Sawhney Navinder, Faddis Mitchell
Washington University School of Medicine, Cardiovascular Division, 660 South Euclid Avenue, Campus Box 8086, St. Louis, MO 63110, USA.
Curr Treat Options Cardiovasc Med. 2002 Aug;4(4):277-285. doi: 10.1007/s11936-002-0008-2.
Ventricular contraction is achieved by the coordinated electrical activation of the ventricles through the action of the cardiac conduction system. In the presence of left bundle branch block (LBBB) or interventricular conduction delay (IVCD), the ventricular contraction pattern is desynchronized and the stroke volume is reduced as a consequence. In patients with congestive heart failure (CHF) due to systolic dysfunction, the presence of LBBB or IVCD further degrades ventricular function, contributing directly to the severity of their CHF symptoms. Cardiac resynchronization therapy (CRT) through biventricular pacing relieves CHF symptoms and improves functional status in patients with medically refractory heart failure due to left ventricular systolic dysfunction and LBBB or IVCD. The benefits of CRT are due to improvement in the ventricular activation sequence, resulting in a more coordinated and efficient ventricular contraction. In addition to symptomatic benefits, available data support the hypothesis that CRT alters the natural history of CHF in patients with intraventricular conduction delay.
心室收缩是通过心脏传导系统的作用使心室进行协调性电激活来实现的。在存在左束支传导阻滞（LBBB）或室内传导延迟（IVCD）的情况下，心室收缩模式会不同步，结果导致每搏输出量减少。在因收缩功能障碍导致的充血性心力衰竭（CHF）患者中，LBBB或IVCD的存在会进一步损害心室功能，直接加重其CHF症状的严重程度。通过双心室起搏进行的心脏再同步治疗（CRT）可缓解因左心室收缩功能障碍和LBBB或IVCD导致的药物难治性心力衰竭患者的CHF症状，并改善其功能状态。CRT的益处源于心室激活顺序的改善，从而导致更协调、更有效的心室收缩。除了有症状改善的益处外，现有数据支持这样的假说，即CRT会改变存在室内传导延迟的CHF患者的CHF自然病程。
