伊布利特对人体心房与心室电生理特性的影响

探讨伊布利特对人体右房、左房及右室有效不应期(RA-ERP、LA-ERP及RV-ERP)与房间、室间传导时间的影响。测定25例射频消融术后患者于静脉推注伊布利特(0.0167mg/kg)前后在基础起搏周长为600ms时的RA-ERP、LA-ERP及RV-ERP,同时测量起搏与窦性心律时的心房、心室传导时间。其中通过起搏冠状静脉窦远端间接起搏左房。结果:①伊布利特明显延长RA-ERP、LA-ERP及RV-ERP(P均<0.001)。②使用伊布利特后,对窦性心律时的P波宽度、PR间期、QRS时限、AH及HV均无明显影响(P>0.05),对房间及室间传导时间无明显影响(P>0.05),亦对急性期的起搏阈值无明显影响(P>0.05)。③使用伊布利特后2例出现右束支阻滞。结论:伊布利特可明显延长RA-ERP、LA-ERP及RV-ERP,但不影响房间、室间传导时间。     

伊布利特转复其他抗心律失常无效的室上性心动过速一例

1 病例资料 患者,女性,24岁,因阵发性心悸23年,再发1天入院。患者自出生后无诱因出现心悸、胸闷症状,每次发作10min至数小时不等,偶伴胸闷,可自行停止,1年前再发心悸时出现低血压,昏倒,在ICU抢救后好转出院,     

伊布利特的临床和电生理学研究进展

伊布利特是一种新型的Ⅲ类抗心律失常药物,临床主要用于心房颤动、心房扑动的转复,具有疗效显著、不良反应相对较小等优点,伊布利特的临床疗效优于普罗帕酮,与氟卡胺、胺碘酮疗效相近,伊布利特与普罗帕酮、胺碘酮、电复律、镁剂联用可提高临床疗效。     

伊布利特合用Ic类药物转复心房颤动/心房扑动的基础与临床

国外伊布利特已广泛应用于转复阵发性心房颤动/心房扑动,近年更有临床研究发现伊布利特与Ic类药物合用时,心房颤动/心房扑动转复成功率增加、而致严重心律失常与单用伊布利特时相当。现对伊布利特与Ic类药物合用的药理基础、临床试验结果及问题和展望等方面作一综述。     

伊布利特转复心房颤动的疗效及安全性评价

目的 评价伊布利特转复心房颤动的有效性和安全性.方法 入选31例持续时间＜90 d的阵发性和持续性心房颤动患者,15例静脉注射伊布利特进行转律,16例应用胺碘酮转律.比较两组药物转复心房颤动的成功率、转复时间和不良事件.结果 伊布利特组转复房颤的总成功率显著高于胺碘酮组(66.7与37.5％,x2=1.98,P＜0.05),伊布利特组的转复房颤时间明显缩短[(31.75±7.39) min与(51.87±9.26) min,t =3.67,P＜0.05],未发生有临床意义的药物致心律失常作用.结论 伊布利特转复阵发性和持续性心房颤动优于胺碘酮,并有良好的安全性.     

Acute beta-adrenoceptor blockade improves efficacy of ibutilide in conversion of atrial fibrillation with a rapid ventricular rate

Aims: Activation of beta-adrenoceptors attenuates prolongation ofaction potential duration induced by blockade of the delayedrectifier potassium current. We examined whether acute administrationof beta-blocker could enhance ibutilide (IB) efficacy in conversionof atrial fibrillation (AF) with a rapid ventricular rate. Methods and results: Ninety patients (aged 63 ± 13.5 years) with rapidly conductingAF were randomized in to two groups. Group A (n = 44) receivedesmolol titrated to achieve a heart rate of <100 bpm followedby IB co-administration, while Group B (n = 46) were treatedwith IB as monotherapy. In Group A, 29 patients (67%) convertedto sinus rhythm (SR) compared with 21 (46%) in Group B (P =0.04). The use of esmolol was the most important predictor forcardioversion (P = 0.009). The slower the heart rate at thetime of IB initiation, the higher the likelihood for cardioversion(P = 0.015). Patients in Group A had significantly shorter correctedQT interval (QTc) at the time of conversion than those in GroupB (433 vs. 501 ms, P = 0.003). Two patients in Group A developedsevere bradycardia, whereas three patients in Group B developedsevere ventricular tachycardia (VT). Conclusion: Compared with IB monotherapy, the combination therapy of esmololand IB appears to be more effective in conversion of rapidlyconducting AF back to SR. The addition of beta-blocker reducesQTc prolongation and diminishes the risk of VT at the expense,however, of increased bradycardic events.     

Effectiveness of Ibutilide in Cardioversion of Persistent Atrial Fibrillation in Patients with Dual Chamber Stimulation

Aim of the study: To evaluate the effectiveness of Ibutilide in cardioversion of persistent atrial fibrillation in patients with sinus node disease wearing a dual chamber pacemaker and to assess the potential role of overdrive ventricular pacing in prevention of drug related proarrhythmia. Methods and Results: Fifty-three sinus node disease patients (35 males; mean age 75 ± 9.5 years), implanted with a dual chamber pacing system, with persistent atrial fibrillation, lasting for 328 ± 416 days, received 1–2 mg of intravenous Ibutilide. Pacing mode was programmed in VVI at 90 ppm, in order to suppress spontaneous ventricular activity. All patients were monitored for 4 hours. Late occurrence of ventricular arrhythmias was evaluated using the pacemaker memory. Ventricular pacing threshold, spontaneous electrogram amplitude and pacing impedance were measured before and after Ibutilide infusion. Cardioversion to sinus rhythm occurred in twenty-two patients (41.5%). Treatment success was significantly related to shorter atrial fibrillation duration. Paced QT interval duration increased from 412 ± 36 ms to 481 ± 40 ms (p < 0.0001), without differences between responders and non responders; QRS width did not change significantly (from 152 ± 25 ms to 161 ± 25 ms; p = n.s.). No early or late episodes of sustained or non sustained polymorphic ventricular tachycardia were observed. Pacing and sensing threshold did not show any significant variation. Conclusions: Ibutilide showed a good effectiveness in treating persistent atrial fibrillation in paced patients. Overdrive ventricular pacing may have played a role in preventing drug induced ventricular proarrhythmia. No adverse effect on pacing threshold was observed.     

Enhancement of bupivacaine local anesthesia with the potassium channel blocker ibutilide.

In some clinical settings it is necessary to inject large volumes of local anesthetic--and consequently very high doses--in order to provide an adequate level of block. Subsequent absorption of these high doses, or inadvertent intravenous administration of even small doses, has led to systemic toxicity. Thus, it is desirable to develop adjuvants that are inert alone, but would enhance the potency and/or efficacy of local anesthetics to improve their safety. Adelta/C fibers possess K(+) channels identified as sustained delayed rectifier type K(DR) currents and transient A-type K(A) currents. In the heart, the class III antiarrhythmic drug ibutilide blocks the cardiac component of the rapid delayed rectifying K(+) current (IKr). Experiments were conducted to determine whether co-administration of the K(+) channel blocker ibutilide would enhance the local anesthetic bupivacaine in mice. After injecting bupivacaine mixed with vehicle or ibutilide in the popliteal region of mice, paw withdrawal latencies were determined by applying the plantar aspect of a single hind-paw to the surface a 55 degrees C hot-plate device. 0.5% Bupivacaine+ibutilide (7.8x10(-5) M) elicited significantly longer hot-plate latencies than 0.5% bupivacaine+vehicle. In addition, bupivacaine was 2.6-fold more potent when co-administered with ibutilide rather than vehicle. Epinephrine extends the tissue concentrations of local anesthetics by inducing localized vasoconstriction. Epinephrine augmented the enhancement by ibutilide of bupivacaine's potency by 6.8-fold. In summary, ibutilide may enhance the effects of bupivacaine by blocking K(+) channels on sensory nociceptive nerves.     

静脉注射伊布利特与胺碘酮转复消融术后复发房性心动过速的对比研究

目的观察和比较伊布利特和胺碘酮转复心房颤动（房颤）射频消融术后早期复发房性心动过速（房速）的疗效和安全性。方法连续46例接受房颤射频消融后复发房速的患者,男性32例,女性14例,平均年龄（56±12）岁,分别静脉应用伊布利特（ibutilide,1．0mg／次,1～2次,10min内静脉推注）和胺碘酮（150me,／次,1～2次,10min内静脉推注）。观察转复率和转复时间,记录不良反应。结果4h内伊布利特组和胺碘酮组转复率分别为86．4％和41．7％（P=0．0023）;24h时内转复率分别为90．9％和62．5％（P=0．0376）。伊布利特组对持续时间〈24h的房速转复率为100％,胺碘酮组转复率为66．7％（P=0．0421）。伊布利特组平均转复时间为（13±8）min,胺碘酮组转复时间为（364-25）min（P〈0．01）。两组均未发生致命性不良反应,不良反应发生率差异无统计学意义。结论伊布利特和胺碘酮均能终止射频消融术后复发房速,伊布利特更快速、安全、有效。