ACE and COVID-19: For example, a study by Sonaglioni et al. showed increased comorbidity burden, elevated serum levels of inflammatory biomarkers such as the neutrophil-to-lymphocyte ratio (NLR), and undertreatment with ACE inhibitors (ACEis) and angiotensin II receptor blockers (ARBs) contributed to the development of atrial arrhythmias and unfavorable outcomes in COVID-19 patients.