Shortness of breath, tachycardia and dizziness may be caused by left heart failure, asthma and acute pulmonary heart disease. 1. Left heart failure: shortness of breath and tachycardia may occur due to obstruction of circulation in the left heart system, resulting in stagnation of the pulmonary circulation. Dizziness occurs when the volume of cardiac excretion decreases, leading to inadequate perfusion of tissues and organs. 2. Asthma: due to severe spasm of the airways will lead to shortness of breath, at the same time, the organization of hypoxia, on the one hand, hypoxia will cause reflex heart rate increase. In a state of hypoxia, the brain does not get enough oxygen supply, there will be dizziness. 3. Acute pulmonary heart disease: for example, blood clots, air embolism, etc., all kinds of emboli block the pulmonary artery system, resulting in shortness of breath, tachycardia. If the pulmonary embolism is not relieved timely and effectively, there will be lack of oxygen to the brain, causing dizziness. Shortness of breath, tachycardia, and dizziness may also be caused by other reasons, it is recommended to promptly go to the emergency department, follow the doctor’s instructions for further examination, with the help of the doctor to clarify the cause, and targeted treatment or therapy.