Lehmann Michael H, Katona Aimee M
Department of Internal Medicine, Division of Cardiovascular Medicine, University of Michigan School of Medicine, Ann Arbor, Michigan, USA.
J Emerg Med. 2012 Oct;43(4):584-92. doi: 10.1016/j.jemermed.2012.01.022. Epub 2012 Apr 14.
Misplacement of right precordial electrocardiogram (ECG) electrodes superiorly is a prevalent procedural error that may lead to false findings of T-wave inversion or QS complexes in V2-possibly triggering wasteful utilization of health care resources. Standard technique for proper placement of V1-V2 entails initial palpation for the sternal angle, pointing to the second intercostal space (ICS), followed by lead fixation at the fourth ICS.
Because adherence to this approach may be limited by lack of a visual landmark for the second ICS, we assessed an alternative technique.
The evaluated technique involved placement of the patient's hand up against the base of his/her neck (H→N maneuver) to help demarcate visually a specific point "X" on the chest.
Of 112 patients studied, "X" landed on the first rib in 2.7%, first ICS in 7.1%, second rib in 56.3%, second ICS in 33.0%, and third rib in 0.9%. Thus, in 89.3% (95% confidence interval 83.6-95.0%) of cases (93.3% of men, 84.6% of women; p=0.13), the second ICS could be identified by H→N via the following simple rule: Utilize "X" if it overlies an ICS; or the immediately subjacent ICS if "X" overlies a rib.
The H→N maneuver provides a primarily visual approach to identifying the second ICS and, thereby, the fourth ICS for affixing V1-V2. If the present initial experience is confirmed, H→N might merit consideration as an educational tool to promote anatomically correct placement of these precordial leads, a prerequisite to diminishing the incidence of ECG procedure-related "septal ischemia/infarction."
右胸前心电图（ECG）电极向上放置错误是一种常见的操作失误，可能导致V2导联出现T波倒置或QS波群的错误结果，这可能会引发医疗资源的浪费性使用。正确放置V1 - V2导联的标准技术是先触摸胸骨角，其指向第二肋间间隙（ICS），然后将导联固定在第四肋间间隙。
由于遵循这种方法可能会受到缺乏第二肋间间隙视觉标志的限制，我们评估了一种替代技术。
所评估的技术包括将患者的手靠在其颈部底部（H→N动作），以帮助在胸部视觉上划定一个特定点“X”。
在研究的112例患者中，“X”落在第一肋骨上的占2.7%，第一肋间间隙的占7.1%，第二肋骨上的占56.3%，第二肋间间隙的占33.0%，第三肋骨上的占0.9%。因此，在89.3%（95%置信区间83.6 - 95.0%）的病例中（男性为93.3%，女性为84.6%；p = 0.13），可以通过H→N动作根据以下简单规则识别第二肋间间隙：如果“X”覆盖在一个肋间间隙上，则使用该间隙；如果“X”覆盖在一根肋骨上，则使用其紧邻的下方肋间间隙。
H→N动作提供了一种主要通过视觉来识别第二肋间间隙的方法，从而确定用于固定V1 - V2导联的第四肋间间隙。如果目前的初步经验得到证实，H→N动作可能值得作为一种教育工具来促进这些胸前导联在解剖学上的正确放置，这是减少与心电图操作相关的“间隔缺血/梗死”发生率的一个前提条件。
