Bone marrow mononuclear stem cells transplanted in rat infarct myocardium improved the electrical conduction without evidence of proarrhythmic effects.
OBJECTIVE
The arrhythmogenic effect of stem cells transplantation (SCT) in an infarct myocardium is still unknown. We investigated arrhythmogenicity of SCT in rat cryo-infarct model.


METHODS
In rat cryo-infarct model, bone marrow mononuclear stem cells (MNSC, 1 x 10(7) cells) were transplanted into the infarct border zone (BZ) of the LV epicardium. We compared the optical mapping and inducibility of ventricular tachycardia/fibrillation (VT/VF) among normal (n=5), cryo-infarct (n=6), and SCT rats (n=6).


RESULTS
The VT/VF inducibility was higher in the cryo- infarct (47.2%, p=0.001) and SCT groups (34.6%, p=0.01) than in the normal group (12.8%). The induced VT/VF episodes persisted for more than 2 minutes in 4.3%, 26.4% and 17.3% in the normal, cryo-infarct and SCT group, respectively. In the SCT group, the action potential duration at 70% was shorter at the SCT site than the BZ during SR (75.2 +/- 8.1 vs. 145.6 +/- 4.4 ms, p=0.001) and VT (78.2 +/- 13.0 vs. 125.7 +/- 21.0 ms, p= 0.001). Conduction block was observed at the SCT site and BZ during VT. However, no reentry or ectopic foci were observed around the SCT sites.


CONCLUSIONS
The electrical conduction was improved by SCT without evidence of augmentation of arrhythmia in the rat cryo-infarct model.
Joung
Boyoung
B
Division of Cardiology, Yonsei University College of Medicine, 250 Seongsanno, Seodaemun-gu, Seoul 120-752, Korea.
Kim
Il-kwon
IK
Lee
Moon-Hyoung
MH
Yoo
Kyung-Jong
KJ
Kim
Sung-Soon
SS
D000200:Action Potentials; D000818:Animals; D001145:Arrhythmias, Cardiac / Q000209:etiology*; D016026:Bone Marrow Transplantation / Q000009:adverse effects*; D004195:Disease Models, Animal; D004553:Electric Conductivity; D006352:Heart Ventricles / Q000473:pathology / Q000637:transplantation; D018380:Hematopoietic Stem Cell Transplantation / Q000009:adverse effects*; D066298:In Vitro Techniques; D009203:Myocardial Infarction / Q000473:pathology / Q000601:surgery*; D051381:Rats; D017207:Rats, Sprague-Dawley