Munakata K, Shirato K, Ishikawa K, Sakuma M, Kanazawa M, Haneda T, Takishima T
The First Department of Internal Medicine, Tohoku University School of Medicine, Sendai, Japan.
Tohoku J Exp Med. 1995 Oct;177(2):93-106. doi: 10.1620/tjem.177.93.
To evaluate the role of the right ventricular (RV) free wall in cardiac function, RV and left ventricular (LV) wall segment lengths were measured by ultrasonic crystals in 10 open chest dogs with the pericardium preserved. Right coronary artery (RCA) was perfused separately by own blood and the flow was reduced stepwise until active shortening (delta L) of the RV segment disappeared or RCA flow became zero (Ischemia). The experiment was repeated with and without pulmonary stenosis (PS). At Ischemia, RV and LV systolic pressures decreased. RV end-diastolic length increased and RV delta L decreased. LV end-diastolic length and LV delta L were reduced. LV stroke volume concurrently fell. These changes became more prominent with PS. The critical level of RCA flow, at which RV delta L began to change, was higher with PS (5.27 +/- 2.85 ml/min, mean +/- S.D.) than without PS (1.44 +/- 1.16, p < 0.01). Based on the relationships between RV delta L and percent changes in RV developed pressure and stroke volume, the degree of the decreases in RV developed pressure and stroke volume at RV delta L of zero were estimated to be about 20%. These results indicate that the RV free wall partly contributes to maintaining the RV function, especially during RV pressure overload.
为评估右心室（RV）游离壁在心脏功能中的作用，在10只开胸且心包完整的犬中，用超声晶体测量右心室和左心室（LV）壁节段长度。通过自身血液分别灌注右冠状动脉（RCA），并逐步减少血流量，直至右心室节段的主动缩短（ΔL）消失或RCA血流变为零（缺血）。在有和没有肺动脉狭窄（PS）的情况下重复该实验。在缺血时，右心室和左心室收缩压降低。右心室舒张末期长度增加，右心室ΔL降低。左心室舒张末期长度和左心室ΔL减小。左心室每搏输出量同时下降。这些变化在有肺动脉狭窄时更为明显。右心室ΔL开始变化时的右冠状动脉血流临界水平，有肺动脉狭窄时（5.27±2.85 ml/min，平均值±标准差）高于无肺动脉狭窄时（1.44±1.16，p<0.01）。根据右心室ΔL与右心室舒张期压力和每搏输出量变化百分比之间的关系，估计右心室ΔL为零时右心室舒张期压力和每搏输出量的降低程度约为20%。这些结果表明，右心室游离壁部分有助于维持右心室功能，尤其是在右心室压力过载时。
