Beluque, T.; Camacho, A. A.; Ampuero, R. N.; Braz, J. B.; Kirnew, M. D.; Canola, R. A. M.; Carvalho, E.; Sousa, M. G. Heart Rate Variability and Quality of Life in Dogs With Mitral Valve Disease Treated With Metoprolol . Braz. J. Vet. Med. 2021, 43, e003020.