Usefulness of Activity: Sensing Rate Responsive Pacemaker

Lee, Woong Ku; Park, Seung Jung; Cho, Seung Yun; Shim, Won Heum

Abstract

Conventional dual chamber pacing (DDD) preserves atrioventricular synchrony but depend on appropriate sinus node function to achieve physiological heart rate with exercise by atrial tracking. Other indirect indicators of metabolic demand have been used to modulate pacing rate increases with exercise including sensing of pH, respiratory rate, ventricular repolarization and oxygen saturation. The activity sensing approach is unique in that noise generated by activity modulates the response and empirical programming of the unit allows for attaining the desired rate for a given level of activity. Physiologic rate increases can be obtained in patients with sinus node dysfunction or even atrial fibrillation. The lead can either be positoned in the atria for patients without atrial fibrillation or AV conduction disturbance or in the ventricle. We present two cases of rate responsive pacing using the Activitrax.