Arrhythmias evoked by airway nociceptive reflexes in healthy and cardiovascular diseased rats (1169.8)

Abstract

Inhalation of particulate matter (PM) increases cardiovascular (CV) morbidity and mortality by increasing the risk of arrhythmias in susceptible individuals. This is believed to occur through autonomic nervous system imbalance following activation of pulmonary afferent C‐fibers. However, it is unclear how pulmonary‐cardiac reflexes specifically contribute to these arrhythmias. To characterize this, we selectively activated pulmonary C‐fibers via gating of ion channels TRPV1 and TRPA1 (which can be activated by PM) using capsaicin and mustard oil (MO), respectively. We implanted 15 week old Sprague‐Dawley (SD) and Spontaneously Hypertensive (SH) rats with a radiotelemetric ECG device. ECG was recorded for 30 minutes during exposure of the rats to ambient air, nebulized vehicle, and either capsaicin (600 μM) or MO (30 mM). We found an increase in dropped beats and arrhythmias such as second‐degree AV block and premature ventricular contractions in both SD and SH rats upon irritant inhalation. Furthermore, SH rats had a significant increase in brady/tachy events upon agonist inhalation. We conclude that lung C‐fiber reflexes evoke arrhythmias, which in CV disease may contribute to morbidity and mortality.