Bone Marrow Cell Transplantation into the Heart is Not a Crucial Factor of Ventricular Fibrillation in a Rat Doxorubicin‐Induced Cardiomyopathy Model

To verify the susceptibility of ventricle to arrhythmia after bone marrow mononuclear cell transplantation (BMMNCT), we measured ventricular fibrillation threshold (VFT) and monophasic action potential duration (MAYD 90 ). Lewis rats with doxorubicin‐induced cardiomyopathy were divided into 2 groups: transplantation group (D‐TX: BMMNC (1 × 10 6 ) given transplants into the apex at 4 weeks after doxorubicin administration) and nontransplantation group (D‐N). Age‐matched normal group (N‐N) was prepared. At 4 weeks after BMMNCT, the following electrophysiologic tests were performed. Experiment 1 (VFT): Two stainless wires were placed at the apex and a single train of 10 square wave stimuli was delivered across T wave. The lowest current developing ventricular fibrillation was determined as VFT. Experiment 2 (MAPD 90 ): The catheter was inserted into the left ventricle and pressed against the endocardium near the apex under regular cycle lengths. Experiment 1: VFT of D‐TX and D‐N were significantly lower than that of N‐N (p < 0.01). There was no difference between D‐TX and D‐N. Experiment 2: MAYD 90 of each group was lined up in length D‐N>D‐TX>N‐N at every cycle lengths. There was a significant difference between D‐N and N‐N (p < 0.01), and D‐TX and N‐N (p < 0.05). In this model, BMMNCT did not increase susceptibility to arrthythmia.