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Objective To investigate the effects of L-carnitine(L-CN)on electrophysiological changes induced by atrial ischemia in dogs.Methods Twelve dogs were divided into normal saline(NS)group and L-CN group.Atrial ischemia was induced by ligation of an atrial arterial branch of right coronary artery.Atrial effective refractory period(AERP)and conduction velocity(CV)of right atrium were measured before and after 3 hour's coronary artery ligation.Atrial wavelength(WL)and inducibility of atrial fibrillation(AF)were calculated.Histological examination was performed.Results (1)AERP and WL shortened dramatically after ligation of coronary artery in NS group;they showed no remarkable change in L-CN group.(2)There was no significant change of CV in the two groups.(3)AF was induced in 0 of 12 dogs under basic condition.(3)After ligation of the right coronary artery,AF was induced in all of the 6 dogs in NS group and 0 of 6 dogs in L-CN group.(5)Histological examination revealed that the ischemic changes occurred only in NS group.Conclusion Electrophysiological changes induced by atrial ischemia could be prevented by infusion of L-CN.
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OBJECTIVE: To evaluate the neurophysiological changes after intramuscular botulinum toxin A (BTX-A) injection in normal adults. METHOD: Nine subjects were studied by electrophysiological measurements before and after the injections. BTX-A (5 IU, Botox , Allergen, USA) was injected in the extensor digitorum brevis (EDB) muscles. Thereafter, electrophysiological measurement was followed up during 6 months. RESULTS: The compound muscle action potential (CMAP) amplitude of injected EDB muscle decreased significantly for 8 weeks, a maximal decrement at 4 weeks after injection. CMAP peak area changes over time were nearly identical to those of CMAP peak amplitudes. The first/fourth amplitude change of CMAP with 3-Hz repetitive nerve stimulation decreased significantly for 8 weeks and the amplitude following post-exercise activation increased significantly after injection. There were no significant changes in F-wave amplitude and latency. CONCLUSION: Serial electrophysiological measurements after intramuscular BTX-A injection into EDB provide useful information for the neurophysiological change after injection.