Cardiovascular effects of ozone exposure in human volunteers

We hypothesized that ozone (O-3) exposure acutely affects cardiovascular hemodynamics in humans and, in particular, in subjects with essential hypertension. We studied 10 nonmedicated hypertensive and six healthy male adults. Each subject, after catheterization of the right heart and a radial artery, was exposed in an environmentally controlled chamber to filtered air (FA) on one day and to 0.3 ppm O-3 On the following day for 3 h with intermittent exercise. Relative to FA exposure, O-3 exposure induced no statistically significant changes in cardiac index, ventricular performance, pulmonary artery pressure, pulmonary and systemic vascular resistances, EGG, serum cardiac enzymes, plasma catecholamines and atrial natriuretic factor, and Sa(O2). The overall results did not indicate major acute cardiovascular effects of O-3 in either the hypertensive or the control subjects. However, mean preexposure to postexposure changes were significantly (p < 0.02) larger with O-3 than with FA for rate-pressure product (1,353 beats/min/mm Hg) and for heart rate (8 beats/min); these responses were not significantly different between the hypertensive and the control subjects. Significant O-3 effects were also observed for mean FEV1 (-6%), and AaPO(2) (> 10 mm Hg increase), which were not significantly different between the two groups. These results suggest that O-3 exposure can increase myocardial work and impair pulmonary gas exchange to a degree that might be clinically important in persons with significant preexisting cardiovascular impairment, with or without concomitant lung disease.