Περίληψη:
Experimental studies have described an increase in ventricular
fibrillation threshold (VFT) by intravenous amiodarone. The aim of this
study was to examine the early time course of changes in VFT and
defibrillation thresholds (DFT) after an intravenous bolus of amiodarone
in an experimental pig model of transient myocardial ischemia. Methods
and results: VFT and relative effective ventricular refractory period
(ERP) were measured in 15 anaesthetized open-chest pigs after 3 min of
regional coronary ischaemia before (time 0) and 2, 15, 30, 60, and 90
min after the intravenous injection of normal saline (group A, n = 5) or
amiodarone, 5 mg/kg over 15 s (group B, n = 10). DFT was measured by
increasing the strength of DC shocks until defibrillation was
accomplished. Amiodarone caused an increase in VFT, starting at 2 min
after the infusion (11.4 +/- 8.4 mA versus 9.2 +/- 4.6 mA, P = 0.113),
became significant at 15 min (13.7 +/- 6.5 mA, P = 0.009) continued to
rise at 30 min (34.2 +/- 28.7 mA, P = 0.03) and reached a plateau at 60
min (50.3 +/- 37.8 mA, P = 0.008). An increase was also observed in the
ERP (204 +/- 25 ms at 2 min versus 197 +/- 26 ms at baseline, P = 0.074,
211 +/- 38 ms at 15 min, P = 0.084, 212 +/- 40 ms at 30 min, P = 0.037,
220 +/- 34 ms at 60 min, P = 0.002, and 227 32 ms at 90 min, P = 0.008).
No change was observed in DFT after amiodarone administration. No
significant change in VFT, ERP, or DFT occurred in the control group.
Conclusion: In this porcine model, the intravenous administration of
amiodarone increased VFT and ERP over 60 min after the injection,
without effect on DFT. (C) 2003 Elsevier Ireland Ltd. All rights
reserved.
Συγγραφείς:
Tsagalou, EP
Anastasiou-Nana, MI
Charitos, CE
Siafakas, CX
and Drakos, SG
Ntalianis, A
Terrovitis, JV
Mavrikakis, EM
and Doufas, A
Nanas, JN
