Characterization of the 16 blanking periods of the Medtronic GEM DR dual chamber defibrillators.

We determined the blanking periods of the Medtronic GEM DR dual chamber defibrillators by using a simulator to deliver signals mimicking arrhythmias into external devices programmed to various settings. The blanking periods for the tachycardia and bradycardia functions were measured in the atrial and ventricular channels after a paced atrial event, sensed atrial event, paced ventricular event and sensed ventricular event, adding to a total of 16 blanking periods. Our findings complement the incomplete or unclear specifications published by the manufacturer. Accurate knowledge of blanking periods is essential for the interpretation of device function.