Neal G. Uren

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BACKGROUND We assessed the relation between the severity of stenosis in a coronary artery and the degree of impairment of myocardial blood flow. Studies in laboratory animals have shown that as the degree of coronary-artery stenosis increases, the maximal coronary flow measured after maximal vasodilation progressively decreases, with a concomitant decrease(More)
BACKGROUND The use of non-invasive imaging to identify ruptured or high-risk coronary atherosclerotic plaques would represent a major clinical advance for prevention and treatment of coronary artery disease. We used combined PET and CT to identify ruptured and high-risk atherosclerotic plaques using the radioactive tracers (18)F-sodium fluoride ((18)F-NaF)(More)
BACKGROUND The ability of the coronary vascular bed to dilate and thus increase blood flow to the myocardium may be impaired in coronary artery disease, even in regions of myocardium supplied by an angiographically normal coronary artery. If this kind of vasomotor dysfunction was present or accentuated after acute myocardial infarction, it might influence(More)
BACKGROUND The appropriate treatment for patients in whom reperfusion fails to occur after thrombolytic therapy for acute myocardial infarction remains unclear. There are few data comparing emergency percutaneous coronary intervention (rescue PCI) with conservative care in such patients, and none comparing rescue PCI with repeated thrombolysis. METHODS We(More)
BACKGROUND It remains unclear whether myocardial ischemia due to coronary microvascular dysfunction is the cause of chest pain in syndrome X (chest pain, ischemic-like stress ECG despite angiographically normal coronary arteries). To assess the function of the coronary microcirculation and its relation to pain perception, we measured myocardial blood flow(More)
OBJECTIVES This study was conducted to determine the myocardial beta-adrenoceptor density as a marker of sympathetic function in patients with hypertrophic cardiomyopathy and normal control subjects. BACKGROUND Although some cases of hypertrophic cardiomyopathy are familial with an autosomal dominant pattern of inheritance, there remains a substantial(More)
BACKGROUND NG-Monomethyl-L-arginine (L-NMMA), a specific inhibitor of nitric oxide synthesis, was used to determine the effects of inhibition of nitric oxide synthesis in the human coronary circulation. METHODS AND RESULTS Twelve patients (mean age, 52 +/- 2 years) with normal epicardial coronary arteries were studied. The surface ECG, systemic blood(More)
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(More)
OBJECTIVES The aim of this study was to investigate coronary vasodilator reserve and metabolism in myocardium subtended by angiographically normal arteries remote from ischemia. BACKGROUND After infarction, structural and functional changes occur in remote myocardium often subtended by normal arteries. Whether changes occur in regions remote from ischemic(More)
UNLABELLED Myocardial perfusion reserve (hyperemic divided by basal myocardial blood flow) describes vasodilator responsiveness of coronary-resistive vessels. The effect of aging and gender on myocardial perfusion reserve remains controversial. METHODS We studied 56 normal volunteers (21 women, 35 men; aged 50 +/- 20 yr, range 21-86 yr) with 15O-water PET(More)