Spontaneous cardiac arrhythmias recorded in three experimentally- and drug-naive laboratory species (canine, primate, swine) during standard pre-study screening

The purpose of this study was to collect and estimate the general prevalence of spontaneous irregularities in cardiac rhythms in three standard laboratory animal species: Beagle dog ( N = 2450), cynomolgus monkey ( N = 1563), and domestic swine ( N = 704) during standard preclinical screening. Standard prestudy Lead II hardwire ECG tracings were collected in purpose-bred, drug-, and experimentally-naive animals following receipt from an institutionally-approved vendor and prior to placement onto general toxicology or safety pharmacology studies over the course of 18 months. The ECGs were independently reviewed by two veterinary cardiologists/internists for the presence or absence of arrhythmias (dysrhythmia), conduction disturbances, or other normal variants or clinically significant waveform changes. Greater than 98% of all ECGs recorded in animals bred for laboratory use demonstrated sinus rhythms without morphologic abnormalities or arrhythmias.