01857nas a2200205   4500000000100000008004100001100001400042700001800056700001700074700001200091700001500103700001800118700001300136245016900149250001500318300001100333490000700344520125400351020004601605       2012                            d1 aScaife A.1 aSrinivasan J.1 aMacdonald D.1 aRoss J.1 aBarclay J.1 aHillis Graham1 aAyres J.00aLack of effect of nitrogen dioxide exposure on heart rate variability in patients with stable coronary heart disease and impaired left ventricular systolic function  a2012/06/14  a587-910 v693 a<p>
Objectives 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 beta 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. Conclusion 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.
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