The difference in blood pressure between the left hand and the right hand is very big, it should be the big difference in blood pressure measurement between the left upper arm and the right upper arm, you need to go to the hospital for further examination, such as aortography, MRI, etc. to find out the cause of the cause of the problem and then treat it in time. Usually the difference between the two sides of the blood pressure of 20mmHg, often for physiological reasons, if more than 20mmHg and after the activity of dizziness, chest tightness and other symptoms need to go to the hospital immediately to find out the cause, such as vascular ultrasound, magnetic resonance imaging, aortography, etc., to find out the cause of the problem, and actively cooperate with the doctor for treatment. A large difference in blood pressure between the two sides of the common aortic coarctation, atherosclerosis, aortitis, etc., caused by the narrowing of blood vessels leading to a large difference in blood pressure, if you identify the cause of the diagnosis, as soon as possible treatment, so as to avoid delaying the condition.