Rena Toole

Value of Two-Dimensional Speckle Tracking and Real Time Three-Dimensional Echocardiography for the Identification of Subclinical Left Ventricular Dysfunction in Patients Referred for Routine Echocardiography

Background: While speckle tracking echocardiography (2DSTE) can be used to study longitudinal, circumferential, and radial function, real time 3D echocardiography (3DE) generates dynamic time–volume curves, offering a wide array of new parameters for characterizing mechanical and volumetric properties of the left ventricle (LV). Our aim was to investigate the merit of these new techniques to separate normal from abnormal echocardiograms as well as to identify subclinical disease in reportedly normal subjects. Methods: Eighty‐one patients (mean age 61 ± 16 years) underwent standard 2D echocardiography (2DE) enhanced by 2DSTE and 3DE. The data included LV volumes and ejection fraction (EF), velocities, strain/strain rate, and peak ejection/filling rates. The patients were divided into Group 1: normal (n = 42) and Group 2: abnormal (n = 39) on the basis of an expert interpretation of the resting 2DE. Results: Global longitudinal strain (%) was 17 ± 4 in Group1 and 14 ± 4 in Group2 (P < 0.002). Strain rates (SR, 1/sec) at peak systole (1.1 ± 0.2 vs 0.9 ± 0.3, P < 0.001) and early diastole (1.3 ± 0.3 vs 0.9 ± 0.3, P < 0.001) were also higher in Group1. Three‐dimensional peak ejection and filling rates (EDV/sec) were significantly higher in Group1 (−2.5 ± 0.4 vs −2.1 ± 0.7, and 1.8 ± 0.2 vs 1.5 ± 0.5, P < 0.002, P < 0.001, respectively). The best discriminatory power for predicting a normal 2DE was systolic SR with a sensitivity of 82% and a specificity of 54% using a cutoff value of 1.09. Interestingly, 19/41 (46%) of Group1 patients had systolic SR < 1.09, suggesting subclinical disease. Conclusions: 2DSTE and 3DE can discriminate between normal and abnormal echocardiograms and have the potential to detect subclinical LV dysfunction.

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. Methods and 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.

Feature Tracking: a novel method to analyze myocardial strain: Results from the CMR strain study in healthy volunteers

Objective We sought to determine normal gender-specific strain values in healthy subjects using Feature Tracking (FT-MRI).

EVALUATION OF DIASTOLIC FUNCTION BY CARDIAC MAGNETIC RESONANCE IMAGING USING A NOVEL FEATURE TRACKING TECHNIQUE AND COMPARISON WITH ECHOCARDIOGRAPHY IN HEALTHY SUBJECTS

Left ventricular diastolic function is not routinely evaluated by cardiac magnetic resonance imaging (MRI). Feature Tracking (FT-MRI) is a novel tissue tracking method, which can be easily used to derive myocardial velocity. We sought to determine the feasibility of evaluating diastolic function by

ASSESSMENT OF GLOBAL AND REGIONAL STRAIN IN RELATION TO INFARCT SIZE AND LOCATION USING FEATURE TRACKING MAGNETIC RESONANCE IMAGING IN PATIENTS WITH MYOCARDIAL INFARCTION

Background: Feature tracking (FT-MRI) is a novel method for assessment of myocardial strain that provides multi-planar strain data without the need for tagged images. The goal of our study was to characterize left ventricular (LV) global and regional strains in patients with prior myocardial infarction (MI) using FT-MRI. Methods: Eighty patients with prior MI were grouped by infarct location {left anterior descending (LAD), left circumlex (LCx), right coronary (RCA)}. Scar quantiication was done by computer-assisted planimetry (Medis Qmass v7.2) of gadolinium enhanced delayed images and scar percentage was determined. Global and regional circumferential endocardial (Ecc endo) and epicardial (Ecc epi) and longitudinal (Ell) strains were derived from long and short axis planes. Semi-automated tracing of endocardial and epicardial borders using FT-MRI (Diogenes MRI, Tomtec Systems) was performed and strains were mapped to a 17 segment AHA model. Repeated measures ANOVA was used to compare normal strain values from 60 healthy subjects to MI patients controlling for scar percentage. Results: The mean age was 64.4(12) years, mean ejection fraction (EF) 42(11)% and mean scar percentage 17(9)%. Peak global Ecc strains were decreased in LAD (endo: -13.7 (5)%, epi: -8.4 (3)%) and RCA infarcts (endo: -16.1(6)%, epi: -9.6%) compared to normals (Ecc endo= -24 (4)%, Ecc epi= -16.1 (3)%, all with p<0.001). However, only peak global Ecc epi was decreased in LCX infarcts (LCx= -10.6 (3)%, p=0.01) compared to normals . Peak global Ell strain was reduced in LAD infarcts (-9.4 (3)% vs -16.2(5)% in normals, p=0.04) but was not signiicantly reduced in other infarcts {LCx MI: -10.2 (5)%, RCA MI: -14.7 (5)%, p=NS}. The best correlate of reduced LVEF in MI patients was reduced global Ecc Endo (r =0.82, p<0.0001), followed by global Ecc Epi (r=0.64, p <0.0001), scar territory percent (r=0.53, p<0.0001) and global Ell (r=0.43, p< 0.0001). Conclusion: FT-MRI permits detailed assessment of global and regional strains in patients with MI. Global Ecc was decreased in all MI patients, while Ell was reduced only in LAD infarcts. The best correlate of reduced LV EF was reduced global Ecc endo strain, which was superior to infarct size.

Assessment of left ventricular filling pressure using mean left atrial transit time from contrast enhanced dynamic MRI

Left atrial (LA) size and function are often regarded as a reflection of left ventricular (LV) hemodynamics. Purpose:In this study we investigated the hemodynamic correlates of contrast transit time within the left atrium (LA) in patients with LV systolic dysfunction by cardiac magnetic resonance imaging (CMR).

Quantitative assessment of global and regional strain in relation to infarct size in patients with myocardial infarction

Assessment of regional and global left ventricular (LV) function and strain are important in the setting of prior myocardial infarction (MI). Feature tracking (FT-MRI) is a novel cardiac MRI method for assessment of myocardial strain, similar to speckle tracking in 2-D echocardiography, which provides multi-planar strain data without the need for tagged images.