St Francis Hospital, Research Department, State University of New York-Stony Brook, 100 Port Washington Blvd., Roslyn, NY 11576, USA.
Circ Cardiovasc Imaging. 2011 Mar;4(2):130-8. doi: 10.1161/CIRCIMAGING.110.959569. Epub 2011 Jan 24.
Left atrial (LA) size and function reflect left ventricular (LV) hemodynamics. In the present study, we developed a novel method to determine LA circulation transit time (LATT) by MRI and demonstrated its close association with LV filling pressure.
All subjects were prospectively recruited and underwent contrast-enhanced MR dynamic imaging. Mean LATT was determined as the time for contrast to transit through the LA during the first pass. In an invasive study group undergoing clinically indicated cardiac catheterization (n=25), LATT normalized by R-R interval (nLATT) was closely associated with LV early diastolic pressure (r=0.850, P=0.001), LV end-diastolic pressure (r=0.910, P<0.001), and mean diastolic pressure (r=0.912, P<0.001). In a larger noninvasive group (n=56), nLATT was prolonged in patients with LV systolic dysfunction (n=47) (10.1±3.0 versus 6.6±0.7 cardiac cycles in normal control subjects, n=9; P<0.001). Using a linear regression equation derived from the invasive group, noninvasive subjects were divided into 3 subgroups by estimated LV end-diastolic pressure: ≤10 mm Hg, 11 to 14 mm Hg, and ≥15 mm Hg. There were graded increases from low to high LV end-diastolic pressure subgroups in echocardiographic mitral medial E/e' ratio: 9±5, 11±4, and 13±3 (P=0.023); in B-type natriuretic peptide (interquartile range): 44 (60) pg/mL, 87 (359) pg/mL, and 371 (926) pg/mL (P=0.002); and in N-terminal pro-B-type natriuretic peptide: 57 (163) pg/mL, 208 (990) pg/mL, and 931 (1726) pg/mL (P=0.002), demonstrating the ability of nLATT to assess hemodynamic status.
nLATT by cardiac MR is a promising new parameter of LV filling pressure that may provide graded noninvasive hemodynamic assessment.
左心房（LA）大小和功能反映左心室（LV）的血液动力学。在本研究中，我们开发了一种通过 MRI 确定 LA 循环通过时间（LATT）的新方法，并证明其与 LV 充盈压密切相关。
所有受试者均前瞻性入组并接受对比增强 MRI 动态成像。平均 LATT 被确定为对比剂在第一通过期间通过 LA 的时间。在进行临床指示性心导管检查的侵入性研究组（n=25）中，通过 R-R 间隔标准化的 LATT（nLATT）与 LV 早期舒张压（r=0.850，P=0.001）、LV 舒张末期压（r=0.910，P<0.001）和平均舒张压（r=0.912，P<0.001）密切相关。在更大的非侵入性组（n=56）中，LV 收缩功能障碍患者的 nLATT 延长（n=47）（10.1±3.0 与正常对照组 9 例中的 6.6±0.7 个心动周期；P<0.001）。使用来自侵入性组的线性回归方程，通过估计的 LV 舒张末期压将非侵入性受试者分为 3 个亚组：≤10mmHg、11-14mmHg 和≥15mmHg。随着 LV 舒张末期压亚组从低至高，超声心动图二尖瓣中 E/e'比值逐渐升高：9±5、11±4 和 13±3（P=0.023）；B 型利钠肽（四分位距）：44（60）pg/mL、87（359）pg/mL 和 371（926）pg/mL（P=0.002）；N 末端 pro-B 型利钠肽：57（163）pg/mL、208（990）pg/mL 和 931（1726）pg/mL（P=0.002），表明 nLATT 能够评估血液动力学状态。
心脏 MRI 中的 nLATT 是一种有前途的 LV 充盈压新参数，它可以提供分级的无创血液动力学评估。
