Cardiac resynchronization therapy (CRT) is an effective treatment for a subgroup of heart failure patients, but more than 30 % of those selected do not respond. Inadequate criteria for patient selection and optimization are the main causes of the high non-response rate. Mechanical parameters, such as work done during the isovolumetric phase, are promising, but are complicated and require invasive measurements. In this study, we use a computational modeling framework to calculate the regional stress of the left ventricular wall of seven CRT patients and seven healthy controls. The standard deviation of the regional wall stress at the time of mitral valve closure (SD_MVC) was used to quantify dyssynchrony and was compared between patients and controls and among the patients. The results show that SD_MVC is significantly lower in controls compared to patients and correlated with the degree of long-term response among the patients based on end-diastolic volume reduction. The patients with lower SD_MVC responded best to therapy. The patient with the highest SD_MVC was the only non-responder in the cohort. The distribution of fiber stress at the beginning of the isovolumetric phase seems to correlate with the degree of response and this parameter could potentially improve patient selection and optimization of CRT. Further studies with a larger cohort are needed to validate these results.