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This is an EKG recording from and elderly woman with complete heart block. She is having an Intermedics Quantum pacemaker (VVI) replaced with a Medtronic Preva DDD pacemaker. The Quantum is implanted in the left pectoral area and is set to V00 mode at 72/min, the Preva is implanted in the right pectoral area and set to VVI at 40/min. A magnet is placed over the Preva near the middle of the tracing. Both pacemakers are in a unipolar mode.

This is an interesting tracing as the two pacemaker leads where in a similar position in the left ventricle. This is clearly seen as the QRS morphology for both types of paced beats are identical. The morphology is a left bundle like pattern consistent with implantation of the electrode in the right ventricle as desired. Of interest is the difference in the polarity in lead I of the pacer spikes. The spike is positive for the pacer in the left pectoral region and negative for the pacer in the right pectoral area. As the pacemaker is the positive pole and the tip of the electrode the negative pole, this makes sense as lead I has a positive pole on the left shoulder and a negative one on the right.


Case reports by Michael Rosengarten


EKG World Encyclopedia , courtesy of Michael Rosengarten BEng, MD.McGill




Michael Rosengarten BEng, MD.McGill


Creative Commons Attribution Noncommercial Share-Alike License

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current10:44, 21 February 2012Thumbnail for version as of 10:44, 21 February 20123,004 × 1,277 (840 KB)DarrelC (talk | contribs)

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