Retrospective comparative surgical results in 172 patients who underwent mitral valve surgery using either a vertical transseptal (n = 110) or conventional left atriotomy (n = 62) approach are presented. The incidence of postoperative junctional arrhythmia (in patients in sinus rhythm preoperatively), ischemia time and total postoperative bleeding was significantly higher in the vertical transseptal approach group. No surgery-related deaths occurred. Vertical transseptal extended atriotomy provides excellent exposure for mitral valve surgery; the disadvantages of longer ischemia time and increased surgical bleeding are offset by the superior and more complete surgical reconstruction achieved. However, advantages of the technique are undermined by a higher incidence of junctional arrhythmia which, even if temporary, requires strict postoperative monitoring.