Electrocardiographic abnormalities are associated with seropositive Trypanosoma cruzi infection status using a simplified cardiac diagnostic evaluation in dogs.

Abstract

To describe associations between cardiac abnormalities and Trypanosoma cruzi serostatus by use of a simplified diagnostic evaluation in dogs at risk for T cruzi infection. A prospective, cross-sectional study was performed using a simplified diagnostic evaluation including high-sensitivity cardiac troponin I, 30-second ECG, and echocardiogram with 7 variables in 46 client-owned dogs from high-risk environments. Dogs were categorized as serologically positive (SP), negative (SN), or discordant (SD) by use of 2 antibody tests. Functional evaluation of cardiac health scores and blood PCR were obtained. Dogs were SP (n = 19), SN (17), and SD (10), with 9 PCR positive (7 SP, 1 SN, 1 SD). Troponin was above reference range in 6 of 46 (4 SP, 1 SN, 1 SD), and functional evaluation of cardiac health scores were 0 in all dogs. Conduction system abnormalities (prolonged interval durations, second-degree atrioventricular block, splintered QRS complex) and ventricular arrhythmias were documented in 8 (7 SP, 0 SN, 1 SD). Twenty-six (12 SP, 8 SN, 6 SD) had echocardiographic abnormalities, most often myxomatous mitral valve disease (MMVD) and left ventricular enlargement. Seropositive dogs were significantly older and had a higher likelihood of MMVD. Conduction system abnormalities were associated with positive serostatus. Echocardiographic abnormalities were complicated by MMVD and did not distinguish between serostatus. An ECG with assessment and detailed measurement of complexes and cardiac troponin I are simple tests to perform with abnormalities detected in seroreactive dogs. Electrocardiographic abnormalities in high-risk or seroreactive dogs should prompt further evaluation and monitoring of T cruzi infection.