Patients being treated for heart attacks involving narrowed arteries and clots that reduce blood flow to the heart are often given overdoses of powerful blood - thinning drugs in the emergency room , increasing their risk of serious bleeding , a study has found 一项研究发现，因心脏病发作（包括会减少流向心脏的血液的动脉狭窄及血液凝固）而接受治疗的患者在急诊室常被给予过量的强有力的血液稀释剂，增加了他们严重出血的风险。
Other mechanisms become involved when hypertension due to an identifiable cause ( eg , catecholamine release from a pheochromocytoma , renin and angiotensin from renal artery stenosis , aldosterone from an adrenal cortical adenoma ) has existed for some time 当因某些易于确定的原因所引起的高血压存在一段时间后，如嗜铬细胞瘤释放的儿茶酚胺、肾动脉狭窄所产生的肾素和血管紧张素、肾上腺皮质腺瘤分泌的醛固酮等，其他机制也会参与高血压病的形成。
One cardiac cycle is divided into 50 parts in the transient analysis to accurately simulate the continuous pulsatile blood flow in the coronary artery , the hemodynamic parameters of the atherosclerotic and the controlled models at each of the 50 moments were computed in accordance with the physiological condition 这些计算包括：脉动流情况下的非狭窄和狭窄不对称性对狭窄流场的影响，分岔角度变化时动脉狭窄和非狭窄的各种血流动力学参数的计算模拟。
With the improvement of the living standard in our country , the incidence of arterous stenostic and dilative diseases are increasing steadily . in the recently forty years , with the research and development of vascular prostheses , the replacement and bypass of arteries with textile vascular prostheses has proved very successful in clinic operation 在我国，随着人民生活水平的提高，动脉狭窄性疾病和扩张性病变的发病率也不断上升，近四十多年来，由于人造血管的出现和发展，用外科手术治疗血管疾患，已成为一种常规临床手术。
Objectives : the aim of the present study was to evaluate whether patients with paroxysmal atrial fibrillation ( af ) without symptoms of cerebral ischemia or significant carotid stenosis have reduced blood flow through the middle cerebral arteries ( mcas ) , as well as to assess differences between blood flow through the mcas during af and after cardioversion 目的：本研究目的在于评价没有脑缺血症状或没有明显颈动脉狭窄的阵发性心房纤颤患者是否存在大脑中动脉血流的下降，而且对房颤发生期和心脏复律期大脑中动脉血流的差异进行比较。
