Fig. (4).

ECG/VCG aspects of left bundle branch block. VCG criteria in the HP: Narrow, long QRS loop, and with morphology usually in “eight”; the QRS loop duration is ≥120 ms; the QRS loop shape is elongated and narrow; the main body of the QRS loop is inscribed posteriorly and to the left within the range of - 90 to - 40°; maximal vector of QRS located in the left posterior quadrant (between –40º to -80º) and of increased magnitude (>2 mV); the main portions of the QRS loop of CW rotation. CCW rotation may indicate parietal CLBBB or association with lateral infarction or severe left ventricular hypertrophy (LVH); the efferent limb (II) located to the right related to the afferent limb (III and IV); conduction delay noted in the mid and terminal portion; the main body of QRS loop is inscribed CW; the magnitude of the max QRS vector is increased above normal exceeding 2mV; the ST segment and T wave vector are directed rightward and anteriorly; the T loop of CCW recording. The CW rotation of T wave in this plane suggests CLBBB complicated with infarction or LVH [33]. (A higher resolution / colour version of this figure is available in the electronic copy of the article).