This case report is kindly provided by Michael Rosengarten from McGill and is part of the McGill Cases. These cases come from the McGill EKG World Encyclopedia.
This is a threshold test of a VVI pacemaker. Note the effect of the PVCs, the first of which competes with the pacer stimulus and suggests capture when there may be none. Also note that the second to last 0.6 volt pulse captures the ventricle but the last, with the same pulse width, does not.
