经食管信号平均心电图记录窦房结电图的临床研究

Clinical Study of Sinus Node Electrogram by Transesophageal Signal Averaging Technique

探讨无创性经食管信号叠加直接记录窦房结电位 (SNP)的技术 ,对 2 5 6例食管电生理检查窦房结传导时间(SACT)和窦房结恢复时间 (SNRT)均在正常范围的患者 ,其中男 14 2例、女 114例 ,年龄 4 4 .2± 12 .4 (10～ 74 )岁进行检测。采用自制三导心电微电位检测仪将食管导联的信号放大 (增益达到 10 0 μV/cm)、滤波 (0 .1～ 5 0Hz) ,16位模 /数 (A/D)转换 ,系统采样频率 2kHz,对信号进行叠加 ,189例 (74 % )记录到食管SNP。所测信号叠加食管SNP为P波前的低幅、低频波 ,可见有两种形态 :园顶型 (6 0 % )和上斜型 (4 0 % )。所测窦房传导时间为 83.3± 2 6 .7ms ,分布范围为 2 3～ 118ms;波幅为 3.5～ 2 7.7μV ;dv/dt为 0 .4 3～ 1.93mV/s。笔者认为在适当的滤波、高增益和抗基线漂移技术条件下 ,利用经食管信号叠加技术 ,大多数窦房结功能正常的患者可直接记录到食管SNP。

We have developed a noninvasive transesophageal signal averaging technique for direct recording of sinus node potential (SNP).In this study,the signals from lead I,surface averaged lead and esophagus averaged lead were amplified(up to 100 μV/cm),filtered(0.1-50 Hz),AD converted to 16 bit accuracy at a sampling rate of 2kHz and averaged by using the three channel low-noise amplifier.SNPs were recorded from 189 of 256 patients with normal sino-atrial conduction time and sinus node recovery time(74%),comparable to that (46%) recorded by conventional transesophageal technique,142 were male and 114 were female ranging in age form 10-74 year (mean 44.2±12.4 years).The signal averaged esophageal SNPs were deflections of low-amplitude and low-frequency preceding the Pwave.Two morphologies,the domed wave (114 of 189 patients,60%)and the smooth upstroke slope (75 of 189 patients,40%),could be seen.The directly recorded sinoatrial conduction time was 83.3±26.7 msec,ranged from 23-118 msec,amplitude was 3.5-27.7 μV and dv/dt was 0.43-1.93 mV/sec. The sinoatrial conduction time recorded by the transesophageal catheter technique was comparable to that (80.4±18.1 msec)recorded by the transvenous catheter method perfectly. We think that signal averaged sinus node electrogam could be recorded in sinus rhythm in most patients with normal sinus node function and proper filter settings,high amplification and anti-drift technique are important in recording signal averaged esophageal sinus node electogram.