de Micheli Alfredo, Medrano Gustavo A, Aranda Alberto
Instituto Nacional de Cardiología Ignacio Chávez, INCICH, Juan Badiano No. 1 Col. Sección XVI, Tlalpan 14080 México, D.F.
Arch Cardiol Mex. 2003 Apr-Jun;73(2):135-42.
Chronological and spatial characteristics of the main resultant vectors of the left atrial and ventricular depolarization in normal conditions and in presence of hypertrophy, due to a sustained overload, are described. The coexistence of interatrial, intraatrial, and intraventricular conduction disorders can modify the orientation of these vectors. The main electrocardiographic sign of left atrial hypertrophy is a P wave duration > 0.10 sec in adults. In case of left ventricle hypertrophy, the time of onset of the intrinsicoid deflection (TOID) is prolonged in the near left unipolar leads, and the S wave voltage is increased in opposite regions, i.e. in the right precordial or transitional leads. It is necessary to bear in mind other useful electrocardiographic signs. Hence, absence of the right basal vector (IIId) manifestation in a clockwise rotating heart is probably due to an increase in the basal electromotive forces of the left ventricle (vector IIIi) due to hypertrophy or ipsilateral ventricular conduction disorders. For a correct evaluation of these signs, it is mandatory to perform a rational analysis of the traings, not just a stereotyped electrical exploration. Besides it is very important to determine the Q-Tc interval in the left unipolar leads to establish whether, in these leads, the inverted T wave is of secondary type (normal Q-Tc) or of primary type (prolonged Q-Tc) due to a coexisting subepicardial or transmural ischemia. From these considerations, the usefulness of the thoracic circle and high abdominal unipolar leads is inferred.
描述了正常情况下以及由于持续负荷过重导致肥厚时左心房和心室去极化主要合成向量的时间和空间特征。心房内、心房内和心室内传导障碍的共存可改变这些向量的方向。成人左心房肥厚的主要心电图表现是P波时限>0.10秒。左心室肥厚时，近左单极导联中初始向量偏转（TOID）的起始时间延长，而在相对区域，即右胸前导联或过渡导联中S波电压升高。必须牢记其他有用的心电图表现。因此，顺时针旋转心脏中右基底部向量（IIId）表现缺失可能是由于肥厚或同侧心室传导障碍导致左心室基底部电动势（向量IIIi）增加。为了正确评估这些表现，必须对心电图进行合理分析，而不仅仅是刻板的电检查。此外，确定左单极导联中的Q-Tc间期非常重要，以确定在这些导联中，倒置T波是继发型（正常Q-Tc）还是原发型（延长的Q-Tc），这是由于并存的心外膜下或透壁性缺血所致。基于这些考虑，可以推断出胸圈导联和高腹部单极导联的有用性。
