Objectives To evaluate the changes in atrial effective refractory period （AERP） proprieties and in ionic currents in PVs myocytes from dogs subjected to rapid atrial pacing in PVs and right atrial appendage （RAA） ...Objectives To evaluate the changes in atrial effective refractory period （AERP） proprieties and in ionic currents in PVs myocytes from dogs subjected to rapid atrial pacing in PVs and right atrial appendage （RAA） and to relate these changes to the ability to induce AF. Methods Twelve mongrel dogs in normal sinus rhythm were paced from the superior left PVs or RAA at 500 bpm for 4 hours. Electrophysiologic studies conducted to determine changes in AERP, dispersion and rhythm. Ionic currents were studies with the patch clamp technique in single PVs myocytes in sham operated dogs and compared with those from PVs pacing and RAA pacing groups. Results The presence of rapid atrial pacing was associated with a marked shortening in AERP in both PVs and RAA pacing group with a marked increase of AERP dispersion in PVs pacing. Both L-type calcium current （Ica L ） and the transient outward current （ Ito ） were reduced in both groups with an increased significance in PVs pacing group. The density of ICa-L was decreased significantly from （ - 6. 03 ± 0. 63 ） pA./pF in the control group to （ -3.21 ±0. 34） pA/pF in PVs pacing group and （ - 4. 75 ± 0. 41 ） pA./pF in RAA pacing group （ n = 6, P 〈 0. 05 ） while the density of Ito was decreased significantly from （8.45 ± 0. 71 ） pA./pF in the control group to （ 5.21 ± 0. 763 ） pA./pF in PVs pacing group and （6. 84 ±0. 69 ） pA./pF in RAA pacing group （ n = 6, P 〈 0. 05 ）. Conclusions Our findings provide likely ionic mechanisms of shortened repolarization in induced atrial tachycardia with a decrease in Ica L and /tocurrent densities which is the likely mechanism for a decrease in Action potential duration （APD） rate adaptation in the canine rapid pacing model more pronounced in PVs pacing group underlying the crucial role of PVs in initiating AF.展开更多
目的探讨经快速双上肺静脉起搏方法制作犬心房颤动动物模型的可行性。方法10只健康比格犬经开胸途径植入十极导管电极，快速（1200次／min）起搏双上肺静脉6h。观察房颤诱发情况，对起搏前后双上肺静脉及左心耳电生理检查结果进行比较...目的探讨经快速双上肺静脉起搏方法制作犬心房颤动动物模型的可行性。方法10只健康比格犬经开胸途径植入十极导管电极，快速（1200次／min）起搏双上肺静脉6h。观察房颤诱发情况，对起搏前后双上肺静脉及左心耳电生理检查结果进行比较。结果8只犬完成实验，房颤诱导成功率80％。高频率刺激诱发的房颤模型能使双上肺静脉区及左心耳部位ERP先降低后升高（145±15．1 vs 130±16．3vs136±11．4，P=0．004、P＝0．494），存在统计学显著差异。诱发房颤5h后，总的房颤诱发窗口（∑WOV）较基线略有升高，但无明显统计学差异（26．7士65．3vs 20±52．9，P〉0．05）。而在乙酰胆碱诱发房颤（第0h、1h、3h、6h）时，可见房颤的诱发时间呈现先上升后下降的过程，而这种趋势与ERP的变化趋势存在相关性。结论经快速双上肺起搏方法制作心房颤动动物模型，可用于房颤发病机理、电生理重构、心肌重构、分子生物学改变等临床研究，也可用于心动过速性心肌病及部分心力衰竭的研究。展开更多
文摘Objectives To evaluate the changes in atrial effective refractory period （AERP） proprieties and in ionic currents in PVs myocytes from dogs subjected to rapid atrial pacing in PVs and right atrial appendage （RAA） and to relate these changes to the ability to induce AF. Methods Twelve mongrel dogs in normal sinus rhythm were paced from the superior left PVs or RAA at 500 bpm for 4 hours. Electrophysiologic studies conducted to determine changes in AERP, dispersion and rhythm. Ionic currents were studies with the patch clamp technique in single PVs myocytes in sham operated dogs and compared with those from PVs pacing and RAA pacing groups. Results The presence of rapid atrial pacing was associated with a marked shortening in AERP in both PVs and RAA pacing group with a marked increase of AERP dispersion in PVs pacing. Both L-type calcium current （Ica L ） and the transient outward current （ Ito ） were reduced in both groups with an increased significance in PVs pacing group. The density of ICa-L was decreased significantly from （ - 6. 03 ± 0. 63 ） pA./pF in the control group to （ -3.21 ±0. 34） pA/pF in PVs pacing group and （ - 4. 75 ± 0. 41 ） pA./pF in RAA pacing group （ n = 6, P 〈 0. 05 ） while the density of Ito was decreased significantly from （8.45 ± 0. 71 ） pA./pF in the control group to （ 5.21 ± 0. 763 ） pA./pF in PVs pacing group and （6. 84 ±0. 69 ） pA./pF in RAA pacing group （ n = 6, P 〈 0. 05 ）. Conclusions Our findings provide likely ionic mechanisms of shortened repolarization in induced atrial tachycardia with a decrease in Ica L and /tocurrent densities which is the likely mechanism for a decrease in Action potential duration （APD） rate adaptation in the canine rapid pacing model more pronounced in PVs pacing group underlying the crucial role of PVs in initiating AF.
文摘目的探讨经快速双上肺静脉起搏方法制作犬心房颤动动物模型的可行性。方法10只健康比格犬经开胸途径植入十极导管电极，快速（1200次／min）起搏双上肺静脉6h。观察房颤诱发情况，对起搏前后双上肺静脉及左心耳电生理检查结果进行比较。结果8只犬完成实验，房颤诱导成功率80％。高频率刺激诱发的房颤模型能使双上肺静脉区及左心耳部位ERP先降低后升高（145±15．1 vs 130±16．3vs136±11．4，P=0．004、P＝0．494），存在统计学显著差异。诱发房颤5h后，总的房颤诱发窗口（∑WOV）较基线略有升高，但无明显统计学差异（26．7士65．3vs 20±52．9，P〉0．05）。而在乙酰胆碱诱发房颤（第0h、1h、3h、6h）时，可见房颤的诱发时间呈现先上升后下降的过程，而这种趋势与ERP的变化趋势存在相关性。结论经快速双上肺起搏方法制作心房颤动动物模型，可用于房颤发病机理、电生理重构、心肌重构、分子生物学改变等临床研究，也可用于心动过速性心肌病及部分心力衰竭的研究。
