Improved signal quality using solid tip vascular placement of ECG leads in rats (LB667)

Abstract

Continuous data recording, using telemetry systems, has proven to be the preferred way of collecting electrocardiogram (ECG) data in conscious freely moving animals. In small animals, however; the resulting recordings can have indistinguishable P, Q, R, S and T segments due to low signal to noise ratios. In large animals, similar challenges have been addressed by equipping wireless telemetry devices with an intravascular negative electrode, or solid tip lead (STL). The purpose of this study was to determine if STLs could be implanted in rats and result in improved ECG signal quality when compared to conventional subcutaneous leads. Two groups of Sprague Dawley rats, one with conventional lead placement (subcutaneous) and the other using the STL (vascular) were surgically implanted. ECG data were collected multiple times over a one year period. Signal quality was qualitatively and quantitatively evaluated between the STL and conventional lead groups, using a side by side visual comparison, and automated Q, R, S and T match percentage, by an experienced ECG analyst. ECG data collected with a STL was observably clearer when compared to the conventional lead group. At the completion of the study, the rats implanted with STLs were subjected to thorough necropsies. A histological examination of the tissue surrounding the STL was completed. In conclusion, STLs were successfully implanted in rats, resulting in improved signal quality with no detrimental evidence of inflammation noted at necropsy. The two ECG signals were compared for ease of automated analysis through comparison of Q, R, S and T match. This application could be especially useful in other small animal models such as the ferret or guinea pig, to increase ECG quality and improve automated ECG analysis.