We found evidence that plasma levels of active VWF are an independent risk factor for first STEMI in patients from three different ethnic groups. Our findings confirm the presence of VWF abnormalities in patients with STEMI and may be used to develop new therapeutic approaches.
Background-The inability to match lung perfusion to ventilation because of a reduced cardiac output on exercise contributes to reduced exercise capacity in chronic heart failure.Objective-To quantify ventilation to perfusion matching at rest and at peak exercise in patients with chronic heart failure and relate this to haemodynamic and ventilatory variables of exercise capacity. Design-Eight men in New York Heart Association class II underwent maximal bicycle ergometry with i gas anasis. Main outcome measures-On separate days, ventilation and perfusion gamma camera imaging was performed at rest, and at 80% of previous peak exercise heart rate during bicycle ergometry. The vertical distribution of mismatch between ventilation and perfusion (V/Q) was estimated from subtracted profiles of activity (ventilation and perfusion) to derive a numerical index of global mismatch. Results-Maximal mean (SD) oxygen consumption on bicycle ergometry was 16-0 (4.5) ml min-' kg-'. There was a reduction in the global V/Q mismatch index from 23-96 (5.90) to 14-88 (7.90) units (p < 0.01) at rest and at peak exercise. Global V/Q mismatch index at peak exercise correlated negatively with maximal minute ventilation (R = -0 90, p < 0-01) and with maximal mean arterial pressure (R = -0 79, p < 0.05), although no relation was seen with maximal oxygen consumption. The reduction in global V/Q mismatch index from rest to peak exercise correlated with maximal oxygen consumption (R = 0-88, p < 0.01), and with maximal minute ventilation (R = 0-87, p < 0.01). Conclusions-During exercise in patients with chronic heart failure, there is a reduction in the global V/Q mismatch index. A lower global V/Q mismatch index at peak exercise is associated with higher maximal ventilation. The reduction in global VIQ mismatch index on exercise correlates weli with maximal exercise capacity. This may imply that the inability to perfuse adequately all regions of lung on exercise and match this to ventilation is a factor determiniing exercise capacity in chronic heart failure.(Br Heart J 1993;70:241-246)
Bronchoconstriction is seen at rest in patients with chronic heart failure, and may contribute towards exercise limitation. To investigate the effect of bronchodilator agents on exercise capacity, 10 patients (mean age 60 years, range 39-72) in New York Heart Association class II and III heart failure, underwent symptom-limited maximal exercise testing after inhalation of nebulized salbutamol (5 mg), ipratropium bromide (500 micrograms) or placebo delivered on separate days in a randomized, double-blinded study. There was an increase in forced expiratory volume in one second from pre-treatment to after nebulizer, 2.28 +/- 0.20 to 2.38 +/- 0.19 l (P < 0.05) with salbutamol, and 2.27 +/- 0.21 to 2.37 +/- 0.21 l (P < 0.05) with ipratropium bromide. There was an increase in maximal oxygen consumption after salbutamol 17.9 +/- 1.3 ml.kg-1.min-1 (P < 0.05) and ipratropium bromide 17.0 +/- 1.4 ml.kg-1.min-1 (P < 0.05), compared with placebo 16.3 +/- 1.4 ml.kg-1.min +/- 1. Peak minute ventilation during exercise also increased after salbutamol 52.8 +/- 4.5 l.min-1 (P < 0.05), compared with placebo 46.1 +/- 3.1 l.min-1. The small but significant increase in exercise capacity in chronic heart failure following bronchodilator agents implies that a degree of bronchoconstriction is present in these patients and contributes to exercise limitation.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.