醫學五：80題 ( 包括外科,骨科,泌尿科等科目及其相關臨床實例與醫學倫理 )題庫下載題庫

Uptodate

Chronic pulmonary regurgitation — Intracardiac repair with a transannular RVOT patch results in obligate chronic severe pulmonary regurgitation. Insufficiency may also occur in patients who have monocusp valves placed at the time of initial repair or who have a valved conduit from the RV to the pulmonary artery (PA), as these valves become progressively incompetent over time. The degree of insufficiency may vary depending on surgical approach and on the presence or absence of associated PA stenosis. In the setting of long-standing severe pulmonary regurgitation, the RV enlarges due to increased workload [33,34]. This may be associated with increasing tricuspid insufficiency, further contributing to RV enlargement.

Right ventricular enlargement and function — Patients with RV enlargement and with normal RV function are asymptomatic. However, they are at risk for the evolution of RV dysfunction, associated with decreased exercise tolerance, right heart failure, and arrhythmias (ie, VT, atrial flutter, and atrial fibrillation). The decline in RV function can also lead to left ventricular (LV) dysfunction due to septal shift and ventricular/ventricular interaction [33,35,36].

Pulmonary valve replacement and right ventricular function — Pulmonary valve replacement (PVR) may be necessary to restore pulmonary valve competence and improve RV function [37-41]. Although optimal timing of PVR remains uncertain, this option should be considered in symptomatic patients as well as in those with moderate or severe RV volume overload, RV dysfunction, tricuspid valve regurgitation, and clinical arrhythmias attributable to the right heart enlargement/dysfunction from pulmonary valve regurgitation. Ideally, PVR should occur before severe RV dysfunction develops.