Controlled Exposure Study of Air Pollution and T-Wave Alternans in Volunteers without Cardiovascular Disease

• Published in: Environmental health perspectives Vol. 120; no. 8; pp. 1157 - 1161
• Main Authors: Kusha, Marjan, Masse, Stephane, Farid, Talha, Urch, Bruce, Silverman, Frances, Brook, Robert D., Gold, Diane R., Mangat, Iqwal, Speck, Mary, Nair, Krishnakumar, Poku, Kwaku, Meyer, Chris, Mittleman, Murray A., Wellenius, Gregory A., Nanthakumar, Kumaraswamy
• Format: Journal Article
• Language: English
• Published: Research Triangle Park, NC National Institute of Environmental Health Sciences 01.08.2012; US Department of Health and Human Services
• Subjects: Adolescent; Adult; Air; Air pollutants; Air Pollution; Alternan; Biological and medical sciences; Cardiac dysrhythmias; Cardiology. Vascular system; Cardiovascular Diseases; Disease control; Dysrhythmias; Electrocardiography; Elevated; Environment. Living conditions; Environmental Exposure; Environmental health; Environmental pollutants toxicology; Exposure; Exposure chambers; Female; Health aspects; Heart; Heart rate; Human; Humans; Male; Medical sciences; Ozone; Particulate matter; Pollutants; Pollution studies; Public health. Hygiene; Public health. Hygiene-occupational medicine; Reference Values; Rest; Toxicology; Variance analysis; Volunteers; Young Adult; United States; Human; Arrhythmia; Volunteer; controlled exposure; Ozone; Cardiovascular disease; Exposure; T-wave alternans; Suspended particle; particulate matter; Health and environment; Heart disease; Air pollution; Public health
• ISSN: 0091-6765; 1552-9924; 1552-9924
• DOI: 10.1289/ehp.1104171

Background: Epidemiological studies have assessed T-wave alternans (TWA) as a possible mechanism of cardiac arrhythmias related to air pollution in high-risk subjects and have reported associations with increased TWA magnitude. Objective: In this controlled human exposure study, we assessed the impact of exposure to concentrated ambient paniculate matter (CAP) and ozone (O₃) on T-wave alternans in resting volunteers without preexisting cardiovascular disease. Methods: Seventeen participants without preexisting cardiovascular disease were randomized to filtered air (FA), CAP (150 μg/m³), O₃ (120 ppb), or combined CAP + O₃ exposures for 2 hr. Continuous electrocardiograms (ECGs) were recorded at rest and T-wave alternans (TWA) was computed by modified moving average analysis with QRS alignment for the artifact-free intervals of 20 beats along the V2 and V5 leads. Exposure-induced changes in the highest TWA magnitude (TWA Max) were estimated for the first and last 5 min of each exposure (TWAMax _ Early and TWAMax_ Late respectively). ΔTWAMax (Late— Early) were compared among exposure groups using analysis of variance. Results: Mean ± SD values for ΔTWAMax were -2.1 ± 0.4, -2.7 ± 1.1, -1.9 ± 1.5, and -1.2 ± 1.5 in FA, CAP, O₃, and CAP + O₃ exposure groups, respectively. No significant differences were observed between pollutant exposures and FA. Conclusion: In our study of 17 volunteers who had no preexisting cardiovascular disease, we did not observe significant changes in T-wave alternans after 2-hr exposures to CAP, O₃, or combined CAP + O₃. This finding, however, does not preclude the possibility of pollution-related effects on TWA at elevated heart rates, such as during exercise, or the possibility of delayed responses.