An ishemic ventricular tachyarrhythmias canine model was established in open-chest dogs subjected to programmed electrical stimulation (PES)for 5-8 days after acute myocardial infarction. The electrophysiologic effect...An ishemic ventricular tachyarrhythmias canine model was established in open-chest dogs subjected to programmed electrical stimulation (PES)for 5-8 days after acute myocardial infarction. The electrophysiologic effects of neferine (Nef) and procainamide (PA) were observed in this model. With routine methods of PES,ventricular tachycardia (VT)and ventricular fibrillation (VF) could be reproducibly initiated. Both drugs lengthened the QTc interval (P【0.01) and effective refractory period(ERP)of normal and ischemic ventricular myocardia (NERP and IERP) respectively (P【0.01), decreased the dispersion of ERP in ischemic myocardium and the dispersion of ERP in left ventricle (P【0.01), and increased the diastolic excitability threshold of normal and ischemic ventricular myocardia (P【0.01). The two compounds prevented the PES-induced VT or VF (Nef group P【0.01, PA group P【0.05) and ischemia-induced VF (P【0.05). The results indicated that neferine and procainamide may be effective in preventing the onset of reentrant ventricular tachyarrhythmias after myocardial ischemic damage in dogs.展开更多
Objective To establish a canine model of electrophysiologic - electropharmacology as assessed by programmed electrical stimulation (PES),and to observe the electrophysiologic effects of Procainamide(PA) on normal and...Objective To establish a canine model of electrophysiologic - electropharmacology as assessed by programmed electrical stimulation (PES),and to observe the electrophysiologic effects of Procainamide(PA) on normal and ischemic myocardium in case of ischemic ventricular tachyarrhythmia in this model. Methods A ishemic ventricular tachyarrhythmias canine model was established in open-chest dogs subjected to programmed electrical stimulation(PES)for 5-8 days after acute myocardial infarction. The electrophysiologic effects of procainamide were observed in this model. With routine methods of PES,ventricular tachycardia(VT) and ventricular fibrillation (VF) could be reproducibly initiated. Results Procainamide distinctly lengthened the QTc interval (P【0.01) and effective refractory period(ERP) of normal and ischemic ventricular myocardium(NERP and IERP) respectively (P【0.01), decreased the dispersion of ERP in ischemic myocardium and the dispersion of ERP in left ventricle (P【0.01), and increased the diastolic excitability threshold of normal and ischemic ventricular myocardium remarkably (P【0.01). Procainamide effectively prevented the PES-induced VT or VF (P【0.05) and ischemia-induced VF (P【0.05). Conclusion The results indicated that PES-induced VT/VF were highly reproducible and reliable, this canine model is a worthy and reliable one, procainamide may be effective in preventing the onset of VT and VF after myocardial ischemic damage, and deserves further attention as an antifibrillatory agent.展开更多
A canine model of ischemic ventricular tachyarrhythmias was established in open-chest dogs subjected to programmed electrical stimulation (PES) for 5￣8 days after acute myocardial infarction. The electrophysiologic e...A canine model of ischemic ventricular tachyarrhythmias was established in open-chest dogs subjected to programmed electrical stimulation (PES) for 5￣8 days after acute myocardial infarction. The electrophysiologic effects of sophoridine (Sop) and procainamide (PA) were observed in this canine model. With routine methods of PES, ventricular tachycardia (VT) and ventricular fibrilation (VF) could be reproducibly initiated in this model. Both drugs distinctly lengthened the QTc interval ( P <0.01) and the effective refractory period (ERP) in normal and ischemic ventricular myocardium ( P <0.01), decreased the dispersion of ERP in ischemic myocardium and the dispersion of ERP in left ventricle (P <0.05), and increased the diastolic excitability threshold of normal and ischemic ventricular myocardium remarkably ( P <0.01). Both drugs effectively prevented the PES-induced VT or VF and ischemia-induced VF ( P <0.05). The results indicated that this canine model is a good and reliable one, sophoridine and procainamide may be effective in preventing the onset of reentrant ventricular tachyarrhythmias after myocardial ischemic damage.展开更多
Using patch clamp whole cell recording techiques, we examined the effects ofIQ_23, a benzyl-isoquinoline derivative with antiarrhythmic activities, on the action potential (AP) andpotassium currents in single guinea p...Using patch clamp whole cell recording techiques, we examined the effects ofIQ_23, a benzyl-isoquinoline derivative with antiarrhythmic activities, on the action potential (AP) andpotassium currents in single guinea pig ventricular myocytes. The results showed that IQ_23 at 10, 30and 100 μmol ·L_-1 slowed the repolarization in AP dose-dependently. The APD_90 were prolonged by15%, 28% and 31% respectively. This effect did not depend on the extracellular Ca^2+. In voltageclamp mode, IQ_23 effectively blocked both the components of the delayed rectifier potassium current(I_k), i.e., I_ks and I_kr. At concentrations of 30 and 100 μmol· L^-1, IQ_23 suppressed I_ks by 21% and 26%and suppressed I_kr by 67% and 86% respectively. But even at 100 μmol·L^-1, IQ_23 had little effect onthe inward rectifier potassium current (I_k1). It is concluded: 1. IQ_23 can dose-dependently prolongAPD in the ventriculas myocytes of guinea pig, the effect does not depend on the extracellular Ca^2+; 2.IQ_23 blocks both I_ks and Ikr in the ventricular myocytes without obvious specificities between them.展开更多
Using patch clamp whole cell recording techiques, we examined the effects ofIQ<sub>2</sub>3, a benzyl-isoquinoline derivative with antiarrhythmic activities, on the action potential （AP） andpotassium cur...Using patch clamp whole cell recording techiques, we examined the effects ofIQ<sub>2</sub>3, a benzyl-isoquinoline derivative with antiarrhythmic activities, on the action potential （AP） andpotassium currents in single guinea pig ventricular myocytes. The results showed that IQ<sub>2</sub>3 at 10, 30and 100 μmol ·L<sub>-</sub>1 slowed the repolarization in AP dose-dependently. The APD<sub>9</sub>0 were prolonged by15%, 28% and 31% respectively. This effect did not depend on the extracellular Ca<sup>2</sup>+. In voltageclamp mode, IQ<sub>2</sub>3 effectively blocked both the components of the delayed rectifier potassium current（I<sub>k</sub>）, i.e., I<sub>k</sub>s and I<sub>k</sub>r. At concentrations of 30 and 100 μmol· L<sup>-</sup>1, IQ<sub>2</sub>3 suppressed I<sub>k</sub>s by 21% and 26%and suppressed I<sub>k</sub>r by 67% and 86% respectively. But even at 100 μmol·L<sup>-</sup>1, IQ<sub>2</sub>3 had little effect onthe inward rectifier potassium current （I<sub>k</sub>1）. It is concluded: 1. IQ<sub>2</sub>3 can dose-dependently prolongAPD in the ventriculas myocytes of guinea pig, the effect does not depend on the extracellular Ca<sup>2</sup>+; 2.IQ<sub>2</sub>3 blocks both I<sub>k</sub>s and Ikr in the ventricular myocytes without obvious specificities between them.展开更多
Guan-fu base A(GFA),a new antiarrhythmic alkaloid with a structure of C_(20)-diterpenoid could react rapidly and quantitatively with trifluoroacetic anhydride(TFAA) to produce GFA—TFAA of which the structure was iden...Guan-fu base A(GFA),a new antiarrhythmic alkaloid with a structure of C_(20)-diterpenoid could react rapidly and quantitatively with trifluoroacetic anhydride(TFAA) to produce GFA—TFAA of which the structure was identified by GC—MSD.There was a wide linear range of the GC-ECD method from 10 to 20000ng/ml(r=0.9984).The average recovery of GFA from the spiked plasma was 97.52%.The coefficients of variation of within-day and between-day were less than 7% and 9%,respectively.The method was used in the preclinical experiment of pharmacology of GFA and the results showed that GFA con- centrations in rabbits' plasma within 6 hours after the administration ranged from 0.338± 0.014 to 13.459±5.393μg/ml for dosage 10mg/kg,from 0.133±0.038 to 2.546±0.480 μg/ml for dosage 2mg/kg and from 45.25±10.34 to 535.86±24.36ng/ml for dosage 0.4 mg/kg.展开更多
Atrial fibrillation （AF） is the most common arrhythmia diagnosed in clinical practice. The consequences of AF have been clearly estab- lished in multiple large observational cohort studies and include increased stro...Atrial fibrillation （AF） is the most common arrhythmia diagnosed in clinical practice. The consequences of AF have been clearly estab- lished in multiple large observational cohort studies and include increased stroke and systemic embolism rates if no oral anticoagulation is prescribed, with increased morbidity and mortality. With the worldwide aging of the population characterized by a large influx of ＂baby boomers＂ with or without risk factors for developing AF, an epidemic is forecasted within the next 10 to 20 years. Although not all studies support this evidence, it is clear that AF is on the rise and a significant amount of health resources are invested in detecting and managing AF This review focuses on the worldwide burden of AF and reviews global health strategies focused on improving detection, prevention and risk stratification of AF, recently recommended by the World Heart Federation.展开更多
The previous experimental studies have demonstrated that addition of Huang Qi ([symbol: see text] Radix Astragali) to the formulated recipe Sheng Mai Yin ([symbol: see text] Decoction for Pulse-activation) exerts the ...The previous experimental studies have demonstrated that addition of Huang Qi ([symbol: see text] Radix Astragali) to the formulated recipe Sheng Mai Yin ([symbol: see text] Decoction for Pulse-activation) exerts the effects of strengthening the myodynamia, increasing the coronary flow, improving myocardial metabolism, and resisting the arrhythmia. The active component of Huang Lian ([symbol: see text] Rhizoma Coptidis) can prolong the myocardial action potential and antagonize the chloroform-, aconitine-, barium chloride-, epinephrine- or coronary ligation-induced arrhythmia by blocking the calcium channel. Ku Shen ([symbol: see text] Radix Sophorae Flavescentis) contains matrine and flavones, which act as quinidine to decrease the excitability of the myocardium, prolong the refractory period, and inhibit the ectopic cardiac rhythm. And Dan Shen ([symbol: see text] Radix Salviae Miltiorrhizae) has the action of improving the ischemic state of the myocardium by dilating the coronary vessels. In conclusion, the definite therapeutic effects of Huang Lian Sheng Mai Yin in treating ventricular, atrial and nodal arrhythmia suggests that the prescription is rational and accords with the therapeutic principle of TCM. Except discomfort in the gastric cavity and poor appetite experienced by some patients, there is no toxic or adverse reaction.展开更多
Atrial fibrosis is common in atrial fibrillation （AF）. Experimental studies have provided convincing evidence that fibrotic transformation of atrial myocardium results in deterioration of atrial conduction, increasi...Atrial fibrosis is common in atrial fibrillation （AF）. Experimental studies have provided convincing evidence that fibrotic transformation of atrial myocardium results in deterioration of atrial conduction, increasing anisotropy of impulse propagation and building of boundaries that promote re-entry in the atrial walls that maybe directly relevant for the mechanisms responsible for maintaining AF. Whether or not fibrosis is a result of structural remodelling caused by persistent AF or a manifestation of occult myocardial process that leads to development of arrhythmia is less clear. Human data indicate the presence of association between persistency of AF and the extent of structural changes in atrial myocardium. The role atrial fibrosis plays in the mechanisms of AF, however, may differ between patients with structurally normal hearts, such as lone AF, and those with advanced cardiovascular comorbidities.展开更多
This review discusses atrial fibrillation according to the guidelines of Brazilian Society of Cardiac Arrhythmias and the Brazilian Cardiogeriatrics Guidelines. We stress the thromboembolic burden of atrial fibrillati...This review discusses atrial fibrillation according to the guidelines of Brazilian Society of Cardiac Arrhythmias and the Brazilian Cardiogeriatrics Guidelines. We stress the thromboembolic burden of atrial fibrillation and discuss how to prevent it as well as the best way to conduct cases of atrial fibrillatios in the elderly, reverting the arrhythmia to sinus rhythm, or the option of heart rate control. The new methods to treat atrial fibrillation, such as radiofrequency ablation, new oral direct thrombin inhibitors and Xa factor inhibitors, as well as new antiarrhythmic drugs, are depicted.展开更多
文摘An ishemic ventricular tachyarrhythmias canine model was established in open-chest dogs subjected to programmed electrical stimulation (PES)for 5-8 days after acute myocardial infarction. The electrophysiologic effects of neferine (Nef) and procainamide (PA) were observed in this model. With routine methods of PES,ventricular tachycardia (VT)and ventricular fibrillation (VF) could be reproducibly initiated. Both drugs lengthened the QTc interval (P【0.01) and effective refractory period(ERP)of normal and ischemic ventricular myocardia (NERP and IERP) respectively (P【0.01), decreased the dispersion of ERP in ischemic myocardium and the dispersion of ERP in left ventricle (P【0.01), and increased the diastolic excitability threshold of normal and ischemic ventricular myocardia (P【0.01). The two compounds prevented the PES-induced VT or VF (Nef group P【0.01, PA group P【0.05) and ischemia-induced VF (P【0.05). The results indicated that neferine and procainamide may be effective in preventing the onset of reentrant ventricular tachyarrhythmias after myocardial ischemic damage in dogs.
文摘Objective To establish a canine model of electrophysiologic - electropharmacology as assessed by programmed electrical stimulation (PES),and to observe the electrophysiologic effects of Procainamide(PA) on normal and ischemic myocardium in case of ischemic ventricular tachyarrhythmia in this model. Methods A ishemic ventricular tachyarrhythmias canine model was established in open-chest dogs subjected to programmed electrical stimulation(PES)for 5-8 days after acute myocardial infarction. The electrophysiologic effects of procainamide were observed in this model. With routine methods of PES,ventricular tachycardia(VT) and ventricular fibrillation (VF) could be reproducibly initiated. Results Procainamide distinctly lengthened the QTc interval (P【0.01) and effective refractory period(ERP) of normal and ischemic ventricular myocardium(NERP and IERP) respectively (P【0.01), decreased the dispersion of ERP in ischemic myocardium and the dispersion of ERP in left ventricle (P【0.01), and increased the diastolic excitability threshold of normal and ischemic ventricular myocardium remarkably (P【0.01). Procainamide effectively prevented the PES-induced VT or VF (P【0.05) and ischemia-induced VF (P【0.05). Conclusion The results indicated that PES-induced VT/VF were highly reproducible and reliable, this canine model is a worthy and reliable one, procainamide may be effective in preventing the onset of VT and VF after myocardial ischemic damage, and deserves further attention as an antifibrillatory agent.
文摘A canine model of ischemic ventricular tachyarrhythmias was established in open-chest dogs subjected to programmed electrical stimulation (PES) for 5￣8 days after acute myocardial infarction. The electrophysiologic effects of sophoridine (Sop) and procainamide (PA) were observed in this canine model. With routine methods of PES, ventricular tachycardia (VT) and ventricular fibrilation (VF) could be reproducibly initiated in this model. Both drugs distinctly lengthened the QTc interval ( P <0.01) and the effective refractory period (ERP) in normal and ischemic ventricular myocardium ( P <0.01), decreased the dispersion of ERP in ischemic myocardium and the dispersion of ERP in left ventricle (P <0.05), and increased the diastolic excitability threshold of normal and ischemic ventricular myocardium remarkably ( P <0.01). Both drugs effectively prevented the PES-induced VT or VF and ischemia-induced VF ( P <0.05). The results indicated that this canine model is a good and reliable one, sophoridine and procainamide may be effective in preventing the onset of reentrant ventricular tachyarrhythmias after myocardial ischemic damage.
文摘Using patch clamp whole cell recording techiques, we examined the effects ofIQ_23, a benzyl-isoquinoline derivative with antiarrhythmic activities, on the action potential (AP) andpotassium currents in single guinea pig ventricular myocytes. The results showed that IQ_23 at 10, 30and 100 μmol ·L_-1 slowed the repolarization in AP dose-dependently. The APD_90 were prolonged by15%, 28% and 31% respectively. This effect did not depend on the extracellular Ca^2+. In voltageclamp mode, IQ_23 effectively blocked both the components of the delayed rectifier potassium current(I_k), i.e., I_ks and I_kr. At concentrations of 30 and 100 μmol· L^-1, IQ_23 suppressed I_ks by 21% and 26%and suppressed I_kr by 67% and 86% respectively. But even at 100 μmol·L^-1, IQ_23 had little effect onthe inward rectifier potassium current (I_k1). It is concluded: 1. IQ_23 can dose-dependently prolongAPD in the ventriculas myocytes of guinea pig, the effect does not depend on the extracellular Ca^2+; 2.IQ_23 blocks both I_ks and Ikr in the ventricular myocytes without obvious specificities between them.
文摘Using patch clamp whole cell recording techiques, we examined the effects ofIQ<sub>2</sub>3, a benzyl-isoquinoline derivative with antiarrhythmic activities, on the action potential （AP） andpotassium currents in single guinea pig ventricular myocytes. The results showed that IQ<sub>2</sub>3 at 10, 30and 100 μmol ·L<sub>-</sub>1 slowed the repolarization in AP dose-dependently. The APD<sub>9</sub>0 were prolonged by15%, 28% and 31% respectively. This effect did not depend on the extracellular Ca<sup>2</sup>+. In voltageclamp mode, IQ<sub>2</sub>3 effectively blocked both the components of the delayed rectifier potassium current（I<sub>k</sub>）, i.e., I<sub>k</sub>s and I<sub>k</sub>r. At concentrations of 30 and 100 μmol· L<sup>-</sup>1, IQ<sub>2</sub>3 suppressed I<sub>k</sub>s by 21% and 26%and suppressed I<sub>k</sub>r by 67% and 86% respectively. But even at 100 μmol·L<sup>-</sup>1, IQ<sub>2</sub>3 had little effect onthe inward rectifier potassium current （I<sub>k</sub>1）. It is concluded: 1. IQ<sub>2</sub>3 can dose-dependently prolongAPD in the ventriculas myocytes of guinea pig, the effect does not depend on the extracellular Ca<sup>2</sup>+; 2.IQ<sub>2</sub>3 blocks both I<sub>k</sub>s and Ikr in the ventricular myocytes without obvious specificities between them.
文摘Guan-fu base A(GFA),a new antiarrhythmic alkaloid with a structure of C_(20)-diterpenoid could react rapidly and quantitatively with trifluoroacetic anhydride(TFAA) to produce GFA—TFAA of which the structure was identified by GC—MSD.There was a wide linear range of the GC-ECD method from 10 to 20000ng/ml(r=0.9984).The average recovery of GFA from the spiked plasma was 97.52%.The coefficients of variation of within-day and between-day were less than 7% and 9%,respectively.The method was used in the preclinical experiment of pharmacology of GFA and the results showed that GFA con- centrations in rabbits' plasma within 6 hours after the administration ranged from 0.338± 0.014 to 13.459±5.393μg/ml for dosage 10mg/kg,from 0.133±0.038 to 2.546±0.480 μg/ml for dosage 2mg/kg and from 45.25±10.34 to 535.86±24.36ng/ml for dosage 0.4 mg/kg.
文摘Atrial fibrillation （AF） is the most common arrhythmia diagnosed in clinical practice. The consequences of AF have been clearly estab- lished in multiple large observational cohort studies and include increased stroke and systemic embolism rates if no oral anticoagulation is prescribed, with increased morbidity and mortality. With the worldwide aging of the population characterized by a large influx of ＂baby boomers＂ with or without risk factors for developing AF, an epidemic is forecasted within the next 10 to 20 years. Although not all studies support this evidence, it is clear that AF is on the rise and a significant amount of health resources are invested in detecting and managing AF This review focuses on the worldwide burden of AF and reviews global health strategies focused on improving detection, prevention and risk stratification of AF, recently recommended by the World Heart Federation.
文摘The previous experimental studies have demonstrated that addition of Huang Qi ([symbol: see text] Radix Astragali) to the formulated recipe Sheng Mai Yin ([symbol: see text] Decoction for Pulse-activation) exerts the effects of strengthening the myodynamia, increasing the coronary flow, improving myocardial metabolism, and resisting the arrhythmia. The active component of Huang Lian ([symbol: see text] Rhizoma Coptidis) can prolong the myocardial action potential and antagonize the chloroform-, aconitine-, barium chloride-, epinephrine- or coronary ligation-induced arrhythmia by blocking the calcium channel. Ku Shen ([symbol: see text] Radix Sophorae Flavescentis) contains matrine and flavones, which act as quinidine to decrease the excitability of the myocardium, prolong the refractory period, and inhibit the ectopic cardiac rhythm. And Dan Shen ([symbol: see text] Radix Salviae Miltiorrhizae) has the action of improving the ischemic state of the myocardium by dilating the coronary vessels. In conclusion, the definite therapeutic effects of Huang Lian Sheng Mai Yin in treating ventricular, atrial and nodal arrhythmia suggests that the prescription is rational and accords with the therapeutic principle of TCM. Except discomfort in the gastric cavity and poor appetite experienced by some patients, there is no toxic or adverse reaction.
文摘Atrial fibrosis is common in atrial fibrillation （AF）. Experimental studies have provided convincing evidence that fibrotic transformation of atrial myocardium results in deterioration of atrial conduction, increasing anisotropy of impulse propagation and building of boundaries that promote re-entry in the atrial walls that maybe directly relevant for the mechanisms responsible for maintaining AF. Whether or not fibrosis is a result of structural remodelling caused by persistent AF or a manifestation of occult myocardial process that leads to development of arrhythmia is less clear. Human data indicate the presence of association between persistency of AF and the extent of structural changes in atrial myocardium. The role atrial fibrosis plays in the mechanisms of AF, however, may differ between patients with structurally normal hearts, such as lone AF, and those with advanced cardiovascular comorbidities.
文摘This review discusses atrial fibrillation according to the guidelines of Brazilian Society of Cardiac Arrhythmias and the Brazilian Cardiogeriatrics Guidelines. We stress the thromboembolic burden of atrial fibrillation and discuss how to prevent it as well as the best way to conduct cases of atrial fibrillatios in the elderly, reverting the arrhythmia to sinus rhythm, or the option of heart rate control. The new methods to treat atrial fibrillation, such as radiofrequency ablation, new oral direct thrombin inhibitors and Xa factor inhibitors, as well as new antiarrhythmic drugs, are depicted.
