Background <p>Mechanical forces significantly influence the initiation, progression, and remodeling of cardiovascular disease. In this study, CT-based patient-specific computational models were constructed to investigate the effects of the successful septal myectomy on myocardial stress distribution in the left ventricle.</p> Methods <p>CT imaging data from five patients, collected both before and after successful septal myectomy, were used to create 10 patient-specific finite element models. Myocardial stress and strain of all integral nodes in the myocardium of the left ventricle were extracted from the simulation results. All the nodes in the left ventricular wall were divided into apex, midventricular, and basal region groups according to their position in the left ventricle.</p> Results <p>It was found that the mean stress decreased by 27.7% (<i>p</i> &lt; 0.001) and the mean strain decreased by 26.3% (<i>p</i> &lt; 0.001) after the surgery. The reduction in myocardial stress was more pronounced in the midventricular (50.3% decrease) and apex (54.0% decrease) regions compared to the basal region (23.5% decrease).</p> Conclusions <p>These findings suggest that successful septal myectomy significantly reduces myocardial stress within the left ventricle, particularly in the midventricular and apex regions. Beyond alleviating left ventricular outflow tract obstruction, this surgery may also lower the risk of myocardial ischemia, acute myocardial injury, and subsequent myocardial fibrosis by reducing myocardial stress.</p>