Objective To introduce a method of preoperative three-dimensional measurement by echocardiography to guide the surgical resection of hypertrophic obstructive cardiomyopathy (HOCM) and its long-term follow-up effect. MethodsBefore operation, each patient underwent transthoracic echocardiography to measure the length, width and thickness of diastolic ventricular septum hypertrophy on the long axis, short axis and four chamber sections, in order to establish three-dimensional measurement data of myocardial hypertrophy, and quantitatively estimate the location, depth and range of myocardium to be removed between 2014 and 2022 in our hospital. According to the quantitative data during operation, the hypertrophic myocardium of ventricular septum was resected to dredge the left ventricular outflow tract. ResultsForty-three patients were recruited, including 22 males and 21 females, aged 18-78 (49.2±5.1) years. Eighteen patietns underwent mitral valve surgery at the same time. All patients were satisfied with the relief of left ventricular outflow tract obstruction. Postoperative transesophageal echocardiography showed that the left ventricular outflow tract pressure gradient decreased significantly (94.2±28.1 mm Hg vs. 6.7±4.7 mm Hg, P<0.05). There was no ventricular septal perforation or complete atrioventricular block during the operation, and no one needed a secondary aorta-clamp for re-operation to remove hypertrophic myocardium again. Postoperative echocardiography showed that the mitral valve closed well or only had mild regurgitation, and the mitral systolic anterior motion sign basically disappeared. After 1.0-8.5 years of follow-up, the average pressure difference of left ventricular outflow tract remained below 10 mm Hg, and the clinical symptoms disappeared or improved significantly. Conclusion The quantitative prediction of the resection range of hypertrophic myocardium by three-dimensional measurement of preoperative echocardiography can accurately guide the surgical range of HOCM, avoid multiple blocking of aorta during operation, relieve left ventricular outflow tract obstruction to the greatest extent, and obtain better long-term results.