Osuga Tatsuyuki, Nakamura Kensuke, Morita Tomoya, Nisa Khoirun, Yokoyama Nozomu, Sasaki Noboru, Morishita Keitaro, Ohta Hiroshi, Takiguchi Mitsuyoshi
Am J Vet Res. 2016 Sep;77(9):952-60. doi: 10.2460/ajvr.77.9.952.
OBJECTIVE To elucidate the relationship between acute volume overload and left atrial phasic function in healthy dogs. ANIMALS 6 healthy Beagles. PROCEDURES Dogs were anesthetized. A Swan-Ganz catheter was placed to measure mean pulmonary capillary wedge pressure (PCWP). Cardiac preload was increased by IV infusion with lactated Ringer solution at 150 mL/kg/h for 90 minutes. Transthoracic echocardiography was performed before (baseline) and at 15, 30, 45, 60, 75, and 90 minutes after volume loading began. At each echocardiographic assessment point, apical 4-chamber images were recorded and analyzed to derive time-left atrial area curves. Left atrial total (for reservoir function), passive (for conduit function), and active (for booster-pump function) fractional area changes were calculated from the curves. RESULTS Volume overload resulted in a significant increase from baseline in PCWP from 15 to 90 minutes after volume loading began. All fractional area changes at 15 to 90 minutes were significantly increased from baseline. In multiple regression analysis, quadratic regression models were better fitted to the relationships between PCWP and each of the total and active fractional area changes than were linear regression models. A linear regression model was better fitted to the relationship between PCWP and passive fractional area change. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that left atrial phasic function assessed on the basis of left atrial phasic areas was enhanced during experimental cardiac volume loading in healthy dogs. The effect of volume load should be considered when evaluating left atrial phasic function by indices derived from left atrial phasic sizes.
目的 阐明健康犬急性容量超负荷与左心房阶段性功能之间的关系。动物 6 只健康的比格犬。方法 对犬实施麻醉。放置 Swan-Ganz 导管以测量平均肺毛细血管楔压（PCWP）。通过以 150 mL/kg/h 的速度静脉输注乳酸林格溶液 90 分钟来增加心脏前负荷。在容量负荷开始前（基线）以及开始后 15、30、45、60、75 和 90 分钟进行经胸超声心动图检查。在每个超声心动图评估点，记录并分析心尖四腔心图像以得出左心房面积随时间变化的曲线。根据这些曲线计算左心房总的（用于储存功能）、被动的（用于管道功能）和主动的（用于辅助泵功能）面积分数变化。结果 容量超负荷导致容量负荷开始后 15 至 90 分钟时 PCWP 较基线显著升高。15 至 90 分钟时所有的面积分数变化均较基线显著增加。在多元回归分析中，二次回归模型比线性回归模型更适合描述 PCWP 与总的和主动的面积分数变化之间的关系。线性回归模型更适合描述 PCWP 与被动面积分数变化之间的关系。结论及临床意义 结果表明，在健康犬实验性心脏容量负荷期间，基于左心房阶段性面积评估的左心房阶段性功能增强。在通过源自左心房阶段性大小的指标评估左心房阶段性功能时，应考虑容量负荷的影响。
