Pacemakers and Settings in the Athlete

A 62-year-old man with a history of atrial fibrillation (AF) and atypical atrial flutter presents to the clinic. He had previously undergone multiple catheter ablations targeting both the right atrium (RA) and left atrium. Because of recurrent atrial arrhythmia, he opted to undergo a Cox MAZE IV surgical AF ablation. His postoperative course was notable for periods of apparent complete heart block prompting implantation of a dual-chamber permanent pacemaker (PPM). During the procedure, a lead in the region of the sinus node could sense sinus activity but could not pace the atrium or ventricle, consistent with electrical sinus node isolation. The atrial lead was instead placed away from the sinus node to use atrial pacing and native conduction; however, the device consequently could not sense the underlying sinus activity.

He is a retired college athlete who exercises >5 days per week with activities including running, hiking, swimming, and biking. He reports exertional intolerance, particularly when trying to hike quickly uphill. His PPM interrogation shows a rate histogram (Figure 1).

Figure 1

Figure 1
Figure 1: Atrial Rate Histogram in the Clinic. Courtesy of Hall D, Mikhova K, Cooper DH, Husaini M.

Is his PPM likely to be contributing to his symptoms and, if so, what changes could be made to improve his exercise capacity?

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