Kroll Maja, Kriebel Thomas, Windhagen-Mahnert Britta, Franzbach Birgit, Jux Christian, Zutz Martina, Tebbenjohanns Jürgen, Paul Thomas
Department of Pediatric Cardiology and Pediatric Intensive Care Medicine, Hannover Medical School, Hannover, FR Germany.
Pacing Clin Electrophysiol. 2003 Oct;26(10):1970-8. doi: 10.1046/j.1460-9592.2003.00304.x.
Clinical data using the noncontact mapping system (Ensite 3000) suggest that characteristics of the reconstructed unipolar electrograms may predict the origin of electrical activation within the atrial and ventricular walls (endocardial vs myocardial vs epicardial origin). Experimental data are lacking. In ten open-chest pigs (mean body weight 62 kg) cardiac pacing was performed at a cycle length of 600 ms with a pulse width of 2 ms and twice diastolic threshold from the endo-, the myo-, and the epicardium, respectively. Pacing was undertaken at three right atrial and three left ventricular sites, and cardiac activation was recorded with the Ensite system. Reconstructed unipolar electrograms at the location of earliest endocardial activation assessed by color coded isopotential maps were analyzed systematically for differences in morphology. The positive predictive value of atrial electrograms exhibiting an initial R wave during pacing for a subendocardial origin (i.e., myocardial or epicardial) was 0.96. The negative predictive value was 0.48. Electrograms generated during myocardial pacing exhibited increased maximal negative voltage and maximal dV/dt (-3 +/- 1.8 mV, -798 +/- 860 mV/ms, respectively) than the electrograms obtained during endocardial (-2 +/- 1 mV, -377 +/- 251 mV/ms, respectively) and epicardial pacing (-2.1 +/- 0.7 mV, -440 +/- 401 mV/ms, respectively, P<0.01 for both parameters). During pacing at the left ventricular wall, occurrence of an initial R wave did not differ significantly between electrograms reconstructed during endocardial and subendocardial pacing. All other characteristics of the unipolar ventricular electrograms analyzed, except latency, did not differ significantly when compared to stimulation depth. Morphological characteristics of unipolar electrograms generated by the noncontact mapping system during pacing of the atrium allowed for discrimination of an endocardial versus a subendocardial origin of activation. At the ventricular level, characteristics of unipolar electrograms did not predict the origin of cardiac activation in this experimental setting.
使用非接触式标测系统（Ensite 3000）的临床数据表明，重建单极电图的特征可能预测心房和心室壁内电激动的起源（心内膜起源与心肌起源与心外膜起源）。目前缺乏实验数据。在10只开胸猪（平均体重62千克）中，分别从心内膜、心肌和心外膜以600毫秒的周期长度、2毫秒的脉宽和两倍舒张阈值进行心脏起搏。在右心房的三个部位和左心室的三个部位进行起搏，并用Ensite系统记录心脏激动情况。通过彩色编码等电位图评估最早心内膜激动部位的重建单极电图，系统分析其形态差异。起搏时心房电图出现初始R波对于心内膜下起源（即心肌或心外膜）的阳性预测值为0.96。阴性预测值为0.48。心肌起搏期间产生的电图比心内膜起搏（分别为-2±1毫伏，-377±251毫伏/毫秒）和心外膜起搏（分别为-2.1±0.7毫伏，-440±401毫伏/毫秒）期间获得的电图表现出更大的最大负电压和最大dV/dt（分别为-3±1.8毫伏，-798±860毫伏/毫秒，两个参数P均<0.01）。在左心室壁起搏期间，心内膜起搏和心内膜下起搏期间重建的电图之间初始R波的出现没有显著差异。除潜伏期外，分析的单极心室电图的所有其他特征与刺激深度相比没有显著差异。心房起搏期间非接触式标测系统产生的单极电图的形态特征有助于区分激动的心内膜起源与心内膜下起源。在心室水平，在本实验环境下单极电图的特征不能预测心脏激动的起源。
