[O i]6300 Å continuum subtracted position velocity (PV) diagrams of five sources exhibiting strong HVC. The straight line indicates the position of the continuum while red dots highlight the peaks of the blue- and red-shifted HVC (i.e. HVB and HVR, respectively) and of the LVC. The HVC peaks are systematically shifted with respect to the continuum position, showing that this component is extended.