Broughton A, Korner P I
Am J Physiol. 1986 Dec;251(6 Pt 2):H1260-6. doi: 10.1152/ajpheart.1986.251.6.H1260.
We compared open-chest left ventricular (LV) pump performance after autonomic blockade under controlled loading conditions in normal dogs and in dogs where chronic renovascular hypertension had produced moderate concentric LV hypertrophy (LVH). Mean LV pressure (MLVP) provided a measure of ventricular load independent of vascular properties. We found an inverse relationship between MLVP and cardiac index (CI) in both groups when peripheral resistance was altered at constant left atrial pressure. However, CI declined significantly less in LVH hearts as MLVP was increased. The slope of the linear MLVP-CI plot (LV source resistance) was 1.91 times the value observed in normal dogs. LVH hearts developed more steady-flow external power than their normal counterparts, and the power optimum was reached at a much higher mean arterial pressure. Isovolumic maximum rate of LVP rise was 1.28 times higher in LVH than normal dogs (P less than 0.01) in proportion to the increase in wall thickness. Our results suggest that additional muscle with normal contractile properties and greater emptying due to the increased wall-to-lumen ratio accounted for the increased pump performance in LVH.
我们比较了正常犬以及因慢性肾血管性高血压导致中度同心性左心室肥厚（LVH）的犬在自主神经阻滞及受控负荷条件下的开胸左心室（LV）泵功能。平均左心室压力（MLVP）可提供一种独立于血管特性的心室负荷测量方法。当在恒定左心房压力下改变外周阻力时，我们发现两组中MLVP与心脏指数（CI）之间均呈负相关。然而，随着MLVP升高，LVH心脏中CI的下降幅度明显较小。线性MLVP-CI图的斜率（LV源阻力）是正常犬中观察值的1.91倍。LVH心脏比正常心脏产生了更稳定的外部血流动力，并且在更高的平均动脉压下达到动力最佳状态。与壁厚增加成比例，LVH犬的等容LVP最大上升速率比正常犬高1.28倍（P小于0.01）。我们的结果表明，具有正常收缩特性的额外心肌以及因壁腔比增加而导致的更强排空能力，是LVH中泵功能增强的原因。
