title: Noise reversion in paced dogs.
abstract: Pacemakers are commonly implanted by veterinary cardiologists in dogs with bradyarrhythmias. In the past, these pacemakers were placed with little attention to programming except for the basic heart rate. However, the availability of pacing programmers has permitted a better appreciation of the needs for proper and safe pacing in dogs. An awareness of the problems that can result from improper programming is imperative. We report the identification of noise reversion (inappropriate asynchronous pacing) in 42% of dogs consecutively paced (n = 19) at Cornell University during a 2 year period. Noise reversion is the operation that causes the pacemaker to switch to asynchronous pacing with repetitive refractory sensing. It was developed as a protective mechanism against noise being mistaken for cardiac events with the consequence of inhibition of pacing. However, in the dog, this operation can cause inappropriate, and potentially dangerous pacing. In the dog, this common complication is associated with the coexistence of a bradycardia and tachycardia. Proper programming of the refractory period (shortening) in conjunction with the sensitivity (decreasing the sensitivity) can eliminate noise reversion in dogs with both ventricular and atrial pacing.
authors.affiliation: Section of Cardiology - Department of Clinical Sciences College of Veterinary Medicine - Cornell University - Ithaca, New York, USA.
authors.forename: N Sydney
authors.initials: NS
authors.lastname: Moïse
authors.forename: Amara
authors.initials: A
authors.lastname: Estrada