Lack of effect of nitrogen dioxide exposure on heart rate variability in patients with stable coronary heart disease and impaired left ventricular systolic function

This randomized, single blind, placebo-controlled study evaluated the effect nitrogen dioxide exposure on cardiac rate, cardiac rhythm, heart rate variability, and leucocyte coping capacity in 18 patients with coronary heart disease and left ventricular systolic dysfunction who were not taking β-blockers. Lung function testing (FEV1 and FVC) was undertaken using a Vitalograph Micro spirometer, with patients with airflow obstruction unable to participate in the study.