DVM, Cardiology Research Intern Department of Small Animal Clinical Sciences, University of Florida College of Veterinary Medicine Jacksonville, FL, United States
Abstract: Background - Scottish Deerhounds have a high prevalence of cardiac disease, representing 24% of deaths in UK populations with dilated cardiomyopathy particularly common. While Holter monitoring remains the gold standard for arrhythmia detection, normal reference intervals have not been established for this breed, and the utility of smartphone-based ECG devices (AliveCor) remains unexplored. Hypothesis/Objectives - We hypothesized that AliveCor recordings can serve as a screening tool for arrhythmia detection in dogs. Animals - 44 client-owned Scottish Deerhounds recruited by United States breed club. Methods - We recorded 24-hour Holter data to establish reference intervals and arrhythmia patterns in 44 Deerhounds. In a subset of 20 dogs, we compared AliveCor recordings to Holter data. Abnormalities were defined as >100 ventricular or atrial premature complexes on Holter (Dutton et al. 2022) and any arrhythmia on AliveCor. Each dog completed two consecutive 5-minute AliveCor recordings during sleep, rest, and post-exercise (10 minutes per activity), with additional recordings if needed (179 recordings; median 7 per dog; range: 4-32). Results - In 20 dogs with paired recordings, Holter identified abnormalities in 10 (50%) and AliveCor in 9 (45%), showing 85% agreement (k=0.7, p=0.002). AliveCor demonstrated 80% sensitivity and 90% specificity when referencing Holter. Agreement varied by activity, ranking highest during rest, 85% (k=0.7, p=0.001), post-exercise, 75% (k=0.5, p=0.019), and sleep, 70% (k=0.4, p=0.025). Conclusions and Clinical Importance - The frequency of arrhythmias in healthy Scottish Deerhounds was notable. AliveCor monitor appears to be a useful screening tool for dogs to prioritize testing with Holter monitoring.
