Rautaharju P M, Seale D, Prineas R, Wolf H, Crow R, Warren J
J Electrocardiol. 1978 Oct;11(4):321-30. doi: 10.1016/s0022-0736(78)80137-x.
An analytical study was performed to estimate the magnitude of the visual Q wave duration bias produced by pressurized ink round stylus electrocardiographic (ECG) recorders. With a paper speed of 25 mm/sec and the ECG tracing width of 0.25 mm, the visually measured Q waves are on the average 8 msec too short. The corresponding error with the older type flat stylus recorder is less than 2 msec. Considerable differences can thus be anticipated in the frequency of observed ECG abnormalities in studies which use different types of electrocardiographs. The effect of the visual Q wave duration measurement bias on the diagnostic ECG classification was investigated in a group of 237 patients with old myocardial infarction and 299 subjects with no clinical evidence of infarction. An 8 msec measurement bias toward too short Q wave duration was observed to result in a potential loss of diagnostic accuracy of about 25% in some ECG coding categories. As a corrective procedure, it is recommended that the baseline width produced by a round recording stylus of uniform thickness irrespective of the vertical deflection velocity should be less.
进行了一项分析研究，以估计加压墨水圆形记录笔式心电图（ECG）记录仪所产生的视觉Q波时限偏差的大小。在纸速为25mm/秒且心电图描记宽度为0.25mm的情况下，视觉测量的Q波平均短8毫秒。老式扁平记录笔式记录仪的相应误差小于2毫秒。因此，在使用不同类型心电图仪的研究中，可以预期观察到的心电图异常频率会有相当大的差异。在一组237例陈旧性心肌梗死患者和299例无梗死临床证据的受试者中，研究了视觉Q波时限测量偏差对诊断性心电图分类的影响。观察到向Q波时限过短方向的8毫秒测量偏差会导致某些心电图编码类别中诊断准确性潜在损失约25%。作为一种纠正措施，建议无论垂直偏转速度如何，由厚度均匀的圆形记录笔产生的基线宽度应更小。
