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- Title
Controlled Exposure Study of Air Pollution and T-Wave Alternans in Volunteers without Cardiovascular Disease.
- 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
- Abstract
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 particulate 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 (TWAMax) 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.
- Subjects
ONTARIO; HEART conduction system; AIR pollution; ANALYSIS of variance; BLOOD pressure; ELECTROCARDIOGRAPHY; HEART beat; OZONE; RESEARCH funding; STATISTICAL sampling; PARTICULATE matter; BLIND experiment; DATA analysis software; DESCRIPTIVE statistics; PHYSIOLOGY
- Publication
Environmental Health Perspectives, 2012, Vol 120, Issue 8, p1157
- ISSN
0091-6765
- Publication type
Article
- DOI
10.1289/ehp.1104171