The joint European ESC/EACTS Society1 in 2012 and the American AHA/ACC Association2 in 2014 guidelines for the treatment of valvular disease clearly state that percutaneous balloon valvuloplasty should be considered first for simple mitral stenosis (Class Ia evidence-based medical grade). Clinical studies have shown that the success rate of pbmv surgery is over 95%, and the majority of patients have significantly enlarged valve opening area and improved heart function by 1-2 grades after surgery. pbmv avoids open-heart surgery, causes little damage to patients, and results in rapid postoperative recovery. It has basically replaced the traditional surgical mitral valve stenosis separation surgery. 1, percutaneous mitral balloon valvuloplasty indications and contraindications: indications: ① moderate or severe simple mitral stenosis, no significant valve deformation, good elasticity, no serious calcification, no significant abnormalities in subvalvular structures, no thrombus in the left atrium, no significant closure incompetence or a small amount of mitral valve closure incompetence, orifice area ≤37.5px2, preferably sinus rhythm. ② Restenosis after mitral junctional separation surgery, atrial fibrillation, mitral valve calcification, combined with mild mitral or aortic valve closure insufficiency, can be used as relative indications. ③ mitral stenosis with severe pulmonary hypertension, too small left ventricle, those with high risk of surgical treatment and those who are not suitable for valve replacement can also be selected for pbmv. Contraindications: rheumatic activity, history of embolism in the body circulation and severe arrhythmias, significant deformation of the mitral leaflets, severe abnormalities of the subvalvular structures, moderate or greater closure insufficiency of the mitral or aortic valve, and contraindication to atrial septal puncture. 2.Preparation for percutaneous mitral balloon valvuloplasty: ① Understand the condition in detail and assist the physician to do various tests such as electrocardiogram, echocardiogram, cardiac function, blood type, and clotting time. ② Material preparation: prepare various catheters, sterile instruments, saline, contrast agents, heparin and emergency drugs commonly used in cardiovascular disease such as lidocaine, atropine, isoproterenol, dexamethasone, etc. needed for the operation. ③ Pre-operative detailed inquiry about any allergy history was done. And do skin preparation of the corresponding surgical site, the skin preparation range is both sides of the groin and perineum skin, in case one side of the puncture fails, change to the opposite side. The patient was instructed to abstain from food, water and urine early in the morning of the day of surgery. Valium 10mg was given intramuscularly 30min before surgery as prescribed by the doctor. 3.Surgical procedure of percutaneous mitral balloon valvuloplasty: Surgical procedure: illustrated by the paraclinal route technique. Using the seldinger technique, the right femoral vein was punctured and cannulated, a right heart catheterization was performed to observe the oxygen saturation, pulmonary artery pressure, pulmonary capillary inotropic pressure and to measure cardiac output in each department, and a brockenbrough puncture needle was fed through the right femoral vein to puncture the interatrial septum and feed two and a half turns of guidewire (Figure 1). After successful puncture of the interatrial septum and delivery of 2 semicircular guidewires, the femoral venous puncture hole and interatrial septal puncture hole are dilated with a 14f dilator, followed by delivery of a balloon catheter (Inoue Balloon Catheter System) through the guidewire and dilatation of the mitral valve orifice with balloon inflation under continuous screen monitoring (Figures 2-5). Figure 2. PBMV step – balloon fed along 2 ½ turns of the guidewire Figure 3. PBMV step – balloon enters the left ventricle and fills the left balloon Figure 4. Repeat right and left heart catheterization and echocardiography to observe the effect of dilatation. 4.Postoperative efficacy of percutaneous mitral balloon valvuloplasty: The indicators for judging the clinical success of pbmv are: ① The apical diastolic murmur disappears or is significantly attenuated. Cardiac function improves by more than one grade. ②The mean left atrial pressure ≤ 1.5kpa (11mmhg) and mitral valve pressure difference ≤ 18mmhg (2.4kpa). ③Increased cardiac output and decreased whole lung resistance, ④Mitral orifice area was ≥2cm2, ⑤No important complications occurred.