Kruse I B, Rydén L, Ydse B
Pacing Clin Electrophysiol. 1980 Jul;3(4):395-405. doi: 10.1111/j.1540-8159.1980.tb05248.x.
The Medtronic 6961 lead has been used in 14 patients for transvenous atrial sensing and/or pacing. This lead is furnished with small tines of silicone rubber at the distal end. The conductor coil material is space wound for flexibility. Thus, the lead lacks intrinsic elasticity and can be fastened within the right atrial appendage without a preformed J-shape. The clinical experiences with the lead are encouraging. The lead is easier to introduce and position in the right atrial appendage than the previously used tined J-shaped leads (Medtronic 6991). The small size of the new lead makes the choice of vein less critical and a normally-sized external jugular or cephalic vein permits the use of the same vessel for a second ventricular lead. By means of a lead extension wire, consecutive determinations of the P-wave amplitude, stimulation threshold of the right atrium, electrode resistance, and P/QRS-ratio were made for four weeks following electrode insertion. The mean P-wave amplitude at insertion was 4.9 +/- 1.5 mV (mean +/- SD). There was a significant decrease to a lowest mean level of 309 +/- 1.1 mV after one week. From that time there were only small variations. In the supine position and with normal breathing there was a spontaneous variation of the P-wave amplitude of +/- 12%. The P-wave amplitude was influenced by body position and maximal breathing movements to a minor extent. The threshold of stimulation was 0.9 +/- 0.4 V after one week. Later there was a small decrease in the threshold which, however, still remained significantly higher than at the time of insertion. The total resistance of the electrode system was about 700 ohms and P/QRS-ratio about 4 +/- 3. During an observation time ranging from 4 to 11 months there were no electrode dislocations. The electrodes were connected to the intended pacemakers without complications. In conclusion, the transvenous endocardial atrial lead, Medtronic 6961, shows attractive and promising qualities. The electrophysiological data recorded are suitable for the pacemakers in use. The electrode definitely deserves further evaluation.
美敦力6961导线已用于14例患者进行经静脉心房感知和/或起搏。该导线在远端配有硅胶小倒刺。导体线圈材料采用间隔缠绕以实现柔韧性。因此，该导线缺乏固有弹性，无需预成型的J形即可固定在右心耳内。该导线的临床经验令人鼓舞。与先前使用的有倒刺J形导线（美敦力6991）相比，该导线更容易引入并定位在右心耳中。新导线的小尺寸使得静脉的选择不那么关键，正常大小的颈外静脉或头静脉允许使用同一血管植入第二根心室导线。通过导线延长线，在电极插入后的四周内连续测定P波振幅、右心房刺激阈值、电极电阻和P/QRS比值。插入时的平均P波振幅为4.9±1.5mV（平均值±标准差）。一周后显著下降至最低平均水平3.09±1.1mV。从那时起只有微小变化。在仰卧位和正常呼吸时，P波振幅有±12%的自发变化。P波振幅受体位和最大呼吸运动的影响较小。一周后的刺激阈值为0.9±0.4V。后来阈值略有下降，但仍显著高于插入时。电极系统的总电阻约为700欧姆，P/QRS比值约为4±3。在4至11个月的观察期内，没有电极脱位。电极与预期的起搏器连接无并发症。总之，美敦力6961经静脉心内膜心房导线显示出有吸引力和有前景的特性。记录的电生理数据适用于正在使用的起搏器。该电极确实值得进一步评估。
