Analysis of clinical and electrophysiological characteristics of children with Wolff-Parkinson-White syndrome or ventricular pre-excitation / 中华实用儿科临床杂志

Objective@#To summarize the clinical and electrophysiological characteristics of children with Wolff-Parkinson-White syndrome or ventricular pre-excitation.@*Methods@#One hundred and seventy-nine consecutive children with Wolff-Parkinson-White syndrome or ventricular pre-excitation who were hospitalized at Beijing Anzhen Hospital Affiliated to Capital Medical University and planned to accept radiofrequency ablations were selected.Electrocardiogram and echocardiography were completed and detailed clinical data were collected before ablations.Anterograde refractory period of accessory pathways (ERPAPA) and retrograde ventriculoatrial conduction were measured during electrophysiology studies.The clinical and electrophysiological characteristics of these children were analyzed.@*Results@#The ratio of left-sided to right-sided accessory pathways was 1.001.93(61 cases vs.118 cases). Six out of 61 patients with left-sided accessory pathways were verified by electrophysiology study.There was no statistical difference of P-R interval and QRS duration between patients with right-sided and left-sided accessory pathways(all P>0.05). Twelve patients were combined with congenital heart diseases.Fourteen patients with right-sided accessory pathways were of ventricular pre-excitation induced dilated cardiomyopathy.ERPAPA was measured successfully in 110 patients, ERPAPA less than 250 ms accounted for 32.7%(36/110 cases). Six children with two pathways were recognized.Antidromic atrioventricular reentrant tachycardia was induced in 3 children.One child had slow conduction pathway localized in right-sided septum.@*Conclusions@#Right-sided overt accessory pathways are more common in children with Wolff-Parkinson-White syndrome or ventricular pre-excitation.Organic heart diseases are not uncommon.Besides congenital heart disease, a small proportion of patients with right overt accessory pathways may develop ventricular pre-excitatory induced dilated cardiomyopathy resulting from ventricular wall dyskinesia.Most of the decremental retrograde ventriculoatrial conduction is the characteristic of ventricular muscles rather than the accessory pathways in nature.Two pathways are not uncommon in children with Wolff-Parkinson-White syndrome or ventricular pre-excitation.Before finishing radiofrequency ablation, the anterograde and retrograde function of the accessory pathway should be evaluated in detail again because it is easy to neglect the existence of another accessory pathway.

Effects of selectively resecting the lower half of stellate ganglion on fast ventricular rate in canines with persistent atrial fibrillation / 中国胸心血管外科临床杂志

@#Objective To determine the effects of resecting the lower half of left stellate ganglion (LSG) on fast ventricular rate (VR) in persistent atrial fibrillation (AF) and its mechanism. Methods Twelve mature healthy male beagle dogs (15–25 kg) were studied. They were randomly divided into two groups (an experimental group and a control group, 6 dogs in each group). The control group were merely performed with rapid left atrial pacing to induce persistent AF. The experimental group were disposed with rapid left atrial pacing and received resection of the lower half of LSG after the persistent AF was documented. Simultaneously the ventricular rates were monitored separately before anesthesia, after anesthesia, 30 minutes and one month after LSG resection. The forward passing effective refractory period (ERP) of the canine atrioventricular node (AVN) was also measured. Results Each dog was documented with persistent AF after 3–6 weeks’ left atrial pacing. After resecting the lower half of LSG for 30 minutes (the control group was only observed for 30 minutes without LSG resection), the average VR of the control group attained 144.5±4.2 beats/min, while that of the experimental group was 121.5±8.7 beats/min (P<0.001). After resecting the lower half of LSG for one month (the control group was observed for one month without LSG resection), the average VR of the control group was 139.2±5.6 beats/min, while that of the experimental group was 106.5±4.9 beats/min (P<0.001). Meantime, the forward passing ERP of AVN of the experimental group was significantly prolonged than that of the control group (265.6±7.8 msvs.251.1±4.6 ms, P=0.003). Conclusion Resection of the lower half of LSG is efficient in reducing VR in canines with persistent AF, one of the mechanisms of which may be prolonging the forward passing ERP of AVN.

Visual Dominance Effect upon Passing the Central Bottleneck of Information Processing / 中华医学杂志(英文版)

Background@#In the classical psychological refractory period (PRP) paradigm, two stimuli are presented in brief succession, and participants are asked to make separate speeded responses to both stimuli. Due to a central cognitive bottleneck, responses to the second stimulus are delayed, especially at short stimulus-onset asynchrony (SOA) between the two stimuli. Although the mechanisms of dual-task interference in the classical PRP paradigm have been extensively investigated, specific mechanisms underlying the cross-modal PRP paradigm are not well understood. In particular, it remains unknown whether the dominance of vision over audition manifests in the cross-modal PRP tasks. The present study aimed to investigate whether the visual dominance effect manifests in the cross-modal PRP paradigm.@*Methods@#We adapted the classical PRP paradigm by manipulating the order of a visual and an auditory task: the visual task could either precede the auditory task or vice versa, at either short or long SOAs. Twenty-five healthy participants took part in Experiment 1, and thirty-three new participants took part in Experiment 2. Reaction time and accuracy data were calculated and further analyzed by repeated-measures analysis of variance.@*Results@#The results showed that visual precedence in the Visual-Auditory condition caused larger impairments to the subsequent auditory processing than vice versa in the Auditory-Visual condition: a larger delay of second response was revealed in the Visual-Auditory condition (135 ± 10 ms) than the Auditory-Visual condition (88 ± 9 ms). This effect was found only at the short SOAs under the existence of the central bottleneck, but not at the long SOAs. Moreover, this effect occurred both when the single visual and the single auditory task were of equal difficulty in Experiment 1 and when the single auditory task was more difficult than the single visual task in Experiment 2.@*Conclusion@#Results of the two experiments suggested that the visual dominance effect occurred under the central bottleneck of cognitive processing.

Investigations on effect of taurine-magnesium coordination compound against SQT2 in isolated hearts of guinea pig / 中国药理学通报

Aim To investigate the effect of taurine-magnesium coordination compound (TMCC) on elec-trocardiogram of isolated guinea pig hearts, hoping to describe a primary research on its characteristic of anti-short QT syndrome. Methods The isolated guinea pig heart was retrograde perfused using Langendorff tech-nique. In order to determine the effects of TMCC on QT interval, transmural dispersion of repolarization, effective refractory period, instability of RR interval and instability of QT interval in the presence of potassi-um channel opener pinacidil, the electrocardiogram of isolated guinea pig hearts was recorded using Biopac physiological recorder. Results The shortened QT in-terval and the effective refractory period induced by pinacidil could be prolonged by TMCC; the increased transmural dispersion of repolarization induced by pinacidil could be decreased by TMCC; the increased instability of RR and QT interval induced by pinacidil could be decreased by TMCC. Conclusion TMCC has the effects of anti-SQT2 by prolonging the QT inter-val and the effective refractory period, reducing the transmural dispersion of repolarization and instability.

Influence of circumferential pulmonary vein isolation on atrial effective refractory period in patients with paroxysmal atrial fibrillation / 中国介入心脏病学杂志

Objective To investigate the effects of circumferential pulmonary vein isolation (CPVI) on atrial effective refractory period (ERP) in patients with paroxysmal atrial fibrillation.Methods 30 patients who underwent radiofrequency catheter ablation for paroxysmal AF were enrolled in this study.Using FAM mode,the RA and LA anatomical models were achieved in the CARTO 3 system.SVC,MRA,RAA,LA-A,LA-R,LA-P,LAA,LSPV,LIPV,RSPV,RIPV,CSp,CSd,were respectively located in the RA or LA anatomical model.Before and after CPVI,ERPs were measured in different locations of the atrium using programmed stimulation.The ERPs of the RA (SVC,MRA,RAA,CSp),LA (LA-A,LA-R,LA-P,LAA,CSd),PVs (LSPV,RSPV,LIPV,RIPV) were compared.Bilateral CPVIs were completed in all patients,and PV-LA bidirectional conduction block was achieved.The changes of electrophysiological characteristics of atrium before and after CPVI were observed.Results (1) ERP at different locations in the atrium before CPVI:Comparisons of ERPs at different locations of atrium:RAA had the minimal ERPs[(197.4 ± 28.6) ms (P ＜ 0.01);followed by PVs measuring,respectively,LSPV (213.0 ± 47.5) ms,LIPV (208.9 ± 45.9) ms,RSPV (209.3 ± 43.6) ms,RIPV (213.5 ± 48.1) ms and LAA (218.1 ± 27.7) ms.Comparisons of ERPs in RA,LA,and PVs showed:PVs had the lowest ERPs (211.2 ± 35.2) ms versus RA ERP (227.0 ± 23.7) ms versus LA ERP (241.0 ± 21.5) ms (P ＜ 0.05).(2) Comparisons of ERPs before and after CPVI:Comparisons of ERPs at different locations of atrium showed:RAA [(197.4 ± 28.6) ms vs.(208.6 ± 32.2) ms,P=0.003],CSp [(234.7 ± 29.1) ms vs.(246.9 ± 29.7) ms,P=0.007],LA-R [(242.9 ± 28.9) ms vs.(258.3 ± 26.9) ms,P=0.003],LA-P [(252.2 ± 28.5) ms vs.(261.1 ± 30.2) ms,P=0.039]and CSd [(238.6 ± 28.3) ms vs.(250.3 ± 23.6) ms,P =0.009].ERPs were found statistically prolonged at all different locations after CPVI.Comparisons of ERPs at RAand LA after CPVI showed:RA [(227.0 ± 23.7) ms vs.(235.9 ± 21.7)ms,P=0.002]and LA [(241.0 ± 21.5) ms vs.(249.7 ± 19.9) ms,P =0.001],which were statistically increased after CPVI.(3) A total of 90 episodes of atrial arrhythmias were induced before CPVI which were found at RAA (n =17),LAA (n =12),and PVs (n =36).After CPVI,8 episodes of atrial arrhythmias were induced which were found at,RAA (n =4),LAA (n =3),and SVC (n =1).Conclusions (1) Compared with other parts of atrium,ERPs at PVs,LAA and RAA are significantly shorter in patients with paroxysmal AF.At PVs,LAA and RAA,atrial arrhythmias are easily to be induce by programmed stimulation.(2) In patients with paroxysmal Af:PVs has the shortest ERPsfollowed by RAs whereas LA ERPs is the longest.There is a large ERP gradient change between PVs and LA.(3) The ERPs at RAs,LAs,As,and LA-PV are prolonged after CPVI.(4) Atrial arrhythmia is less likely to be induced after CPVI.

Processing order in dual-tasks when the duration of motor responses varies / Orden de ejecución de dos tareas cuando la duración de las respuestas motoras varían

Recent studies reported that central processing duration influences processing order of two tasks in the psychological refractory period (PRP) paradigm. This study examined whether the duration of response execution influences the processing of task order. For this purpose, a tone discrimination task was combined with a letter discrimination task. Both tasks were presented in random order using different stimulus onset asynchronies (SOAs). In one condition, participants responded to each stimulus with a single key press (easy response condition). In the other condition, the tone task required a single key press, whereas the letter task required a more time-consuming key press-sequence (hard response condition). The results showed that participants tend to perform the tone task first more often when the response requirement for the letter task is hard, rather than easy. This result is consistent with the notion that participants optimize response scheduling in dual-task situations.

Bajo el paradigma de periodo refractario psicológico (PRP), recientes estudios han hallado que la duración del procesamiento central influye en el orden en el que dos tareas son procesadas. En el presente trabajo se examinó si la duración de la respuesta también influye en el orden en el que dos tareas se ejecutan. Para este propósito, se utilizó una tarea de discriminación auditiva en combinación con una tarea de discriminación visual. En el experimento se varió el orden de presentación de las tareas de forma aleatoria así como se utilizaron diferentes intervalos entre estímulos (stimulus onset asynchrony; SOA) En una condición, los participantes respondieron a cada estímulo pulsando una tecla (condición de respuesta simple). En la otra condición, mientras que a la tarea auditiva se respondía de nuevo pulsando una tecla, la respuesta a la tarea visual requería pulsar una secuencia de teclas, aumentando la duración de la respuesta (condición de respuesta compleja). Los resultados mostraron que los participantes tienden a ejecutar más a menudo la tarea auditiva en primer lugar cuando la respuesta de la tarea visual es más compleja. Este resultado apoya la noción de que, en escenarios de doble tarea, los participantes pueden invertir sus respuestas si con ello optimizan su ejecución.

Effect of local radiofrequency denervation on ventricular effective refractory period and ventricular arrhythmia susceptibility after acute myocardial infarction / 第二军医大学学报

Objective To introduce a new method of local denervation by ablation and to observe its effect on ventricular effective refractory periods and ventricular arrhythmia susceptibility after acute myocardial infarction. Methods Eighteen mongrel dogs were used to make myocardial infarction model by ligation of the 1st diagonal artery. Then local denervation was achieved by using six radiofrequency ablations (each at 8 W for 2 min) along the left anterior descending artery. Effective refractory periods were tested at six sites on the left ventricular epicardium (above, in and below the infarction areas, 2 sites each area) before and after local denervation by S1S2 stimulation. Ventricular arrhythmia was also induced after myocardial infarction and after denervation by burst pacing, and the number of arrhythmia episodes was recorded. Results The effective refractory periods were significantly prolonged after ablation ([191. 3±24. 9] ms vs [209. 0±27. 2] ms, P<0. 05). And the prolongation of effective refractory periods in infarcted area ([11. 3±8. 8] ms) was significantly shorter than those in the other 2 areas ([23. 2±10. 2] ms and [18. 7±11. 5] ms). After ablation, 8 of the 11 susceptible dogs were free of induced ventricular arrhythmia, while 3 of them were still inducible by burst pacing. The induced ventricular arrhythmia rate was reduced from 61.1% (11/18) to 16.7 %(3/18) (P = 0. 007). Conclusion The method in this study is promising for preventing ventricular arrhythmia in patientswith acute myocardial infarction receiving percutaneous coronary intervention.

La electrofisiología del Wolff-Parkinson-White en el paciente asintomático con actividad o riesgo profesional alto / The electrophysiology of Wolff-Parkinson-White in the asymptomatic patient with activity or with high professional risk

Objetivo: Describir las características electrofisiológicas en individuos con Wolff-Parkinson-White asintomático con actividad deportiva o alta responsabilidad profesional. Métodos: Se evaluaron 19 individuos, edad media 33 ± 13 años (grupo A). Las características electrofisiológicas fueron comparadas con un grupo control similar con WPW sintomático (grupo B). Resultados: En estado basal el periodo refractario anterógrado y la conducción anterógrada 1:1 sobre el fascículo accesorio fueron más largos en el grupo A (300 ± 48 ms vs 262 ± 32 ms, p < 0.05) y (355 ± 108 ms vs 307 ± 86 ms, p < 0.05), respectivamente. Ningún individuo del grupo A tuvo un periodo refractario anterógrado < 250 ms; y 58% no tuvieron conducción retrógrada sobre el fascículo accesorio vs 4% del grupo B (p< 0.001). La inducción de taquicardia fue significativamente menor (5.2%) en el grupo A vs grupo B (95%) (p < 0.001). Se indujo fibrilación auricular (FA) sólo en uno del grupo A vs en 32% grupo B (p< 0.001). Conclusión: Se confirman las características electrofisiológicas benignas en individuos asintomáticos comparados con sintomáticos. La deficiente conducción anterógrada junto con ausencia de conducción retrógrada explica la baja frecuencia de taquiarritmias y no apoyaría la investigación rutinaria en toda la población asintomática, pero debido a las posibles consecuencias, se mantiene la indicación sistemática con fines de ablación preventiva en el subgrupo de individuos asintomáticos con actividad deportiva o alta responsabilidad profesional.

Objective: Describe the electrophysiological characteristics in subjects with asymptomatic Wolff-Parkinson-White with sports activities or high professional responsibility. Methods: Nineteen subjects, mean age 33 ± 13 years (group A). The electrophysiological characteristics were compared with a matched group with symptomatic WPW (group B). Results: At baseline the anterograde refractory period and the anterograde conduction 1:1 over the accessory pathway were longer in group A (300 ± 48 ms vs 262 ± 32 ms, p <0.05 and 355 ± 108 ms vs 307 ± 86 ms, p <0.05), respectively. None of group A had a anterograde refractory period < 250 ms and 58% showed absence of retrograde conduction over the accessory pathway vs 4% of group B (p < 0.001). Induction of tachycardia was significantly less in group A (5%) than in group B (92%) (p < 0.001). Atrial fibrillation was induced in only one of group A vs 32% of group B (p< 0.001). Conclusion: We confirm the benign electrophysiological characteristics in asymptomatic compared to symptomatic subjects. Poor anterograde conduction along with absence of retrograde conduction explains the low frequency of tachyarrhythmias and would not support the routine investigation of all asymptomatic subjects. But, due to possible consequences, remains the systematic indication for preventive ablation in the subgroup of asymptomatic subjects with sporting activities or high professional responsibility.

Effect of left superior pulmonary vein fat pad on atrial fibrillation in dogs / 第二军医大学学报

Objective To explore the effect of ablation of left superior pulmonary vein fat pad(LSPV-FP) on atrial fibrillation(AF). Methods Twelve healthy adult mongrel dogs were anesthetized and ventilated; both cervical vagosympathetic trunks were exposed for stimulation. Thoracotomies at the 4th intercostal space of left and right chest were performed to expose the LSPV-FP. The effective refractory period(ERP)/ERP-dispersion (dERP) of atrium and LSPV, AF inducibility, and the ventricular rate of AF were measured in the following statuses: baseline, vagosympathetic trunk stimulation(VTS), LSPV-FP ablation, and VTS post LSPV-FP ablation. Results At baseline status, stimulation of the left or right vagosympathetic trunks significantly shortened the ERP of atrial ([84.44±29.50] ms vs [129.7±15.83] ms, [85.42±26.11] ms vs [129.7±15.83] ms, P<0.05), increased the dERP of atrial ([71.67±14.03] ms vs [34.17±18.32] ms, [57.5±24.17] ms vs [34.17± 18.32] ms, P<0.05), the difference of ERP between proximal and distal of LSPV(P<0.05), AF inducibility ([5.33± 1.231] times vs [0.75±0.96] times, [4.67±1.155] times vs [0.75±0.96] times, P<0.05), and deceased the ventricular rate of AF([143.6±22.42] beats/min vs [226.3±28.50] beats/min, [146.4±30.72] times/min vs [226.3±28.50] times/ min, P<0.05). LSPV-FP ablation significantly attenuated all the above electrophysiological changes induced by left VTS(P< 0.05), but showed no effects on those induced by right VTS. Conclusion Left vagosympathetic trunk plays an important role in the development and maintenance of AF partially through LSPV-FP.

Effect of left superior pulmonary vein fat pad on atrial fibrillation in dogs / 第二军医大学学报

Objective Toexplore the effect of ablation of left superior pulmonary vein fat pad (LSPV-FP) on atrial fibrillation(AF). Methods Twelve healthy adult mongrel dogs were anesthetized and ventilated; both cervical vagosympathetic trunks were exposed for stimulation. Thoracotomies at the 4th intercostal space of left and right chest were performed to expose the LSPV-FP. The effective refractory period(ERP)/ERP-dispersion (dERP) of atrium and LSPV, AF inducibility, and the ventricular rate of AF were measured in the following statuses: baseline, vagosympathetic trunk stimulation(VTS), LSPV-FP ablation, and VTS post LSPV-FP ablation. Results At baseline status, stimulation of the left or right vagosympathetic trunks significantly shortened the ERP of atrial ([84. 44±29.50] ms vs [129. 7± 15. 83] ms, [85. 42±26. 11] ms vs [129. 7± 15. 83] ms, P<0. 05), increased the dERP of atrial ([71. 67 ± 14. 03] ms vs [34. 17 ± 18. 32] ms, [57. 5 ± 24. 17] ms vs [34. 17 ± 18.32] ms, P<0. 05), the difference of ERP between proximal and distal of LSPV(P<0. 05), AF inducibility ([5. 33± 231] times vs [0. 75±0. 96] times, [4. 67± 1. 155] times vs [0. 75±0. 96] times, P<0. 05), and deceased the ventricular rate of AF([143. 6±22. 42] beats/min vs [226. 3±28. 50] beats/min, [146. 4±30. 72] times/min vs [226. 3±28. 50] times/ min, P<0. 05). LSPV-FP ablation significantly attenuated all the above electrophysiological changes induced by left VTS(P< 0. 05), but showed no effects on those induced by right VTS. Conclusion Left vagosympathetic trunk plays an important role in the development and maintenance of AF partially through LSPV-FP.

Implante coclear: correlação da recuperação neural, privação auditiva e etiologia / Cochlear implant: correlation of nerve function recovery, auditory deprivation and etiology

TEMA: a Função de Recuperação do Nervo Auditivo (REC) pode ser extraída do potencial de ação das fibras neurais - ECAP (Eletrically Evoked Compound Action Potential). O ECAP pode ser influenciado pela estimulação recebida pelo nervo e pela etiologia de uma perda auditiva e, consequentemente, afetar a REC. OBJETIVO: verificar se há correlação entre REC e os fatores: etiologia, tempo de surdez e tempo de uso do AASI antes do Implante Coclear (IC). MÉTODO: estudo retrospectivo transversal. Foram coletados dados sobre etiologia, tempo de surdez, tempo de uso do Aparelho de Amplificação Sonora Individual (AASI) e REC de 50 indivíduos, 26 crianças e 24 adultos, submetidos à cirurgia de IC e usuários do dispositivo multicanal Nucleus®24. As medidas da função de recuperação do nervo auditivo foram calculadas e os pacientes foram divididos em grupos (GI: recuperação rápida, GII: recuperação intermediária e GIII: recuperação lenta) para posterior análise de relação com os demais dados coletados. RESULTADOS: a análise dos dados não mostrou correlação estatisticamente significante entre a recuperação e os aspectos pré-cirúrgicos estudados. Entretanto, foi possível observar maior concentração de ambos, crianças e adultos, nas REC intermediárias. GI não agrupou indivíduos com surdez de etiologias infecciosas, tais como a meningite, rubéola e citomegalovírus. A média de REC apresentou-se mais lenta para as etiologias infecciosas, tanto para o grupo de crianças, como para o grupo de adultos. CONCLUSÃO: não houve correlação estatisticamente significante entre função de recuperação do nervo auditivo e os fatores: etiologia, tempo de surdez e tempo de uso do AASI antes do IC.

BACKGROUND: the Auditory Nerve Recovery Function (REC) may be extracted from the Electrically Evoked Compound Action Potential (ECAP). ECAP may be influenced by the stimulation received (or the deprivation of stimulation) and by the etiology of the hearing loss, consequently it might affect the REC. AIM: to verify whether there is a correlation between the REC and each of the following factors: etiology, time of auditory deprivation and time of hearing aid use before cochlear implantation (CI). METHOD: retrospective study. Data regarding etiology, time of auditory deprivation, time of hearing aid use before cochlear implantation were collected in children and adults who received a Nucleus®24. All patients who presented neural response at surgery and whose REC was assessed intraoperatively were included in this study. Fifty patients were selected, 26 children and 24 adults. Patients were divided according to the REC classification into three groups (GI: fast recovery; GII: intermediate recovery and GIII: slow recovery) to allow correlation analysis. RESULTS: data analysis did not show any statistically significant correlation between the recovery function and the pre-implant studied characteristics. Nevertheless, it was observed that there was a greater concentration of both, children and adults, in the intermediate recovery function values. GI did not present individuals with infectious etiologies, such as meningitis, rubella and cytomegalovirus. REC average scores were slower in infectious etiologies for both children and adults. CONCLUSION: there was no statistically significant correlation between the recovery function and factors such as etiology, time of auditory deprivation and time of hearing aid use prior to CI.

Effects of Electric Stimulations Applied during Absolute Refractory Period on Cardiac Function of Rabbits with Heart Failure / 华中科技大学学报（医学）（英德文版）

The effects of electric currents applied during absolute refractory period(ARP)on the cardiac function of rabbits with heart failure due to myocardial infarction(MI),and the safety of this method were investigated.Thirty rabbits were randomly assigned equally to 3 groups: sham-operated group,LV-anterior wall cardiac contractility modulation(LV-CCM)group,and septum-CCM(S-CCM)group.A thoracotomy was performed on all the rabbits.Electric pulses were delivered during the ARP on the anterior wall of left ventricle in CCM group and in the septum in S-CCM group,respectively.The left ventricular systolic pressure(LVSP)and maximum positive left ventricular pressure change(+dp/dtmax),heart rates,ventricular tachycardia,ventricular fibrillation were observed.It was found that,as compared with the baseline,LVSP,and+dp/dtmax were significantly increased,on average,by 15.2% and 19.5% in LV-CCM group(P<0.05),and by 8.5% and 10.8% in S-CCM group(P<0.05).LVEDP was significantly decreased and-dp/dtmax increased both in LV-CCM group and S-CCM group(P<0.05).CCM had no effect on heart rate and induced no arrhythmia in short time.It is concluded that electric currents delivered during the ARP could significantly enhance the contractility of myocardium safely,suggesting that CCM stimulation is a novel potent method for contractility modulation.

Protective effect of bronchial challenge with hypertonic saline on nocturnal asthma

Inhalation of hypertonic saline (HS) causes bronchoconstriction in asthmatic subjects. Repeated inhalation of HS leads to substantially reduced bronchoconstriction, known as the refractory period. Refractoriness due to different stimuli has also been described (cross-refractoriness). Nocturnal asthma is defined as an increase in symptoms, need for medication, airway responsiveness, and/or worsening of lung function that usually occurs from 4 to 6 am. Our objective was to determine the effect of refractoriness on nocturnal asthma. The challenge test consisted of inhalations of 4.5 percent saline with increasing durations until a reduction of 20 percent in forced expiratory volume in 1 s (FEV1) (PD20HS) or total time of 15.5 min. Twelve subjects with nocturnal asthma were challenged with HS at 16:00 and 18:00 h and FEV1 was measured at 4:00 h. One to 2 weeks later, FEV1 was determined at 16:00 and 4:00 h. LogPD20HS at 18:00 h was significantly greater than logPD20HS at 16:00 h, 0.51 ± 0.50 and 0.69 ± 0.60 mg, respectively (P = 0.0033). When subjects underwent two HS challenges in the afternoon, mean (± SD) FEV1 reduction was 206 ± 414 mL or 9.81 ± 17.42 percent. On the control day (without challenge in the afternoon) FEV1 reduction was 523 ± 308 mL or 22.75 ± 15.40 percent (P = 0.021). Baseline FEV1 values did not differ significantly between the control and study days, 2.48 ± 0.62 and 2.36 ± 0.46 L, respectively. The refractory period following HS challenges reduces the nocturnal worsening of asthma. This new concept may provide beneficial applications to asthmatic patients.

Transtornos de humor refratários a tratamento / Treatment-resistant mood disorders

OBJETIVOS E MÉTODO: Os transtornos de humor estão entre os transtornos psiquiátricos mais prevalentes. Apesar de novas descobertas e avanços no estudo das bases neurobiológicas e abordagens terapêuticas no transtorno bipolar e depressão recorrente, elevadas taxas de recorrência, sintomas subsindrômicos persistentes e refratariedade terapêutica são aspectos clínicos desafiadores e precisam ser abordados. O objetivo desta revisão da literatura é o de avaliar os conceitos e critérios de resistência e refratariedade ao tratamento, e evidenciar as principais alternativas terapêuticas para transtornos do humor resistentes aos tratamentos disponíveis. RESULTADOS: Fatores genéticos, erro diagnóstico e de tratamento, não-aderência, e estressores biológicos e psicossociais podem levar à perda de mecanismos regulatórios e ao aumento na prevalência de casos de refratariedade nos transtornos de humor. Com relação aos tratamentos disponíveis, o uso de doses apropriadas, seguido por associação com um segundo ou terceiro fármaco, e após, se indicado, a troca de medicação, são etapas necessárias na busca de melhor eficácia. Entretanto, no paradigma de refratariedade terapêutica, tratamentos atuando em sistemas já conhecidos, especialmente monoaminas, freqüentemente apresentam limitada eficácia. Assim, a busca por tratamentos mais eficazes para os transtornos de humor torna-se um aspecto chave para diminuir sua morbidade. CONCLUSÃO: Estratégias focadas na regulação de vias ativadoras de neuroplasticidade, incluindo agentes antiglutamatérgicos, antagonistas de receptor glucocorticóide e neuropeptídeos, podem representar opções terapêuticas promissoras.

OBJECTIVE AND METHOD: Mood disorders are the most prevalent psychiatric disorders. Despite new insights and advances on the neurobiological basis and therapeutic approaches for bipolar disorders and recurrent depression, elevated prevalence of recurrence, persistent sub-syndromal symptoms and treatment resistance are challenging aspects and need to be urgently addressed. The objective of this literature review is to evaluate the current concepts of treatment resistance and refractoriness in mood disorders. RESULTS: Genetic factors, misdiagnosis, use of inappropriate pharmacological approaches, non-compliance and biological/psychosocial stressors account for dysfunctions in mood regulation, thus increasing the prevalence of refractory mood disorders. Regarding available treatments, the use of effective doses during an adequate period followed by augmentation with a second and/or third agent, and finally switching to other agent are steps frequently necessary to optimize efficacy. However, in the treatment-resistant paradigm, drugs mimicking standard strategies, which target preferentially the monoaminergic system, can present reduced therapeutic effects. Thus, the search for new effective treatments for mood disorders is critical to decreasing the overall morbidity secondary to treatment resistance. CONCLUSION: Emerging strategies targeting brain plasticity pathways or 'plasticity enhancers', including antiglutamatergic drugs, glucocorticoid receptor antagonists and neuropeptides, have been considered promising therapeutic options for difficult-to-treat mood disorders.

Clinical aspects of super-refractory schizophrenia: a 6-month cohort observational study

OBJECTIVE: Approximately 30 percent of treatment-resistant schizophrenic patients do not fully respond to Clozapine and such patients are termed Clozapine non-responders or super-refractory schizophrenics. The aim of this study was to characterize patients with super-refractory schizophrenia according to demographic and psychopathological variables, as compared with patients with refractory schizophrenia or non-refractory subjects. METHOD: One hundred two outpatients meeting DSM-IV criteria for schizophrenia were followed-up for 6 months. Subjects were classified into 3 groups: non-refractory (n = 25), refractory (n = 43) and super-refractory (n = 34). Psychopathology was assessed by the Positive and Negative Syndrome Scale, the Schedule for Deficit Syndrome, the Calgary Depression Scale and the Quality of Life Scale. Patients were rated at 2-month intervals. RESULTS: Higher levels of severity at the disease onset as well as higher severity of positive symptoms were found to be predictive of super-refractoriness. CONCLUSIONS: The super-refractory schizophrenia patients have psychopathological predictive factors that need studies comparing brain images, genetical features and other clinical comparisons.

OBJETIVO: Cerca de 30 por cento dos pacientes de esquizofrenia resistentes ao tratamento não respondem completamente à clozapina. Esses pacientes são denominados não respondedores à clozapina ou portadores de esquizofrenia super-refratários. O objetivo deste estudo foi caracterizar pacientes com esquizofrenia super-refratária de acordo com as variáveis demográficas e psicopatológicas, em comparação com pacientes com esquizofrenia refratária e indivíduos não refratários. MÉTODO: Cento e dois pacientes ambulatoriais que preenchiam os critérios do DSM-IV para esquizofrenia foram acompanhados durante seis meses. Os indivíduos foram classificados em três grupos: não refratários (n = 25), refratários (n = 43) e super-refratários (n = 34). A psicopatologia foi avaliada pela Escalas de Síndrome Positiva e Negativa, pelo questionário para a Síndrome Deficitária, pela Escala de Depressão de Calgary e pela Escala de Qualidade de Vida. Os pacientes foram avaliados em intervalos de dois meses. RESULTADOS: Encontrou-se que índices mais elevados de gravidade no início da doença, bem como maior gravidade dos sintomas positivos foram preditivos de super refratariedade. CONCLUSÕES: Os pacientes com esquizofrenia super-refratária apresentam fatores preditivos psicopatológicos que necessitam maior investigação em estudos de imagens cerebrais, características genéticas e outras comparações clínicas.

Changes of Monophasic Action Potential Duration and Effective Refractory Period of Three Layers Myocardium of Canine during Acute Ischemia in Vivo / 华中科技大学学报（医学）（英德文版）

The effect of acute ischemia on the electrophysiological characteristics of the three layers myocardium of canine in vivo was investigated. Twelve canines were divided into two groups randomly: acute ischemia (AI) group and sham operation (SO) group. By using the monophasic action potential (MAP) technique, MAP and effective refractory period (ERP) of thethree layers myocar dium were measured by specially designed plunge needle electrodes and the transmural dispersion of repolarization (TDR) and transmural dispersion of ERP (TDE) were analyzed. The results showed that in the AI group, MAP duration (MAPD) was shortened from 201.67±21.42 ms to 169.50±13.81 ms (P＜0.05), but ERP prolonged to varying degrees and TDE increased during ischemia.In the SO group, MAPD and ERP did not change almost. Among of the three layers myocardium of canine, MAPD was coincident in two groups. It was concluded that during acute ischemia, MAPD was shortened sharply, but there was no significant difference among of the three layers myocardium. The prolonged ERP was concomitant with increased TDE during acute ischemia, which may play an important role in the occurrence of arrhythmias induced by acute ischemia. These findings may have important implications in arrhythmogenesis.

Effects of A_3 site from Angelica naphtha on myocardial physiological properties and action potentials / 中国药理学通报

AIM To study the effects of A 3 site (components), extracted from Angelica naphtha (total oil),on physiological properties of isolated rat atrium and action potential of isolated guinea pig ventricular papillary muscles. METHODS Spontaneous beats, contractile force and functional refractory period(FRP) of isolated atrial muscle were recorded according to the regular methods. Standard microelectrode intracellular recording technique was used to record action potential(AP) of ventricular papillary muscles. RESULTS A 3 site(10～160 mg?L -1 ) dramatically inhibited spontaneous beats of isolated rat right atrium and made beats stop with 160 mg?L -1 . A 3 site concentration dependently reduced contractile force of isolated rat left atrium induced by electrostimulating, with the IC 50 value of 52 3 mg?L -1 . A 3 site(40～100 mg?L -1 ) obviously prolonged FRP. The FRP was prolonged from 106 ms (as control) to 130 ms at final concentration of 100 mg?L -1 . A 3 site decreased action potential amplitude (APA), shortened 20%APD(APD 20 ) and 90%APD(APD 90 ), but had no significant effect on RP of AP. CONCLUSION The mechanism of these effects of A 3 site on myocardial physiological properties and action potential was probably associated with blocking the influx of Ca 2+ and Na +, promoting K + outflux.

Effects of electric stimulation applied during absolute refractory period on contraction and relaxation of ventricular myocytes in normal and failure guinea-pigs / 西安交通大学学报(医学版)

Objective To investigate the effect of electric stimulation applied during absolute refractory period on contraction and relaxation and Ca 2+ transient of ventricular myocytes from normal guinea-pigs. Methods The ventricular myocytes of guinea-pigs were obtained by enzyme digesting, and the extent of the contraction and relaxation and Ca 2+ transient were recorded through the motion edge detection system. The Ca 2+ transient was reflected by fluorescence ratio (360/380) ( F 360/F 380). Results The ventricular myocytes from the normal guinea-pigs: ①The contraction extent of guinea-pig ventricular myocytes increased by (16.55?5.49)%. The peak velocity of shorting (contraction) and the peak velocity of relengthening (relaxation) increased by (17.43?7.08)% and (19.74?9.08)%, respectively(n=10); ②The extent of F 360/F 380 increased (25.79?6.88)%. The peak velocity of F 360/F 380 increased by (29.47?9.25)% and (22.52?7.81)% during shortening and relengthening, respectively(n=10). The ventricular myocytes from failure guinea-pigs: ①The contraction extent of guinea-pig ventricular myocytes increased by (15.53?5.31)%. The peak velocity of shortening (contraction) and the peak velocity of relengthening (relaxation) increased by (10.60?3.02)% and (23.32?8.26)%, respectively(n=6); ②The extent of F 360/F 380 increased (16.82?7.03)%. The peak velocity of F 360/F 380 increased by (16.27?5.91)% and (10.32?2.46)% during shorenting and relengthening, respectively(n=6). Conclusion Appropriate electric stimulation applied during absolute refractory period might strengthen the contracting and relaxing function of normal and failing ventricular myocytes in guinea-pigs.

Effects of xanthotoxol on physiological characteristics of isolated guinea pig atrium / 中国临床药理学与治疗学

AIM: To study the effects of xanthotoxol (XT) on physiological characteristics and its mechanism in isolated guinea pig atria. METHODS: It was determined by the contractile amplitude,excitability and the spontaneous beats in the right atria,respectively. RESULTS: In the experiment of contractile amplitude,after 15 min of administration of XT 20, 40 and 80 ?mol?L -1 ,the contractile force of left atria was 0.85 , 0.68 ,and 0.48 g,respectively (P

Effects of TFC on the right ventricle papillary muscles of guinea pig / 中国药理学通报

AIM: To study the mechanism of effects about total flavones of choeropondias axillaris (TFC) to heart. METHODS: The effects of TFC on contractility were investigated through acting on the guinea pig right ventricle papillary muscles. RESULTS: TFC decreased both the contractility and contraction rate of papillary muscles. The quantity-effect curve of CaCl2 was shifted to right after giving TFC. TFC 30.4 μmol·L-1 prolonged remarkably the functional refractory period (FRP) of guinea pig right ventricle papillary muscles, but exerted no effect on excitability. CONCLUSION: TFC can inhibit the Ca2+ influx into cell in a concentration-dependent manner.