“…The more likely explanation is that the tip of the pacing electrode is in the most posterior portion of the right ventricle, on the interventricular septum, relatively far from the chest wall and early precordial chest leads (ie, V 1 –V 3 ). 6 , 7 Klein and colleagues 2 reported that recording an ECG with the V 1 and V 2 leads in the fifth or sixth intercostal space unmasks an LBBB pattern with true apical right ventricular pacing. 2 This maneuver was performed in both patients.…”