Autologous in vitro expanded mesenchymal stem cell therapy for human old myocardial infarction.

BACKGROUND: Stem cell transplantation after myocardial infarction has been claimed to restore cardiac function. Mesenchymal stem cells attract a lot of attention because of the feasibility of in vivo and ex vivo differentiation to cardiomyocytes and endothelial cells as well as their trophic effect on tissue repair. In this study, we investigated the efficacy of autologous bone marrow derived mesenchymal stem cells in improving heart function in patients with old myocardial infarction. METHODS: Eight patients with old myocardial infarction and proper inclusion criteria were injected with mesenchymal stem cells at the time of coronary artery bypass grafting or percutaneous coronary intervention (test group) and compared with eight matched patients who received the same treatment without mesenchymal stem cell injection (control group). Evaluation of heart function was done by echocardiography plus single-photon emission computed tomography before and six months after the procedure. Serial clinical examination was performed every month through New York Heart Association class. RESULTS: The mean New York Heart Association class and single-photon emission computed tomography scan results decreased significantly in the test group (P=0.000 and 0.002, respectively) and in the control group (P=0.049 and 0.007, respectively) after the procedure at six months follow-up. Left ventricular ejection fraction increased significantly in the test group (P= 0.005) but not in the control group. In comparison between the test and control groups the results of New York Heart Association class assessment and single-photon emission computed tomography demonstrated significant improvement in the test group (P=0.005 and 0.013, respectively). There were no significant differences between the baseline variables in the two groups. CONCLUSION: Transplantation of ex vivo expanded bone marrow derived mesenchymal stem cell in patients with old myocardial infarction is a safe and feasible procedure. These cells improve the cardiac function without serious adverse effects.

Role of biatrial pacing in prevention of atrial fibrillation after coronary artery bypass surgery.

BACKGROUND: Atrial fibrillation (AF) after coronary artery bypass graft surgery (CABG) constitutes the most common sustained arrhythmia and results in prolonged hospitalization. The purpose of this study was to assess simultaneous right and left atrial pacing as prophylaxis for postoperative atrial fibrillation. METHODS AND RESULTS: From July 2003 to May 2004, 120 patients without structural heart disease and who underwent CABG were randomly classified into one of the following 3 groups: biatrial pacing (BAP), left atrial pacing (LAP), and no pacing (control). Atrial pacing was performed for 4 days. Post-CABG AF was significantly reduced in BAP group compared to single-site and control group (BAP, 17.5%; LAP, 30%; control, 45%; p=0.02). The mean length of hospital stay was significantly reduced in BAP group. Hospital charges were not significantly different between three groups. The mean length of hospital stay was most significantly reduced in BAP group (6.1+/-1.2 versus 9.0+/-4.1 days in the control groups; p=0.002, and 8.7+/-1.3 days in LAP groups; p=0.01). The mean length of stay in the intensive care unit was also significantly reduced in the BAP group (2.8+/-0.7 versus 4.6+/-4.5 days in control group; p=0.04, and 4.2+/-3.2 days in LAP group; p=0.01). CONCLUSIONS: Simultaneous right and left atrial pacing is well tolerated and is more effective in preventing post-CABG AF than single-site pacing, and, results in a shortened hospital stay. Identifying patients at risk for developing postoperative AF and using this prophylactic method may be the optimal effective strategy.