Worsening Heart Failure From Decreased Atrioventricular Synchronization Rate of a Leadless Pacemaker: Atrial Mechanical Oversensing.

BACKGROUND

Atrioventricular synchronous pacing with a leadless pacemaker is a therapy used in patients with atrioventricular block. However, atrial oversensing may cause an increase in heart rate, with resulting atrioventricular dyssynchrony.

CASE SUMMARY: A 90-year-old woman, who was treated with a leadless pacemaker 2 years earlier for a complete atrioventricular block, developed congestive heart failure. The electrocardiogram revealed an increase in heart rate with atrioventricular dyssynchronous pacing and a decrease in atrioventricular synchronization rate. A manual atrial mechanical test indicated dyssynchronized atrioventricular pacing secondary to atrial mechanical oversensing.

DISCUSSION: This case of heart failure exacerbation resulted from 1) the increase in heart rate with atrioventricular dyssynchrony caused by atrial mechanical oversensing and 2) the dyssynchronous pacing resulting from pacing-induced cardiomyopathy.

TAKE-HOME MESSAGES: Atrioventricular synchronization can vary with changes in cardiac structure and hemodynamics. It is important to assess atrioventricular synchrony repeatedly in electrocardiograms or rate histograms in the device.