Đang chuẩn bị liên kết để tải về tài liệu:
Cardiology Core Curriculum - part 7

Không đóng trình duyệt đến khi xuất hiện nút TẢI XUỐNG Tải xuống

Thời gian phẫu thuật hẹp động mạch chủ. Thời gian tối ưu thay thế van cho bệnh nhân bị hẹp động mạch chủ phụ thuộc vào mức độ nghiêm trọng của tổn thương cơ bản và tình trạng các triệu chứng của bệnh nhân huyết động học. AVA, van động mạch chủ; CHF, sung huyết suy tim | Cardiology Core Curriculum Clinical detection Symptom status Treatment Assessment of severity Figure 12.4 Timing of surgery for aortic stenosis. The optimal timing of valve replacement for patients with aortic stenosis depends on the hemodynamic severity of the underlying lesion and the symptomatic status of the patient. AVA aortic valve area CHF congestive heart failure CXR chest x ray ECG electrocardiogram echo Doppler echocardiogram PE physical examination Mitral regurgitation Mitral regurgitation has many causes. Irrespective of etiology a portion of left ventricular output is ejected into the low pressure left atrium. Cardiac output may be maintained at rest but is reduced during exercise resulting in fatigue during exertion. The optimal timing of surgery in mitral regurgitation is complicated and depends on several factors such as the etiology acuity and severity of regurgitation degree of functional impairment and left ventricular ejection fraction. Etiology and natural history Normal functioning of the mitral valve depends on the coordinated action of each of its components including the leaflets annulus chordae papillary muscles and underlying left ventricular myocardium. Disruption of normal function of any of these components may lead to mitral regurgitation Box 12.1 . In myxomatous degeneration the mitral leaflet tissue or chordae may be redundant preventing precise coaptation of leaflet edges. In rheumatic deformity of the mitral valve excessive scarring may 372 Valvular disease and infective endocarditis shorten the leaflets or chordae allowing a potential orifice to form during systole. During marked left ventricular dilatation the geometric orientation of the papillary muscles may pull the leaflet edges away from one another during systole causing secondary mitral regurgitation. Box 12.1 Causes of mitral regurgitation Ischemic heart disease with papillary muscle dysfunction Myxomatous degeneration prolapse Marfan s syndrome Infective endocarditis .