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The reason why the pacer was pacing at 75/min in the DDD mode was because there is a supraventricular tachycardia (note atrial activity, marked with the turquise arrows, moving through the ventricular complexes) at about 150/min and the DDD pacer was producing 2:1 A/V block. In tracing above with the pacemaker set to a VVI mode, the pacemaker no longer senses the atrium and paces at the set rate of 70/min.
EKG World Encyclopedia http://cme.med.mcgill.ca/php/index.php , courtesy of Michael Rosengarten BEng, MD.McGill
Michael Rosengarten BEng, MD.McGill
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|current||21:56, 16 February 2012||3,004 × 673 (683 KB)||DarrelC|