Lack of effect of nitrogen dioxide exposure on heart rate variability in patients with stable coronary heart disease and impaired left ventricular systolic function.
OBJECTIVE
Epidemiological studies of air pollution on cardiovascular health show associations of cardiac mortality and admissions with exposure to nitrogen dioxide (NO(2)) at low concentrations. These associations could be causal or NO(2) could be acting as a surrogate measure for another air pollutant, most likely ultrafine particles. No studies of cardiac susceptibility to acute exposure to NO(2) have been undertaken.


METHODS
Randomised controlled exposures to NO(2) (400 ppb for 1 h) and air in subjects with coronary heart disease and impaired left ventricular systolic function not taking β adrenoceptor blocking drugs.


RESULTS
There were no significant changes in heart rate, blood pressure, leucocyte coping capacity or any heart rate variability measure following NO(2) exposure compared with air.


CONCLUSIONS
These findings suggest that NO(2) does not affect heart rate variability at these concentrations (which are high for urban background levels) and in the absence of other pollutants. While a synergistic effect has not been ruled out, these data lend support to the idea that the epidemiological data associating cardiac outcomes with NO(2) are more likely due to an associated pollutant rather than NO(2) itself.
Department of Environmental and Occupational Medicine, University of Aberdeen, Aberdeen, UK.
Alison
A
Scaife
Justin
J
Barclay
Graham S
GS
Hillis
Janaki
J
Srinivasan
David W
DW
Macdonald
John A S
JA
Ross
Jon G
JG
Ayres
D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use; D000368:Aged; D000388:Air; D000393:Air Pollutants / Q000494:pharmacology*; D000397:Air Pollution; D003327:Coronary Disease / Q000503:physiopathology; D004781:Environmental Exposure; D005260:Female; D006321:Heart / Q000187:drug effects / Q000502:physiology; D006339:Heart Rate / Q000187:drug effects* / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009585:Nitrogen Dioxide / Q000494:pharmacology*; D010316:Particle Size; D052638:Particulate Matter / Q000494:pharmacology*; D016037:Single-Blind Method; D013599:Systole; D016277:Ventricular Function, Left
D000319:Adrenergic beta-Antagonists; D000393:Air Pollutants; D052638:Particulate Matter; D009585:Nitrogen Dioxide