Breath Isoprene in Patients with Heart Failure

BACKGROUND: Chronic heart failure (CHF) is characterised by increased vascular resistance. This increased after load on the left ventricle contributes to the vicious cycle that leads to progression of myocardial failure, multiple organ failure and death. There is evidence for increased oxidative stress in heart failure, which will influence the myocardium but also peripheral vasculature endothelium. AIMS: The aim of the present study was to examine the production of isoprene, reputed to reflect oxidative stress, in patients with CHF compared to control subjects. METHODS: Twelve patients with CHF and thirty-one healthy control subjects free from heart disease were studied. Breath was collected via a two-way non-re-breathing valve into a 60-l gas collection bag. A sample of ambient air was collected at the same time. A measured aliquot of patient breath and ambient air (approx. 1.5 l) was adsorbed onto a gas adsorption tube packed with poropak-Q. Isoprene was measured using GC/MS and the production rate calculated. All samples of breath were collected at 10.00 h after subjects had been sitting at rest for 15 min. RESULTS: Breath isoprene production in subjects with CHF was significantly reduced compared to controls 83(23) vs. 168(20) pmol min(-1) kg(-1). CONCLUSION: Breath isoprene does not directly reflect oxidative stress in CHF.