title: Altered heart-rate variability in asthmatic and healthy volunteers exposed to concentrated ambient coarse particles.
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 157 microg/m(3) (range: 56-218 microg/m(3)) measured by continuous monitoring with a tapered-element oscillating microbalance (TEOM). On average, 80% of mass was coarse (2.5-10 microm aerodynamic diameter) and the rest <2.5 microm. 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.
authors.affiliation: University of Southern California Keck School of Medicine, Los Angeles, USA. hgong@dhs.co.la.ca.us
authors.forename: Henry
authors.initials: H
authors.lastname: Gong
authors.forename: William S
authors.initials: WS
authors.lastname: Linn
authors.forename: Sheryl L
authors.initials: SL
authors.lastname: Terrell
authors.forename: Kenneth W
authors.initials: KW
authors.lastname: Clark
authors.forename: Michael D
authors.initials: MD
authors.lastname: Geller
authors.forename: Karen R
authors.initials: KR
authors.lastname: Anderson
authors.forename: Wayne E
authors.initials: WE
authors.lastname: Cascio
authors.forename: Constantinos
authors.initials: C
authors.lastname: Sioutas
mesh_terms: D000328:Adult; D000397:Air Pollution / Q000009:adverse effects*; D001249:Asthma / Q000503:physiopathology*; D001273:Atmosphere Exposure Chambers; D015716:Electrocardiography, Ambulatory; D005260:Female; D006339:Heart Rate; D006801:Humans; D019570:Inhalation Exposure / Q000009:adverse effects*; D015141:Los Angeles; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D010316:Particle Size; D013147:Spirometry; D013183:Sputum / Q000166:cytology; D013383:Suburban Population; D011795:Surveys and Questionnaires
chemical_list: D010100:Oxygen