ABSTRACT
Objective: To observe the effect of ivabradine (IVA) on atrial and ventricular monophasic action potential duration (MAPD) and its proarrhythmic action at presence of sea anemone toxin-II (ATX-II) in isolated rabbit heart modelin vitro. Methods: The perfusion of isolated heart from female New Zealand white rabbit was conducted by Langendorff method in vitro. Left atrial and left ventricular endo- , epi-cardial action potential were recorded when pacing with ifxed frequency of 350 ms (in correspondence with the heart rate of 171 times/min) to observe the effect of IVA alone and ATX-II (3 nmol/L) with IVA on MAPD90. In addition, to observe the action of IVA alone and ATX-II with IVA on proarrhythmia when IVA reducing the heart rate to autonomous cardiac rhythm as (156±10) times/min. Results: IVA at (3-10) μmol/L prolonged atrial and ventricular endo- , epi-cardial MAPD90 by (15.9 ± 2.0) ms, (31.5 ± 4.0) ms and (23.9 ± 3.0) ms (n=6,P<0.01), respectively. ATX-II at 3 nmol/L prolonged atrial and ventricular MAPD90 by (36.5 ± 5.0)ms and (19.9 ± 3.0) ms, (19.5 ± 4.0) ms (n=6,P<0.01) respectively. With ATX-II treatment, IVA at (6-10) μmol/L decreased atrial MAPD90 by (14.4 ± 4.0) ms (n=6,P<0.01), it induced atrial arrhythmia. With 3 nmol/L of ATX-II treated ventricle, IVA at (3-10) μmol/L obviously prolonged endo- and epi-cardial MAPD90 by (36.2 ± 7.0) ms and (27.5 ± 5.0) ms(n=6,P<0.01), respectively. IVA didn’t increase ventricular beat-to-beat variability and transmural dispersion of MAPD90 no matter with or without ATX-II treatment, no ventricular arrhythmia occurred. Conclusion: IVA prolongs both atrial and ventricular MAPD, with increased late sodium current, IVA may induce atrial arrhythmia but not ventricular arrhythmia in experimental rabbits in vitro.
ABSTRACT
Objective To analyze the risk factors of voiding dysfunction after mid-urethral sling surgery for stress urinary incontinence.Methods Clinical data of 573 consecutive patients undergoing midurethral sling surgery from January 2003 to December 2010 were collected and analyzed retrospectively.All relative risk factors were evaluated by univariate and multivariate Logistic analysis to identify risk factors of voiding dysfunction.Results Voiding dysfunction occurred in 28 patients,with an incidence of 4.9％ (28/573).Univariate analysis showed that age,previous pelvic surgery,pre-operative postvoid residuals,maximum flow rate,average urine flow rate,Valsalva leak point pressure,concomitant anterior pelvic repair and operator performing＜50 procedures were the relative risk factors (P＜0.05) for voiding dysfunction.Multivariate logistic regression analysis revealed that the maximum flow rate (Qmax) ≤ 15 ml/s (OR=3.782,P=0.003) was an independent risk factor for voiding dysfunction and surgery experience was its protection factors (OR=0.295,P=0.016).Conclusions Qmax ≤ 15 ml/s on preoperative urodynamic study is an independent risk factor for voiding dysfunction after mid-urethral sling procedure.Improving skill of surgery and strengthening technical training will help to reduce the incidence of this complication.