Department of Surgical and Perioperative Sciences, Anesthesiology and Intensive Care Medicine, Umeå University, 901 85, Umeå, Sweden.
Department of Surgical and Perioperative Sciences, Clinical Physiology, Umeå University, Umeå, Sweden.
Cardiovasc Ultrasound. 2022 Mar 30;20(1):8. doi: 10.1186/s12947-022-00278-1.
In order to assess left atrial contractile function in disturbed circulatory conditions, it is necessary to have a clear understanding of how it behaves in a normal resting state with changes in loading conditions. However, currently the understanding of this relationship is incomplete. We hypothesize that in healthy individuals, left atrial contraction strain and its peak strain rate are increased or decreased by increasing or decreasing preload, respectively.
Controlled maneuvers used to change preload included continuous positive airway pressure by mask (CPAP 20 cmHO) for preload decrease, and passive leg raise (15 degrees angle) for preload increase. Cardiac ultrasound 4-chamber views of the left atria and left ventricle were acquired at baseline and during maneuver. Acquired images were post processed and analyzed offline. Comparisons were made using paired t-test and means with 95% confidence interval.
There were 38 participants, complete results were obtained from 23 in the CPAP maneuver and 27 in the passive leg raise maneuver. For the CPAP group, left atrial contraction strain was 11.6% (10.1 to 13.1) at baseline and 12.8% (11.0 to 14.6) during the maneuver (p = 0.16). Left atrial contraction peak strain rate was - 1.7 s (- 1.8 to - 1.5) at baseline and - 1.8 s (- 2.0 to - 1.6) during the maneuver (p = 0.29). For the passive leg raise-group, left atrial contraction strain was 10.1% (9.0 to 11.2) at baseline and 10.8% (9.4 to 12.3) during the maneuver (p = 0.28). Left atrial contraction peak strain rate was - 1.5 s (- 1.6 to - 1.4) at baseline and - 1.6 s (- 1.8 to - 1.5) during the maneuver (p = 0.29). Left atrial area, an indicator of preload, increased significantly during passive leg raise and decreased during CPAP.
In healthy individuals, left atrial contraction strain and its peak strain rate seem to be preload-independent.
The study was 2018-02-19 registered at clinicaltrials.gov ( NCT03436030 ).
为了评估循环紊乱状态下的左心房收缩功能，有必要清楚地了解在负荷条件变化的情况下，左心房在正常静息状态下的表现。然而，目前人们对这种关系的认识并不完整。我们假设在健康个体中，通过增加或降低前负荷分别增加或降低左心房收缩应变及其峰值应变率。
用于改变前负荷的控制操作包括通过面罩（CPAP20cmHO）进行前负荷降低，以及被动腿抬高（15 度角）进行前负荷增加。在基线和操作期间获取左心房和左心室的心脏超声 4 腔视图。获取的图像在线下进行后处理和分析。使用配对 t 检验和均值进行比较，并带有 95%置信区间。
共有 38 名参与者，CPAP 操作中 23 名参与者和被动腿抬高操作中 27 名参与者完成了完整的结果。对于 CPAP 组，左心房收缩应变在基线时为 11.6%（10.1 至 13.1），在操作时为 12.8%（11.0 至 14.6）（p=0.16）。左心房收缩峰值应变率在基线时为-1.7s（-1.8 至-1.5），在操作时为-1.8s（-2.0 至-1.6）（p=0.29）。对于被动腿抬高组，左心房收缩应变在基线时为 10.1%（9.0 至 11.2），在操作时为 10.8%（9.4 至 12.3）（p=0.28）。左心房收缩峰值应变率在基线时为-1.5s（-1.6 至-1.4），在操作时为-1.6s（-1.8 至-1.5）（p=0.29）。左心房面积，前负荷的一个指标，在被动腿抬高时显著增加，而在 CPAP 时减少。
在健康个体中，左心房收缩应变及其峰值应变率似乎与前负荷无关。
该研究于 2018 年 2 月 19 日在 clinicaltrials.gov（NCT03436030）注册。
