Altered Heart-Rate Variability in Asthmatic and Healthy Volunteers Exposed to Concentrated Ambient Coarse Particles
Source: Inhalation Toxicology, Volume 16, Numbers 6-7, Numbers 6-7/June 2004 , pp. 335-343(9)
Publisher: Informa Healthcare
Abstract:Twelve mildly asthmatic and four healthy adults were exposed to filtered air (FA) and concentrated ambient coarse particles (CCP) supplied to a whole-body exposure chamber via a coarse particle concentrator with 15 parallel virtual impactors. Exposures were conducted in a Los Angeles suburb with high levels of motor-vehicle pollution and lasted 2 h with intermittent exercise. Mean CCP concentration was 157μg/m3(range: 56–218μg/m3) measured by continuous monitoring with a tapered-element oscillating microbalance (TEOM). On average, 80%of mass was coarse (2.5–10μm aerodynamic diameter) and the rest < 2.5μm. Relative to FA, CCP exposure did not significantly alter respiratory symptoms, spirometry, arterial oxygen saturation, or airway inflammation according to exhaled nitric oxide and total and differential cell counts of induced sputum. After CCP exposure, Holter electrocardiograms showed small (p< .05) increases in heart rate and decreases in heart-rate variability, which were larger in healthy than in asthmatic subjects. Cardiac ectopy did not increase. In conclusion, acute exposure to elevated concentrations of ambient coarse particles elicited no obvious pulmonary effects but appeared to alter the autonomic nervous system of the heart in adult volunteers.
Document Type: Research Article
Affiliations: 1: University of Southern California Keck School of Medicine, Los Angeles, and Los Amigos Research and Education Institute, Downey, California, USA 2: Los Amigos Research and Education Institute, Downey, California, USA 3: University of Southern California School of Engineering, Los Angeles, California, USA 4: Department of Medicine, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
Publication date: June 1, 2004