Five times of cardiac reoperations for PVE are a complex operation with significant risk. Due to the difficulty of aortic cross-clamping, mitral valve replacement (MVR) is performed under beating heart (BH) or ventricular fibrillation (VF) conditions. On-pump BH or VF valvular operations may have some technical advantages and utilities [1]. However, some studies have shown that the BH alternative with the VF approach is inferior to the empty heart technique due to its reduction in oxygen delivery to the subendocardium and the consequent suboptimal myocardial protection [2, 3]. In this case, we determined that it was difficult to perform MVR via the right thoracotomy procedure under the BH and VF techniques. Because, we had no previous experience with the BH technique in complex reoperation cases and, there was a need to secure a surgical field of view close to cardiac arrest. Moreover, though the VF condition was not an inappropriate myocardial protection strategy [4], in this case, the prolonged operative time was anticipated. The longer the VF time, the more reduction in oxygen delivery to the subendocardium, and the more creatine-kinase MB (CK-MB) increases [5, 6]. Therefore, in the case of VF, we thought that weaning from CPB was difficult under the prolonged VF time, and we chose the systemic hyperkalemia strategy during CPB to protect the heart.

This study was approved by the Institutional Review Board at Kitaharima Medical Center (IRB-0443) with the waiver of informed consent.