Cardiopulmonary bypass (CPB) time was used as the main variables for evaluation and visualization of the total thoracoscopic mitral valve plasty (MVP) learning curve using Cumulative sum.Cumulative sum (CUSUM) is a statistical method that focuses on results rather than on the process of performing a program skills, it generates graphs that allow for quick detection of deviations from pre-established standards and is an alternative tool that can be used to evaluate the performance of individual program. CUSUM can be generated based on set acceptable and unacceptable failure rates and the degree to which type 1(α) and type 2(β) errors (false positive and false negative errors) will be tolerated. CUSUM was defined as Sn = ∑(Xi -p0), where Xi = 0 for success and Xi = 1 for failure, p0 is the target reference.

Aortic clamping (AC) time was used as the main variables for evaluation and visualization of the total thoracoscopic mitral valve plasty (MVP) learning curve using Cumulative sum.Cumulative sum (CUSUM) is a statistical method that focuses on results rather than on the process of performing a program skills, it generates graphs that allow for quick detection of deviations from pre-established standards and is an alternative tool that can be used to evaluate the performance of individual program. CUSUM can be generated based on set acceptable and unacceptable failure rates and the degree to which type 1(α) and type 2(β) errors (false positive and false negative errors) will be tolerated. CUSUM was defined as Sn = ∑(Xi -p0), where Xi = 0 for success and Xi = 1 for failure, p0 is the target reference.