Left ventricular filling pressure assessment using left atrial transit time by cardiac magnetic resonance imaging.
BACKGROUND
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.


RESULTS
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.


CONCLUSIONS
nLATT by cardiac MR is a promising new parameter of LV filling pressure that may provide graded noninvasive hemodynamic assessment.
St Francis Hospital, Research Department, State University of New York-Stony Brook, 100 Port Washington Blvd., Roslyn, NY 11576, USA. Jane.Cao@chsli.org
Jie J
JJ
Cao
Yi
Y
Wang
Jeannette
J
McLaughlin
Elizabeth
E
Haag
Peter
P
Rhee
Michael
M
Passick
Rena
R
Toole
Joshua
J
Cheng
Andrew D
AD
Berke
Justine
J
Lachman
Nathaniel
N
Reichek
D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D016279:Atrial Function, Left; D015415:Biomarkers / Q000097:blood; D016009:Chi-Square Distribution; D003287:Contrast Media; D018618:Echocardiography, Doppler, Color; D018619:Echocardiography, Doppler, Pulsed; D005260:Female; D006325:Heart Atria / Q000503:physiopathology; D006801:Humans; D016014:Linear Models; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D020097:Natriuretic Peptide, Brain / Q000097:blood; D009518:New York; D010446:Peptide Fragments / Q000097:blood; D011237:Predictive Value of Tests; D011446:Prospective Studies; D013997:Time Factors; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000503:physiopathology; D016277:Ventricular Function, Left; D017725:Ventricular Pressure
D015415:Biomarkers; D003287:Contrast Media; D010446:Peptide Fragments; C109794:pro-brain natriuretic peptide (1-76); D020097:Natriuretic Peptide, Brain