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Dual Chamber Pacing example one



This strip shows dual chamber pacing at its most straightforward.   With each beat, an initial pacer spike is followed by an oddly shaped P-wave (atrial stimulation and response), there is a short pause (a predetermined P-R interval, in this case 0.15 seconds in length), then a second pacer spike is followed by a wide QRS complex resembling a PVC (ventricular stimulation and response).  There follows another pause, and the cycle repeats.  This pacer is set to produce a beat every 0.96 seconds, producing a heart rate of 62.5 beats per minute.   (It was probably intended to set a rate of 60.)  So, we see here sensing of both the atria and ventricles (in this case sensing of no activity) and dual stimulation.  This pacer was in fact also programmed to respond to native atrial and ventricular activity by inhibiting its own activity.   Thus, this is DDD pacing.