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While the defibrillator lead appears to be in an appropriate position in the PA view (1A), the 12-lead ECG during pacing would be unusual for a RV position. It shows a right bundle branch block (RBBB) pattern which is more consistent with LF pacing. A ‘pseudo RBBB’pattern can rarely be seen with RV apical pacing, 1 2 but it would be unusual for the transition to be so late in V4 as in this case. The ‘injury current’demonstrated an absence of ST elevation which may be consistent with an extracardiac or CS location. The acquisition during CS venography (see online supplementary video) shows clearly that the lead is in the MCV. Figure 2 shows the PA and LAO views of the lead after repositioning in the RV apex. Only the LAO view clearly distinguishes the RV apical from the MCV position. When repositioned in the RV apex, there is a change in the ECG during pacing (LBBB morphology) and ST elevation in the …