Copie X, Blankoff I, Hnatkova K, Fei L, Camm A J, Malik M
Service de cardiologie (Pr Guize), hôpital Broussais, Paris.
Arch Mal Coeur Vaiss. 1996 Jun;89(6):723-7.
The authors studied the possibility of improving the reproducibility of the signal averaged ECG by increasing the number of averaged QRS complexes. One hundred patients were included in the study. In each cases, 400 QRS complexes were recorded on twice, consecutively, in strictly identical conditions. During each recording, the total duration of the amplified and averaged QRS complex (tQRS), the duration of the terminal signal below 40 microV (LAS) and the root mean square of the amplitude of the last 40 ms (RMS) were determined for 100, 200, 300 and 400 recorded QRS complexes. The presence of late potentials was defined as the positivity of two of the following criteria: tQRS > 114 ms, LAS > 38 ms, RMS < 20 microV. The number of contradictory diagnostic conclusions between two successive recordings of the same duration decreased progressively with the number of averaged QRS complexes: 10 for 100 QRS, 10 for 200 QRS, 9 for 300 QRS and 6 for 400 QRS complexes, but this improvement was not statistically significant. The absolute differences of tQRS and RMS between two successive recordings of the same duration were statistically different for the four durations of recording (p = 0.05) and there was a tendency towards statistical significance for LAS (p = 0.09). The best quantitative reproducibility of the 3 parameters was obtained with the recording of 300 QRS complexes. In conclusion, the reproducibility of the signal averaged ECG is improved when the number of average QRS complexes is increased. The authors' results suggests that reproducibility this is optimal with the amplification and averaging of 300 QRS complexes.
作者研究了通过增加平均QRS复合波数量来提高信号平均心电图可重复性的可能性。该研究纳入了100名患者。在每种情况下，在严格相同的条件下连续两次记录400个QRS复合波。在每次记录期间，针对100、200、300和400个记录的QRS复合波，测定放大并平均后的QRS复合波的总持续时间（tQRS）、低于40微伏的终末信号持续时间（LAS）以及最后40毫秒振幅的均方根（RMS）。晚电位的存在定义为以下标准中的两项为阳性：tQRS>114毫秒、LAS>38毫秒、RMS<20微伏。相同持续时间的两次连续记录之间矛盾诊断结论的数量随着平均QRS复合波数量的增加而逐渐减少：100个QRS复合波时有10个矛盾结论，200个QRS复合波时有10个，300个QRS复合波时有9个，400个QRS复合波时有6个，但这种改善无统计学意义。相同持续时间的两次连续记录之间tQRS和RMS的绝对差异在四个记录持续时间上均有统计学差异（p=0.05），LAS有统计学意义的趋势（p=0.09）。记录300个QRS复合波时，这三个参数获得了最佳的定量可重复性。总之，增加平均QRS复合波数量时，信号平均心电图的可重复性得到改善。作者的结果表明，对300个QRS复合波进行放大和平均时，可重复性最佳。
