ABSTRACT
Objective To investigate the protective effects of Ulinastatin (UTI) and 1, 6 fructose diphosphate (FDP) on cerebral ischemia-reperfusion injury, and to discuss the protective mechanisms of UT1 and FDP on cerebral ischemia-repeffusion injury. Method Rabbit ischemia-repeffusion injury models were prepared by"four arteries occlusion". All rabbits were divided into four groups (n=6): control group, UTI (10 U/kg) group, FDP (200 mg/kg) group, UTI+ FDP group. Salt water, UTI, FDP and UTI + FDP were respectively used immediately after ischemia-reperfusion. Plasmic MDA and GSH-Px were measured at 30 minutes, 1 hour, 3 hours and 6 hours after reperfusion. Results The concentrations of plasmic MDA in every group were significantly improved compared with those in control group (P0.05 ), but significant difference could be found after 3 hours (P
ABSTRACT
<p><b>BACKGROUND</b>Right ventricular apical pacing has been reported to reduce cardiac performance. But there are few reports on the effects of dual chamber (DDD) pacing on cardiac function compared to sinus rhythm. In this study, we evaluated the effects of right atrial and ventricular DDD pacing on cardiac function and ventricular contraction synchrony using equilibrium radionuclide angiography.</p><p><b>METHODS</b>Ten patients implanted with a right atrial and ventricular DDD pacemaker underwent equilibrium radionuclide angiography. The scintigraphic data were obtained during sinus rhythm and pacing rhythm. Cardiac function parameters were obtained semimanually. Phase analysis was used to study the ventricular activation sequence and ventricular synchrony.</p><p><b>RESULTS</b>The left ventricular 1/3 ejection fraction decreased significantly during pacing compared with that during sinus rhythm [(23.4 +/- 6.1)% vs (27.7 +/- 4.5)%, P = 0.01]. Regional ejection fraction also decreased during pacing, although the difference was not statistically significant. Phase analysis showed that the right ventricle was activated earlier than the left ventricle during pacing, and that the phase shift was significantly greater during pacing than that during sinus rhythm [64.13 degrees +/- 16.80 degrees vs 52.88 degrees +/- 9.26 degrees, P = 0.007]. The activation of both ventricles occurred simultaneously during sinus rhythm, with the activation sequence from proximal septum or base of left ventricle to apex. The earliest activation during pacing occurred at the right ventricular apex, and subsequently spread to the base and left ventricle.</p><p><b>CONCLUSION</b>Right atrial and ventricular DDD pacing impairs left ventricular systolic function and ventricular synchrony.</p>