Louie E K, Lin S S, Reynertson S I, Brundage B H, Levitsky S, Rich S
Division of Cardiology, Loyola University Medical Center, Maywood, Ill. 60153, USA.
Circulation. 1995 Aug 15;92(4):819-24. doi: 10.1161/01.cir.92.4.819.
Left ventricular ejection fraction has been reported to be depressed in patients with right ventricular volume overload (RVVO) due to Ebstein's anomaly and uncomplicated atrial septal defect, whereas it is usually preserved in right ventricular pressure overload (RVPO) due to congenital pulmonic stenosis. In the present study, we examined the hypothesis that the differential timing of active displacement of the ventricular septum into the left ventricle in RVPO (end systole) and RVVO (end diastole) results in opposite effects of RVPO and RVVO on left ventricular ejection fraction.
Ten patients with severe tricuspid regurgitation after tricuspid valve resection for endocarditis and 10 patients with primary pulmonary hypertension were studied as models of isolated RVVO and RVPO, respectively. Left ventricular ejection fraction, end-diastolic volume, and regional systolic shortening were measured with the use of echocardiographic techniques in these 20 patients and 10 healthy control subjects. In RVPO, despite marked underfilling of the left ventricle relative to the healthy control subjects (end-diastolic volume, 48 +/- 26 versus 77 +/- 20 mL; P < .02), left ventricular ejection fraction was similar to that of the control subjects (56 +/- 5% versus 60 +/- 4%; P = .07) and only 1 of 10 RVPO patients had an ejection fraction of less than 50%. In contrast, in RVVO the left ventricle was volume replete (end-diastolic volume, 84 +/- 26 versus 77 +/- 20 mL; P = NS), but left ventricular ejection fraction was significantly depressed (51 +/- 4% versus 60 +/- 4%, P < .001) compared with the control subjects, and 4 of 10 RVVO patients had an ejection fraction of less than 50%. Analysis of systolic fractional shortening along two perpendicular short-axis diameters and the mutually orthogonal long axis demonstrated isolated augmentation of fractional shortening in the ventricular septal-to-posterolateral free wall dimension in RVPO (47.4 +/- 13.7% versus 34.2 +/- 13.1%, P < .05) and isolated depression of fractional shortening along that same dimension in RVVO (13.7 +/- 11.8% versus 34.2 +/- 13.1%, P < .001) compared with the control subjects.
End-systolic leftward ventricular septal shift in RVPO results in isolated augmentation of systolic shortening in the septal-to-free wall dimension, whereas end-diastolic leftward ventricular septal shift in RVVO results in isolated reduction in systolic shortening in the septal-to-free wall dimension. As a result, despite relative underfilling of the left ventricle in RVPO, resting left ventricular ejection fraction is preserved, whereas ejection fraction is depressed for the volume-replete left ventricle of patients with RVVO.
据报道，因埃布斯坦畸形和单纯性房间隔缺损导致右心室容量超负荷（RVVO）的患者左心室射血分数降低，而因先天性肺动脉狭窄导致右心室压力超负荷（RVPO）的患者左心室射血分数通常保持正常。在本研究中，我们检验了这样一个假设，即RVPO（收缩末期）和RVVO（舒张末期）时室间隔主动向左心室移位的不同时间导致RVPO和RVVO对左心室射血分数产生相反的影响。
分别将10例因感染性心内膜炎行三尖瓣切除术后出现严重三尖瓣反流的患者和10例原发性肺动脉高压患者作为孤立性RVVO和RVPO的模型进行研究。使用超声心动图技术对这20例患者和10例健康对照者测量左心室射血分数、舒张末期容积和局部收缩期缩短率。在RVPO患者中，尽管相对于健康对照者左心室明显充盈不足（舒张末期容积，48±26 ml对77±20 ml；P<0.02），但其左心室射血分数与对照者相似（56±5%对60±4%；P = 0.07），10例RVPO患者中只有1例射血分数低于50%。相比之下，在RVVO患者中左心室容量充足（舒张末期容积，84±26 ml对77±20 ml；P = 无显著性差异），但与对照者相比左心室射血分数显著降低（51±4%对60±4%，P<0.001），10例RVVO患者中有4例射血分数低于50%。沿两条相互垂直的短轴直径和相互正交的长轴分析收缩期缩短分数，结果显示，与对照者相比，RVPO患者室间隔至后外侧游离壁方向的缩短分数单独增加（47.4±13.7%对34.2±13.1%，P<0.05），而RVVO患者沿同一方向的缩短分数单独降低（13.7±11.8%对34.2±13.1%，P<0.001）。
RVPO时收缩末期室间隔向左心室移位导致室间隔至游离壁方向的收缩期缩短单独增加，而RVVO时舒张末期室间隔向左心室移位导致室间隔至游离壁方向的收缩期缩短单独减少。因此，尽管RVPO患者左心室相对充盈不足，但其静息左心室射血分数保持正常，而RVVO患者左心室容量充足时射血分数降低。
