Timing Cycles

This chapter provides a detailed description of "timing cycles" and approaches the subject by pacing mode and descriptions of other features that are used with some frequency that can alter the timing cycleIt outlines assessment of the paced electrocardiogram (ECG)Knowing the type of pacemaker, the programmed parameters, and the underlying rhythm necessitating pacing is important in interpreting the paced ECGVentricular asynchronous pacing is the simplest of all pacing modes, because there is no sensing and no mode of responseAtrial inhibited pacing, the atrial counterpart of ventricular inhibited pacing, incorporates the same timing cycles, with the obvious differences that pacing and sensing occur from the atrium and the pacemaker output is inhibited by a sensed atrial eventThe timing cycles of pacemakers apply to implantable cardioverter-defibrillators (ICDs) as wellThere are timing cycle issues and “lock-outs” that are specific to ICDs.