Figure 16f

Unipolar (top) and bipolar (bottom) intracardiac electrograms (IEFMS) from a patient with a ventricular pace, aker whose underlying rhythm is atrial fibrillation. Note that the bipolar signal is sharper, with less sensing of far field ventricular activity or T waves. With either unipolar or bipolar electrograms, direct measurement of the electrogram is possible. Each division on the left represents 1 mV. Therefore, the unipolar intra cardiac electrogram is 2 to 3 mV frombaseline to peak. The bipolar electrogram would be expected to be approximately 2 mV.