心脏脂肪垫在肺静脉灶性放电引发心房颤动中的作用

探讨心脏脂肪垫在肺静脉灶性放电与心房颤动 (简称房颤 )中的作用。 14条狗麻醉后经右侧开胸暴露右侧肺静脉。将 8极电极标测导管缝在右上肺静脉用于起搏。另放一 8极电极导管固定在临近右肺静脉和左房交接处脂肪垫。术中监测ECG的II和aVR导联、血压和体温。以 0 .1ms刺激间期 ,2 0Hz刺激频率的直方波刺激脂肪垫的迷走神经丛 30～ 5 0s,随着电压从 1～ 4 .5V ,心率逐渐减少 (P <0 .0 5 ) ,同时出现房性早搏、房性心动过速和房颤。在刺激迷走神经丛的同时 ,以 2 0 0～ 80 0次 /分的频率刺激肺静脉 (对照组没有迷走神经丛刺激 )均能诱发房颤。在迷走神经丛刺激下 ,以S1S1330ms,S1S2 稍长于肺静脉不应期的配对间期刺激肺静脉诱发房颤。与对照组比较 ,在迷走神经刺激下 ,肺静脉刺激诱发房颤的房性早搏数 ,随着刺激电压从 0 .6到 3V的增加 ,从 7个减少到 2个 (P <0 .0 5 )。 7条狗局部去神经后 ,6条狗在同样肺静脉刺激诱发房颤的电压条件下不能诱发房颤 ,其中有 3条在电压大于 9V时诱发房颤。结论 :在临近右肺静脉和左房交接处脂肪垫刺激可以将肺静脉灶性放电转变成房颤。因此 ,临床上自发的迷走神经丛的张力增高是肺静脉灶性放电转变成房颤的基础。

Effects of Fad Pad Between Right Pulmonary Vein and Left Atrial on Converting Focal Pulmonary Vein Firing into Atrial Fibrillation

In 14 dogs, the right superior pulmonary vein(RSPV) was exposed via a right thoractomy; an octapolar electrode catheter was sutured against the RPSV for pacing site.Another octapolar electrode cathete′s tip closed to the fad pad containing a ganglionated plexus(GP) at the junction of right pulmonary vein-left atrial.ECG leadsⅡand aVR,blood pressure and temperature were continuously monitored .The GP be stimulated with 0.1ms duration and 20 Hz frequency for 30-50s.The GP stimulation caused a progressive reduction in heart rate ( P <0.05)and the atrial premature,atrial tachycardia and atrial fibrillation(AF) compared with the control group;Pacing RSPV at rates between 200-800 bpm while stimulating the GP within the same voltage range induced AF,Focal firing of the RSPVwas also stimulated by pacing RSPV at S 1S 1 330 ms,8:1 and S 1S 2 at coupling interval just longer than RSPV refractoriness .Compared with control without GP stimulating ,the fewest number of atrial depolarization required to induce AF was from 7±4 bpm 0.6 V to 2±1 bpm 3 V.In 7dogs anesthetized with lidocaine(2%4 ml) at GP,6 of 7dogs,AF could not be induced,and 3 of 7 dogs,atria fibrillation be induced with voltage more than 9V.Conclusion:The effects of stimulation at GP could covert pulmonary vein focal firing into AF,thus increased tone of autonomic nervous at Gp clinically could be the substrate for transducing focal pulmonary vein firing into paroxysmal AF.