Gold F L, Bache R J
Cardiovasc Res. 1982 Aug;16(8):467-72. doi: 10.1093/cvr/16.8.467.
This study tested the hypothesis that an acute increase in right ventricular pressure would result in selective impedance of blood flow into the right ventricular subendocardium (ENDO) similar to that seen normally in the left ventricle. Since tachycardia (reduces diastolic time) and vasomotor paralysis will reveal impedence to blood flow by a decrease in ENDO to subepicardial (EPI) myocardial blood flow (MBF) ratio, MBF was measured with microspheres in eight awake dogs during rapid pacing at 176 +/- 2 beats . min-1 (mean +/- SE) after acute pulmonary artery constriction (PAC) before and during adenosine (A) infusion (1.00 mg . kg-1 . min-1). AP was held constant by aortic constriction. During control pacing the ENDO/EPI ratios were 1.38 +/- 0.08 and 1.46 +/- 0.12 in the RV and LV, respectively. During adenosine infusion the ENDO/EPI decreased to 0.85 +/- 0.08 (P less than 0.05) in the LV but did not change in the RV (1.17 +/- 0.10). During PAC and pacing alone the RV ENDO/EPI was 1.24 +/- 0.05 (NS vs control), but during adenosine fell to 0.88 +/- 0.07 (P less than 0.05). Transmural blood flow to the interventricular septum (IVS) was also affected by increased RV pressure. During control the ratio of blood flow to the left and right side (LV/RV) of the IVS was 1.32 +/- 0.12. PAC alone caused a redistribution of MBF toward the right side and the LV/RV fell to 0.66 +/- 0.06 (P less than 0.05). During PAC and adenosine, however the LV/RV rose to 1.38 +/- 0.08. These data demonstrate that increased RV systolic pressure produces systolic impedance to blood flow to the right ventricular ENDO and the right side of the interventricular septum.
右心室压力的急性升高会导致血流选择性地受阻进入右心室心内膜下层（ENDO），类似于正常情况下左心室所见到的情况。由于心动过速（缩短舒张期）和血管运动麻痹会通过降低心内膜下层与心外膜下层（EPI）心肌血流（MBF）比值来揭示血流受阻情况，因此在8只清醒犬急性肺动脉缩窄（PAC）后，于腺苷（A）输注（1.00 mg·kg-1·min-1）前和期间，以176±2次·min-1（平均值±标准误）的频率快速起搏时，用微球测量MBF。通过主动脉缩窄使动脉压保持恒定。在对照起搏期间，右心室和左心室的ENDO/EPI比值分别为1.38±0.08和1.46±0.12。在腺苷输注期间，左心室的ENDO/EPI降至0.85±0.08（P<0.05），而右心室未发生变化（1.17±0.10）。在单独进行PAC和起搏期间，右心室ENDO/EPI为1.24±0.05（与对照相比无显著差异），但在腺苷输注期间降至0.88±0.07（P<0.05）。右心室压力升高也影响了跨室间隔（IVS）的透壁血流。在对照期间，IVS左侧和右侧血流比值（LV/RV）为1.32±0.12。单独进行PAC导致MBF重新分布至右侧，LV/RV降至0.66±0.06（P<0.05）。然而，在PAC和腺苷输注期间，LV/RV升至1.38±0.08。这些数据表明，右心室收缩压升高会对血流进入右心室心内膜下层和室间隔右侧产生收缩期阻力。
