tailieunhanh - Cardiovascular Imaging A handbook for clinical practice - Part 7

Hẹp tĩnh mạch phổi rung tâm nhĩ là một loạn nhịp tim phổ biến được tìm thấy trong 1% của người lớn tuổi hơn 60 năm và đó là một dấu hiệu của đột quỵ. Cắt bỏ tĩnh mạch phổi cung cấp tiềm năng để chữa trị bệnh nhân bị rung tâm nhĩ | 172 Chapter 14 lying supine and standing upright. This maneuver demonstrates a large right-to-left shunt through a PFO while the patient is in an upright position and no significant shunt while in a recumbent position. Uncommon cardiac conditions associated with dyspnea Pulmonary vein stenosis Atrial fibrillation is a common arrhythmia that is found in 1 of persons older than 60 years and it is a predictor of stroke. Pulmonary vein ablation offers the potential to cure patients with atrial fibrillation. However the risk of significant pulmonary vein stenosis or occlusion after radiofrequency catheter ablation of refractory atrial fibrillation has been reported. The clinical manifestations of pulmonary vein stenosis are variable including chest pain cough hemoptysis recurrent lung infection pulmonary hypertension and dyspnea. In patients with dyspnea and a history of radiofrequency catheter ablation for atrial fibrillation pulmonary vein stenosis should be suspected. In echocardiographic examination two-dimensional echocardiography alone is not sufficient to detect this anomaly. Color Doppler imaging can easily demonstrate turbulent flow from the entry point of the pulmonary vein and thus suggest obstruction. Transesophageal echocardiography is well suited to examination of the pulmonary veins and to diagnosis of pulmonary venous obstruction. Frequency aliasing observed by transthoracic color Doppler imaging is also an important clue in the diagnosis of pulmonary vein stenosis. Doppler echocardiography can be used in the quantitative analysis of severity of functional abnormality. However in some instances of increased angle to flow the actual pressure gradient produced by the obstruction may be underestimated. Constrictive pericarditis Constrictive pericarditis is a form of diastolic heart failure as a fibrotic thickened and adherent pericardium restricts diastolic filling of the heart. The symmetrical constricting effect of the pericardium results in elevation and