Περίληψη:
Introduction: The effects of myocardial ischaemia preconditioning in
pigs on the vulnerability to ventricular fibrillation during subsequent
ischaemic events are controversial. This study examined the time course
of changes in ventricular fibrillation (VFT) and defibrillation (DFT)
thresholds during transient myocardial ischaemia after a 45 min
preconditioning period.
Methods and results: In five open-chest pigs, VFT was measured after 3
min of regional myocardial ischaemia, at time 0, 2, 15, 30, 60 and 90
min (Control group). In seven other pigs (Test group), VFT was measured
before (time 0) and 2, 15, 30, 60 and 90 min after ischaemic
preconditioning by three consecutive 5 min periods of regional coronary
occlusion, followed by 10 min of reperfusion. DFT was measured by
increasing the stored energy systematically until successful
defibrillation. Ischaemic preconditioning caused no significant change
in the effective refractory period (ERP), VFT or DFT over the 90 min of
the experiments. In the Control group, ERP remained stable for 30 min,
though was significantly lower at 90 min (178 +/- 28 ms) than at
baseline (204 +/- 32 ms, P = 0.007). VFT and DFF remained unchanged
throughout the experiments, and no difference was observed in ERP, VFT
and DFT between the two groups at any time during the experiment.
Conclusion: No changes were observed in the refractory duration,
ventricular vulnerability or defibrillation energy requirements up to 90
min after ventricular ischaemic preconditioning in the pig. (c) 2004
Elsevier Ireland Ltd. All rights reserved.
Συγγραφείς:
Anastasiou-Nana, MI
Tsagalou, EP
Mavrikakis, EM
Siafakas, KX
and Tsolakis, EJ
Drakos, SG
Dalianis, A
Karelas, J and
Terrovitis, JV
Nanas, JN
