AIM: To examine the effect of ibutilide on novel indexes of repolarization in patients with persistent atrial fibrillation (AF). METHODS: We studied consecutive patients scheduled for elective electrical cardioversion...AIM: To examine the effect of ibutilide on novel indexes of repolarization in patients with persistent atrial fibrillation (AF). METHODS: We studied consecutive patients scheduled for elective electrical cardioversion. Intravenous ibutilide (1+1mg) was administered before the electrical cardioversion while close electrocardiographic (ECG) monitoring was performed. ECG indexes such as corrected QT interval (QTc), the interval from the peak until the end of T wave (Tpe), and the Tpe/QT ratio were measured before ibutilide infusion and 10 min after the end of infusion. RESULTS: The final study population consisted of 20 patients (mean age: 67.1±9.9 years, 10 men). Six patients were cardioverted pharmacologically and did not proceed to electrical cardioversion. Two patientsdeveloped short non-sustained episodes of torsades de pointes ventricular tachycardia. All but one of the aforementioned ECG indexes increased significantly after ibutilide administration. In specific, the QTc interval increased from 442 ± 29 to 471 ± 37 ms (P=0.037), the Tpe interval in precordial leads from 96 ms (range 80-108 ms) to 101 ms (range 91-119 ms) (P=0.021), the Tpe interval in lead Ⅱ from 79 ms (range 70-88 ms) to 100 ms (range 87-104 ms) (P<0.001), the Tpe/QT ratio in precordial leads from 0.23 ms (range 0.18-0.26 ms) to 0.26 ms (range 0.23-0.28 ms) (P=0.028), and the Tpe interval dispersion from 25 ms (range 23-30 ms) to 35 ms (range 27-39 ms) (P=0.012). However, the Tpe/QT ratio in lead II did not change significantly. CONCLUSION: Ibutilide increases the duration and dispersion of ventricular repolarization. The prognostic value of Tpe and Tpe/QT in the setting of drug-induced proarrhythmia needs further study.展开更多
Background Patients with persistent or permanent atrial fibrillation （AF） often need direct current cardioversion after radiofrequency ablation. The aim of this study was to investigate the effectiveness and safety ...Background Patients with persistent or permanent atrial fibrillation （AF） often need direct current cardioversion after radiofrequency ablation. The aim of this study was to investigate the effectiveness and safety of ibutilide for cardioversion of persistent or permanent atrial fibrillation after radiofrequency ablation and the factors related to conversion. Methods Patients with persistent or permanent atrial fibrillation were treated with combined ablation strategy including circumferential pulmonary vein isolation, linear ablation and CAFE potential ablation. If AF was not terminated after ablation, ibutilide was used for cardioversion （1 mg, intravenous injection in 10 minutes）. These patients were divided into a conversion group and a non-conversion group according to whether AF was converted to sinus rhythm within 30 minutes after administration. ECG monitoring was performed during the injection of ibutilide. Atrial waves recorded by coronary sinus electrodes were measured for calculating average wavelength of AF waves in six seconds. The QT interval was measured immediately after conversion and 2 hours after injection of ibutilide.Results Forty patients whose AF was not converted to sinus rhythm after radiofrequency ablation were given an intravenous injection of ibutilide. Of the 40 patients, 29 cases were converted to sinus rhythm, with a conversion rate of 72.5%. The average conversion time was （13.2±5.5） minutes. Compared with the conversion group, patients in the non-conversion group had a longer history of AF （9.4±5.3） years vs. （4.3±2.8） years, P 〈0.05）, and a markedly enlarged left atrium （47.3±2.9） mm vs. （42.1±4.5） mm, P〈0.05）. There were no significant differences in gender, age, body mass index and left ventricular function between the two groups. Ibutilide significantly prolonged the average wavelength of the AF wave （171.8±29.5） ms vs. （242.0±40.0） ms, P 〈0.001）. Two hours after ibutilide treatment, the QT interval was significantly shortened （421.0±24.7） ms vs. （441.0±37.4） ms, P〈0.05）. No cases of serious arrhythmias or other adverse reactions were found.Conclusions A single dose of ibutilide for conversion of persistent or permanent AF after radiofrequency ablation is safe and effective.展开更多
Background Ibutilide has been commonly used for pharmacologic cardioversion of atrial fibrillation and flutter in clinical settings. The objective of this study was to investigate the effects of ibutilide on the defib...Background Ibutilide has been commonly used for pharmacologic cardioversion of atrial fibrillation and flutter in clinical settings. The objective of this study was to investigate the effects of ibutilide on the defibrillation threshold （DFT）, restitution properties, dispersion of refractoriness and activation patterns during ventricular fibrillation （VF）. Methods Ibutilide was administrated intravenously in six open-chest beagles. Before and after the drug administration, 20-second episodes of VF were electrically induced and recorded with a 10×10 unipolar electrode plaque sutured on the lateral epicardium of the left ventricle. DFT and VF activation patterns, including type of epicardial activation maps, VF cycle length （VF-CL）, conduction velocity, wavelength （WL） and reentry incidence, were measured. Restitution properties and dispersion of refractoriness were estimated from activation recovery intervals （ARI） during pacing. Results Compared to baseline, ibutilide markedly decreased the DFT by 31% （（491±14） V vs. （337±59） V, P 〈0.01）. The drug significantly reduced the maximal slope of the restitution curve （1.34±0.08 vs. 0.76±0.06, P 〈0.01） and its epicardial dispersion （0.36±0.09 vs. 0.21±0.06, coefficient of variation, P=0.03）. The dispersion of refractoriness was enhanced at the pacing cycle length of 300 ms to 160 ms by ibutilide. The drug significantly increased the VF-CL （（96±19） ms vs. （112±20） ms, P 〈0.01） and the WL （（41±9） mm vs. （52±14） mm, P=0.02） during VF, and reduced the reentry incidence by 25% （0.08±0.02 vs. 0.06±0.02, P 〈0.01）. In the epicardial activation maps, ibutilide significantly reduced the percentage of more complex activation maps during VF. Conclusions Intravenous ibutilide significantly decreased the DFT. It might be due to reduction of activation pattern complexity during VF.展开更多
文摘AIM: To examine the effect of ibutilide on novel indexes of repolarization in patients with persistent atrial fibrillation (AF). METHODS: We studied consecutive patients scheduled for elective electrical cardioversion. Intravenous ibutilide (1+1mg) was administered before the electrical cardioversion while close electrocardiographic (ECG) monitoring was performed. ECG indexes such as corrected QT interval (QTc), the interval from the peak until the end of T wave (Tpe), and the Tpe/QT ratio were measured before ibutilide infusion and 10 min after the end of infusion. RESULTS: The final study population consisted of 20 patients (mean age: 67.1±9.9 years, 10 men). Six patients were cardioverted pharmacologically and did not proceed to electrical cardioversion. Two patientsdeveloped short non-sustained episodes of torsades de pointes ventricular tachycardia. All but one of the aforementioned ECG indexes increased significantly after ibutilide administration. In specific, the QTc interval increased from 442 ± 29 to 471 ± 37 ms (P=0.037), the Tpe interval in precordial leads from 96 ms (range 80-108 ms) to 101 ms (range 91-119 ms) (P=0.021), the Tpe interval in lead Ⅱ from 79 ms (range 70-88 ms) to 100 ms (range 87-104 ms) (P<0.001), the Tpe/QT ratio in precordial leads from 0.23 ms (range 0.18-0.26 ms) to 0.26 ms (range 0.23-0.28 ms) (P=0.028), and the Tpe interval dispersion from 25 ms (range 23-30 ms) to 35 ms (range 27-39 ms) (P=0.012). However, the Tpe/QT ratio in lead II did not change significantly. CONCLUSION: Ibutilide increases the duration and dispersion of ventricular repolarization. The prognostic value of Tpe and Tpe/QT in the setting of drug-induced proarrhythmia needs further study.
文摘Background Patients with persistent or permanent atrial fibrillation （AF） often need direct current cardioversion after radiofrequency ablation. The aim of this study was to investigate the effectiveness and safety of ibutilide for cardioversion of persistent or permanent atrial fibrillation after radiofrequency ablation and the factors related to conversion. Methods Patients with persistent or permanent atrial fibrillation were treated with combined ablation strategy including circumferential pulmonary vein isolation, linear ablation and CAFE potential ablation. If AF was not terminated after ablation, ibutilide was used for cardioversion （1 mg, intravenous injection in 10 minutes）. These patients were divided into a conversion group and a non-conversion group according to whether AF was converted to sinus rhythm within 30 minutes after administration. ECG monitoring was performed during the injection of ibutilide. Atrial waves recorded by coronary sinus electrodes were measured for calculating average wavelength of AF waves in six seconds. The QT interval was measured immediately after conversion and 2 hours after injection of ibutilide.Results Forty patients whose AF was not converted to sinus rhythm after radiofrequency ablation were given an intravenous injection of ibutilide. Of the 40 patients, 29 cases were converted to sinus rhythm, with a conversion rate of 72.5%. The average conversion time was （13.2±5.5） minutes. Compared with the conversion group, patients in the non-conversion group had a longer history of AF （9.4±5.3） years vs. （4.3±2.8） years, P 〈0.05）, and a markedly enlarged left atrium （47.3±2.9） mm vs. （42.1±4.5） mm, P〈0.05）. There were no significant differences in gender, age, body mass index and left ventricular function between the two groups. Ibutilide significantly prolonged the average wavelength of the AF wave （171.8±29.5） ms vs. （242.0±40.0） ms, P 〈0.001）. Two hours after ibutilide treatment, the QT interval was significantly shortened （421.0±24.7） ms vs. （441.0±37.4） ms, P〈0.05）. No cases of serious arrhythmias or other adverse reactions were found.Conclusions A single dose of ibutilide for conversion of persistent or permanent AF after radiofrequency ablation is safe and effective.
基金This study was supported by grants from the National Natural Science Foundation of China （No. 81070266 and No. 81000081） Shanghai Science and Technology Committee （No. 10140903100 and No. 11ZR1422800） Program for Innovative Research Team of Shanghai Municipal Education Commission.
文摘Background Ibutilide has been commonly used for pharmacologic cardioversion of atrial fibrillation and flutter in clinical settings. The objective of this study was to investigate the effects of ibutilide on the defibrillation threshold （DFT）, restitution properties, dispersion of refractoriness and activation patterns during ventricular fibrillation （VF）. Methods Ibutilide was administrated intravenously in six open-chest beagles. Before and after the drug administration, 20-second episodes of VF were electrically induced and recorded with a 10×10 unipolar electrode plaque sutured on the lateral epicardium of the left ventricle. DFT and VF activation patterns, including type of epicardial activation maps, VF cycle length （VF-CL）, conduction velocity, wavelength （WL） and reentry incidence, were measured. Restitution properties and dispersion of refractoriness were estimated from activation recovery intervals （ARI） during pacing. Results Compared to baseline, ibutilide markedly decreased the DFT by 31% （（491±14） V vs. （337±59） V, P 〈0.01）. The drug significantly reduced the maximal slope of the restitution curve （1.34±0.08 vs. 0.76±0.06, P 〈0.01） and its epicardial dispersion （0.36±0.09 vs. 0.21±0.06, coefficient of variation, P=0.03）. The dispersion of refractoriness was enhanced at the pacing cycle length of 300 ms to 160 ms by ibutilide. The drug significantly increased the VF-CL （（96±19） ms vs. （112±20） ms, P 〈0.01） and the WL （（41±9） mm vs. （52±14） mm, P=0.02） during VF, and reduced the reentry incidence by 25% （0.08±0.02 vs. 0.06±0.02, P 〈0.01）. In the epicardial activation maps, ibutilide significantly reduced the percentage of more complex activation maps during VF. Conclusions Intravenous ibutilide significantly decreased the DFT. It might be due to reduction of activation pattern complexity during VF.
