Electrocardiographic and respiratory responses to coal-fired power plant emissions in a rat model of acute myocardial infarction: results from the Toxicological Evaluation of Realistic Emissions of Source Aerosols Study.

BACKGROUND: Ambient particulate matter (PM) derived from coal-fired power plants may have important cardiovascular effects, but existing toxicological studies are inadequate for understanding these effects. The Toxicological Evaluation of Realistic Emissions of Source Aerosols (TERESA) study aims to evaluate the toxicity of primary and secondary PM derived from coal-fired power plants. As a part of this effort, we evaluated in susceptible animals the effect of stack emissions on cardiac electrophysiology and respiratory function under exposure conditions intended to simulate an aged plume with unneutralized acidity and secondary organic aerosols (POS exposure scenario).
METHODS: Rats with acute myocardial infarction were exposed to either stack emissions (n = 15) or filtered air (n = 14) for 5 h at a single power plant. Respiration and electrocardiograms were continuously monitored via telemetry and heart rate, heart rate variability (HRV), premature ventricular beat (PVB) frequency, electrocardiographic intervals, and respiratory intervals and volumes were evaluated. Similar experiments at another power plant were attempted but were unsuccessful.
RESULTS: POS exposure (fine particle mass = 219.1 µg/m(3); total sulfate = 172.5 µg/m(3); acidic sulfate = 132.5 µg/m(3); organic carbon = 50.9 µg/m(3)) was associated with increased PVB frequency and decreased respiratory expiratory time and end-inspiratory pause, but not with changes in heart rate, HRV, or electrocardiographic intervals. RESULTS from a second power plant were uninterpretable.
CONCLUSIONS: Short-term exposure to primary and unneutralized secondary PM formed from aged emissions from a coal-fired power plant, as simulated by the POS scenario, may be associated with increased risk of ventricular arrhythmias in susceptible animals.