughing of pink frothy sputum. This condition is called paroxysmal dyspnea, with not enough air, or not being able to sleep flat at night and having to sit down, coughing, hemoptysis, and coughing pink foamy sputum when lying down; 2. Acute left heart failure will be accompanied by increased heart rate, as well as increased respiratory rate, and even profuse sweating and cyanosis of the lips. Most of this acute left heart failure is based on chronic heart failure, due to infection, rapid arrhythmia, sudden emotional excitement, anger, or depression leading to acute left heart failure episodes; 3. Some acute left heart failure is the most acute left heart failure when the original health, such as once being an athlete, suddenly develops chest tightness and inability to lie down during running, which leads to acute tendon rupture. There are also some acute heart attacks that suddenly present with shortness of breath, dyspnea, and profuse sweating, and acute heart attack combined with acute left heart failure. These are all critical clinical manifestations, a state that requires urgent first hospital consultation, and one of the most critical complications of heart disease.