To the Editor: The medical mystery in the June 13 issue1 involveda 76-year-old man with sinus node disease who was evaluatedafter an episode of syncope and who received a single-chamberpacemaker through the left subclavian approach. The medial pathwayof the pacing lead on the chest film (Figure 1), coupled withthe finding of right bundle-branch block on the paced electrocardiogram(Figure 2), confirms that the lead had been passed by meansof the subclavian artery through the ascending aorta, acrossthe aortic valve, and into the left ventricle. A new, dual-chamberpacemaker was placed through the right side of the chest, andonce stable pacing had been established, the left-sided pacemakerpocket was opened, the generator was removed, and the lead wasretracted to the level of the subclavian artery but temporarilyleft in place to avoid arterial bleeding. The residual fragmentof the lead was then removed by a vascular surgeon, who repaireda laceration of the inferior margin of the subclavian arterycaused by the original procedure.
Figure 2. Electrocardiogram Showing Right Bundle-Branch Block.
J. Warren Harthorne, M.D. Igor Palacios, M.D. Massachusetts General Hospital Boston, MA 02114
Editor's note: We received 258 responses to this medical mystery;79 percent of responses indicated that the pacemaker lead haderroneously been placed into the left ventricle. Other responsesincluded insertion of the pacemaker into the coronary sinus(7 percent), perforation of the interventricular septum by thelead (3 percent), and insertion of the lead into the right ventricle(2 percent).
References
Harthorne JW, Palacios I. A medical mystery. N Engl J Med 2002;346:1878-1878. [Free Full Text]
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