The Effect of 2-(o-Cresyl)-4H-1:3:2-benzodioxaphosphorin-2-oxide on Tissue Cholinesterase and Carboxylesterase Activities of the Rat

The dose-response (0.1 to 1000 mg/kg sc) effects of 2-(o-cresyl)-4H-l:3:2-benzodioxaphosphorin-2-oxide(CBDP; a melabolite of the organophosphorus compound tri-o-cresylphosphareon total cholinesterase (ChE) and carboxylesterase (CaE) activitiesin tissues from the rat were examined. Doses of CBDP greaterthan 1.0 mg/kg inhibited CaE activity maximally (>99%) inplasma and lung, two important sites for detoxification of organophosphorustoxicants. A biphasic dose-dependent inhibition of ChE activitywas seen in all tissues; the ED5O values showed a differenceof two orders of magnitude between the first and the secondphases of the dose-response curves. CBDP inhibited the bloodesterases in the order plasma CaE plasma ChE red blood cell(RBC) ChE. The biphasic dose-response curve and preferentialinhibition of the blood esterases may reflect the inhibitionof butyryicholinesterase in preference to acetylcholinesterasein these tissues. At doses of CBDP below 1.0 mg/kg, plasma,RBC, and brain regional ChE activities were inhibited by lessthan 10%, whereas at doses above 2.0 mg/kg, ChE activities wereinhibited substantially (up to 80% in plasma, up to 60% in RBC,and greater than 90% in brain regions). On the basis of theseresults, a dose of CBDP between 1.0 and 2.0 mg/kg should proveuseful as a pretreatment for studies of OP toxicity in the rat.     

A Prospective,Randomized Comparison of Modified Pulmonary Vein Isolation Versus Conventional Pulmonary Vein Isolation in Patients with Paroxysmal Atrial Fibrillation

Modified Pulmonary Vein Isolation in AF Ablation. Introduction: Pulmonary vein isolation (PVI) is the primary ablation therapy in patients with atrial fibrillation (AF). We hypothesized that high dominant frequency (DF) sites (AF nests during sinus rhythm [SR]) adjacent to the PV ostia are associated with the atrial substrate that maintains AF, and PVI incorporating the high‐frequency AF nests may have a higher efficacy. Methods and Results: In a prospective and randomized comparison, 126 symptomatic paroxysmal AF patients that underwent PVI were enrolled. We compared the efficacy of a modified PVI (ablation line: 1.0–1.5 cm from the PV ostium with encircling the AF nests [spectral analysis with DF >70 Hz during SR, Group II]) versus the anatomy‐guided conventional PVI (Group I). In Group II, the DF value along the PV ostium was lower than 70 Hz after the PVI. The primary endpoint was the freedom from symptomatic atrial arrhythmias after a single procedure. We also followed the autonomic function by a time‐domain analysis of the heart rate variability. In both groups, AF nests were observed and electric isolation was successfully obtained in all patients. With a mean duration of 16 ± 6.1 months of follow‐up, Group II had a higher single procedure efficacy without drugs (78.7% vs 66.1%, log‐rank test: P = 0.02), and fewer repeat procedures (6.6% vs 23%; P = 0.04), as compared to Group I. Conclusion: PVI incorporating the high frequency AF nests adjacent to the PV ostia had a better single procedure efficacy. (J Cardiovasc Electrophysiol, Vol. 23, pp. 1155–1162, November 2012)     

Electrophysiologic Characteristics and Anatomical Complexities of Accessory Atrioventricular Pathways with Successful Ablation of Anterograde and Retrograde Conduction at Different Sites

RF Ablation of Accessory Pathways. Introduction: Catheter ablation may eliminate anterograde and retrograde accessory pathway conduction at closely adjacent but anatomically discrete sites. However, the mechanisms of this discrepancy, the electrophysiologic and anatomical characteristics, and information about systematic study from a large patient population are not available. The purpose of this study was to investigate the electrophysiologic characteristics and anatomical complexities of the accessory pathway in which anterograde and retrograde conduction was successfully ablated at different sites. Methods and Results: Thirty-eight (10.9%) patients (19 men and 19 women; mean age 37 ± 2.4 years) fulfilling the criteria of having separate ablation sites for anterograde and retrograde conduction were designated as group I, and the other 310 patients (215 men and 95 women; mean age 47 ± 0.6 years) were designated as group II. The patients with right-sided free-wall pathways had the highest incidence (18.6%) of separate ablation sites. The anatomical distance between anterograde and retrograde directions (left anterior oblique view. 13 ± 0.6 vs 8 ± 0.9 mm, P < 0.01; right anterior oblique view, 17 ± 0.6 vs 5 ± 0.7 mm, P < 0.01), and incidence of conduction impairment in one direction after successful ablation of another direction (15% vs 78%, P < 0.05) differed significantly between left and right free-wall pathways. The mean distances obtained from left (7 ±0.4 vs 14 ± 0.4 mm, P < 0.05) and right (7 ± 1.1 vs 15 ± 0.9 mm, P < 0.05) anterior oblique views were shorter in patients who had impairment of conduction properties than those in patients without impaired conduction after successful ablation of one direction. Conclusions: This study showed that anatomical and functional dissociation of the accessory pathway into anterograde and retrograde components was possible. Further study on the relation between electropbysiologic and pathologic characteristics would be helpful to confirm these findings.     

EXTRAVASATION OF URINE A STUDY OF THIRTY CASES

Extravasation of urine is not an uncommon urological emergency. The paucity of accounts in Iiterature prompts us to place this rcport on record. Tlw report is based on a clinical study of thirty cases of extravasation of urine seen on the UrologiCail Scrvice of the Pciping Uniotl Medical College Hospital during the years, 1922-1932. The mechanism of the development of this condition is considered and treat- ment is discussed.     

Malfunction of an Active Fixation J-Shaped Screw-In Atrial Electrode Lead: A Case Report

Active fixation leads, using active grasping devices, ensure good postoperative lead fixation, long-term performance, and make possible later lead removal on demand. However, these delicate designs have not been without practical difficulties. We present two cases of fixation stylet fracture during helix extension and retraction maneuver respectively with resultant lead inoperability and abandonment. The fixed leads could be removed by torquing the entire lead counterclockwise.     

Gender Differences in the Clinical Characteristics and Atrioventricular Nodal Conduction Properties in Patients With Atrioventricular Nodal Reentrant Tachycardia

Gender Differences in Patients With AVNRT. Introduction: The detailed electrophysiological characteristics of the gender differences associated with atrioventricular nodal reentrant tachycardia (AVNRT) have not been clarified. This study investigated the gender‐related electrophysiological differences in a large series of patients undergoing radiofrequency catheter ablation. Methods and Results: A total of 2,088 consecutive AVNRT patients (men/women 869/1,219) who underwent catheter ablation were enrolled in this study. We evaluated the gender differences in their electrophysiological characteristics. Women had a significantly younger age of onset, higher incidence of multiple jumps, shorter AH interval, atrial effective refractory period (ERP), anterograde fast pathway ERP, anterograde slow pathway ERP, and retrograde slow pathway ERP, and longer ventricular ERP than men. The incidence of baseline ventriculoatrial dissociation was lower in women than in men. Women needed less isoproterenol/atropine to induce AVNRT. No gender differences in the radiation exposure time, procedure time, complication rate, acute success rate, or second procedure rate were noted. Both typical and atypical AVNRT were more predominant in women. In the patients with atypical AVNRT, there was no significant gender difference in incidence of baseline ventriculoatrial dissociation; however, the retrograde slow pathway ERP was significantly shorter in women than in men. Women of premenopausal age (≤50 years old) had a significantly higher incidence of anterograde multiple jumps and a retrograde jump phenomenon, and a shorter anterograde slow pathway ERP and retrograde slow pathway ERP than those of women over 50 years old. Conclusion: Gender differences in the anterograde and retrograde AV nodal electrophysiology were noted in the patients with AVNRT. (J Cardiovasc Electrophysiol, Vol. 21, pp. 1114‐1119)     

The Novel Electrophysiology of Complex Fractionated Atrial Electrograms: Insight from Noncontact Unipolar Electrograms

Unipolar Characteristics of CFAEs. Background: The noncontact mapping (NCM) system possesses the merit of global endocardial recording for unipolar and activation mapping. Objective: We aimed to evaluate the unipolar electrogram characteristics and activation pattern over the bipolar complex fractionated atrial electrogram (CFAE) sites during atrial fibrillation (AF). Methods: Twenty patients (age 55 ± 11 years old, 15 males) who underwent NCM and ablation of AF (paroxysmal/persistent = 13/7) were included. Both contact bipolar (32–300 Hz) and NCM virtual unipolar electrograms (0.5–300 Hz) were simultaneously recorded along with the activation pattern (total 223 sites, 11 ± 4 sites/patient). A CFAE was defined as a mean bipolar cycle length of ≤ 120 ms with an intervening isoelectric interval of more than 50 ms (Group 1A, n = 63, rapid repetitive CFAEs) or continuous fractionated activity (Group 1B, n = 59, continuous fractionated CFAEs), measured over a 7.2‐second duration. Group 2 consisted of those with a bipolar cycle length of more than 120 ms (n = 101). Results: The Group 1A CFAE sites exhibited a shorter unipolar electrogram cycle length (129 ± 11 vs 164 ± 20 ms, P < 0.001), and higher percentage of an S‐wave predominant pattern (QS or rS wave, 63 ± 13% vs 35 ± 13%, P < 0.001) than the Group 2 non‐CFAE sites. There was a linear correlation between the bipolar and unipolar cycle lengths (P < 0.001, R = 0.87). Most of the Group 1A CFAEs were located over arrhythmogenic pulmonary vein ostia or nonpulmonary vein ectopy with repetitive activations from those ectopies (62%) or the pivot points of the turning wavefronts (21%), whereas the Group 1B CFAEs exhibited a passive activation (44%) or slow conduction (31%). Conclusions: The bipolar repetitive and continuous fractionated CFAEs represented different activation patterns. The former was associated with an S wave predominant unipolar morphology which may represent an important focus for maintaining AF. (J Cardiovasc Electrophysiol, Vol. 21, pp. 640‐648, June 2010)