Cardiac Autonomic Modulation and the Occurrence of Arrhythmic Events in Brachycephalic Dogs: A Scoping Review

Abstract

Brachycephalic obstructive airway syndrome (BOAS) is a condition characterized by anatomical obstructions of the upper airways that impair airflow and lead to ventilatory dysfunction in dogs with broad and short skulls. This condition may also contribute to the occurrence of arrhythmias associated with increased vagal tone, such as sinus pauses or atrioventricular blocks. In advanced stages, pulmonary hypertension and cardiac remodeling may occur, predisposing affected dogs to more complex arrhythmias, including atrial fibrillation. This study aimed to map the available scientific evidence regarding autonomic cardiac activity and the presence of arrhythmias in brachycephalic dogs. This scoping review was conducted according to the standards of the Joanna Briggs Institute (JBI) and adhered to the Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews methodological guidance (PRISMA-ScR). The databases CABI, BVS, Embase, MEDLINE/PubMed, SciELO, Scopus, and Web of Science. were used to search for scientific evidence published to date. The search strategy included the terms: “airway obstruction”, “brachycephalic dogs”, “heart rate variability”, “parasympathetic nervous system”, and “respiratory sinus arrhythmia”. The research identified 769 articles, of which 11 met the criteria and were included. Each article was analyzed, and its information was characterized according to four domains of interest: general study information, methodological design of the studies, variables analyzed and diagnostic strategies applied, and main findings and conclusions. This scoping review emphasizes the increasing scientific interest in the relationship between brachycephalic breed morphology and cardiac autonomic modulation in dogs. Although there are a limited number of studies with methodological diversity, the evidence suggests that vagal overstimulation resulting from chronic upper airway obstruction in these breeds significantly influences heart rate and rhythm modulation. Future research should focus on achieving methodological standardization, detailed morphometric evaluations, and utilizing long-term monitoring techniques to improve diagnostic accuracy and clinical relevance.