Myocardial ischemia can lead to dyspnea. Patients with inadequate blood supply to the heart will suffer from lack of oxygen due to cardiac ischemia, and the lack of oxygen will cause the oxygen saturation of the arteries to drop and the partial pressure of oxygen to be too low, which will lead to varying degrees of dyspnea. Severe myocardial ischemia can lead to chronic cardiac insufficiency and heart failure. Patients with significant heart failure will have significant respiratory distress, even unable to lie down and can only sit and breathe. In patients with myocardial ischemia, the blood supply and oxygen supply to the heart should be corrected to be able to properly correct the dyspnea, but not all symptoms of dyspnea, due to myocardial ischemia, such as respiratory diseases, such as conditions like slow-onset lung, can also lead to dyspnea.