Calculated Left Ventricular Ejection Fraction Research Articles

Preprocedural global myocardial work index independently predicts NT-proBNP in patients undergoing transcatheter aortic valve replacement: a prospective study

Abstract Global myocardial work index is a novel echocardiographic parameter of the left ventricular (LV) function, which may overcome the load-sensitvity of the traditional functional measures by measuring LV deformation in the context of simultaneous pressures. This approach may gain particular importance in pressure overload states, such as patients with severe aortic stenosis. However, the longitudinal changes of this recently introduced measure are scarcely investigated in this population, and data are also lacking about its association with functional improvement following transcatheter aortic valve replacement (TAVR). Accordingly, our aim was to investigate the clinical determinants of preoperative and also postoperative GMWI in patients undergoing TAVR. Eighty-four patients (54%% male, age: 79±6 years) were enrolled. Prior to the procedure, subjects underwent echocardiographic investigation and the detailed medical history was also recorded. Serum NT-proBNP levels were also measured. We calculated LV ejection fraction and LV end-diastolic volume (EDV), and speckle-tracking analysis was performed to measure global longitudinal strain (GLS). As an accepted method of its estimation, LV pressure curve was generated by adding the mean aortic valve gradient to the systolic blood pressure. Using these measures, global myocardial work index (GMWI) was quantified by commercially available software. 12 months after the procedure, the patients underwent a follow-up echocardiographic examination, and at that time point we determined the same measures. At follow-up, GLS has significantly increased (-13.5±4.5 vs. -15.2±3.6%; p<0.001), while GMWI was significantly lower at the follow-up assessment (1913±786 vs. 1666±594 mmHg%, p<0.01). Compared to the preoperative values, LVEDV also showed a significant decrease at follow-up (115±46 vs. 105±41 mL, p<0.01). Using multivariable analysis, atrial fibrillation (β=0.36; p<0.001) ischemic heart disease (β=0.20; p<0.05) and also GMWI (β=-0.22; p<0.05) were found to be independent predictors of the postoperative NT-proBNP (R2=0.36; overall p<0.001). Importantly, by replacing GMWI to GLS, the latter did not enter the model as a predictor (β=0.17, p=0.11). TAVR significantly alters LV functional and morphological measures. Regarding the functional outcome of the patients, different clinical factors influence NT-proBNP after the procedure. Possibly due to its significant load dependency, preoperative GLS failed to predict NT-proBNP at follow-up, while GMWI was an independent precictor of NT-proBNP at follow up along with atrial fibrillation and ischemic heart disease. GMWI may serve as a useful imaging marker of preprocedural patient assessment before TAVR.

Echocardiography Core Laboratory Reproducibility of Cardiac Safety Assessments in Cardio-Oncology

As the potential for cancer therapy-related cardiac dysfunction is increasingly recognized, there is a need for the standardization of echocardiographic measurements and cut points to guide treatment. The aim of this study was to determine the reproducibility of cardiac safety assessments across two academic echocardiography core laboratories (ECLs) at the University of Pennsylvania and the Duke Clinical Research Institute. To harmonize the application of guideline-recommended measurement conventions, the ECLs conducted multiple training sessions to align measurement practices for traditional and emerging assessments of left ventricular (LV) function. Subsequently, 25 echocardiograms taken from patients with breast cancer treated with doxorubicin with or without trastuzumab were independently analyzed by each laboratory. Agreement was determined by the proportion (coverage probability [CP]) of all pairwise comparisons between readers that were within a prespecified minimum acceptable difference. Persistent differences in measurement techniques between laboratories triggered retraining and reassessment of reproducibility. There was robust reproducibility within each ECL but differences between ECLs on calculated LV ejection fraction and mitral inflow velocities (all CPs<0.80); four-chamber global longitudinal strain bordered acceptable reproducibility (CP=0.805). Calculated LV ejection fraction and four-chamber global longitudinal strain were sensitive to small but systematic interlaboratory differences in endocardial border definition that influenced measured LV volumes and the speckle-tracking region of interest, respectively. On repeat analyses, reproducibility for mitral velocities (CP=0.940-0.990) was improved after incorporating multiple-beat measurements and homogeneous image selection. Reproducibility for four-chamber global longitudinal strain was unchanged after efforts to develop consensus between ECLs on endocardial border determinations were limited primarily by a lack of established reference standards. High-quality quantitative echocardiographic research is feasible but requires a commitment to reproducibility, adherence to guideline recommendations, and the time, care, and attention to detail to establish agreement on measurement conventions. These findings have important implications for research design and clinical care.

Recurrent Syncope Due to Torsades de Pointes in a 41-Year-Old Woman With an Empty Sella, Anterior Pituitary Insufficiency, and a Long-QT Interval

A 41-year-old woman was admitted to our emergency room (ER) because of recurrent syncope. ECG monitoring in the ER showed episodes of sustained but self-limiting torsades de pointes ventricular tachycardia (Figure 1). Two more episodes of syncope occurred in the ER. Intravenous magnesium was administered. Echocardiography revealed a severely impaired left ventricular (LV) function (online-only Data Supplement Movie I). The patient was immediately transferred to the cardiac catheterization laboratory for further assessment. Coronary artery disease was excluded by coronary angiography. LV angiography confirmed global hypokinesia (online-only Data Supplement Movie II). The calculated LV ejection fraction was 30%. During the procedure a temporary pacemaker was placed in the right ventricle. Pacing was initiated at a rate of 80 bpm, and the patient was transferred to the coronary care unit. No more episodes …

Apical Rotation Assessed by Speckle-Tracking Echocardiography as an Index of Global Left Ventricular Contractility

Left ventricular (LV) apical rotation and twist can be estimated noninvasively by speckle-tracking echocardiography (STE). In this study, we tested whether apical rotation is an accurate index of LV contractility. We measured LV basal and apical rotation by STE in 11 open-chest anesthetized mongrel dogs under 8 different inotropic stages before and after ligation of either left anterior descending (n=6) or circumflex coronary artery (n=5). We measured LV pressure simultaneously with a high-fidelity pressure catheter and calculated LV ejection fraction (EF) with the biplane Simpson method and 2D echocardiography. Maximal positive dP/dt (dP/dt(max)) was used as the gold standard measurement of LV contractility. We compared LV twist and apical rotation and EF against dP/dt(max) by linear mixed model. LV apical rotation and twist showed dose-dependent increases and decreases after dobutamine and esmolol infusion, respectively. However, basal rotation did not change significantly during different inotropic conditions. There was a stronger association between dP/dt(max) and LV twist (R(2)=0.747, P<0.001) and apical rotation (R(2)=0.726, P<0.001) than between dP/dt(max) and EF (R(2)=0.408, P<0.001), and this trend was more apparent with coronary ligation irrespective of the ligation site. There was also a high association between dP/dt(max) and apical rotation alone, both with (R(2)=0.805, P<0.001) and without (R(2)=0.748, P<0.001) coronary ligation. Apical rotation alone showed comparable accuracy to LV twist. Apical rotational velocity also showed a high association with dP/dt(max) (R(2)=0.669, P<0.001) and LV twist (R(2)=0.892, P<0.001). Apical rotation assessed by STE is an effective noninvasive index of global LV contractility and is more closely related to dP/dt(max) than LV EF.

Abstract 718: Head-to-Head Comparison of Apical Rotation versus Mitral Annular Systolic Velocity for Estimation of Global Left Ventricular Contractility

We sought to test whether mitral annular systolic velocity by tissue Doppler (S′) and apical rotation by speckle tracking echocardiography (AR) can represent global left ventricular (LV) contractility. We measured AR and S′ in nine open chest anesthetized mongrel dogs under eight different inotropic stages before and after ligation of left anterior descending (LAD, n=6) or circumflex coronary artery (LCX, n=3). We measured LV pressure simultaneously with a high-fidelity pressure catheter and calculated LV ejection fraction (EF) with the biplane Simpson’s method. Maximal positive dP/dt (dP/dt max ) was used as the gold standard measurement of LV contractility. We compared AR and S′ and EF against dP/dt max by linear regression. Both S′ and AR showed dose-dependent increases and decreases following dobutamine and esmolol infusion, respectively. There was a stronger association between dP/dt max and AR (r=0.820, P &lt;0.001) and S′ (r=0.784, P &lt;0.001) than between dP/dt max and EF (r=0.567, P &lt;0.001), and this trend was more apparent with coronary ligation. There was also a good correlation between AR and S′ with (r=0.690, P &lt;0.001) and without (r=0.740, P &lt;0.001) coronary ligation. Both AR and S′ are effective noninvasive indices of global LV contractility irrespective of coronary ligation and have better accuracy than LV EF.

A Comparison between QLAB and TomTec Full Volume Reconstruction for Real Time Three‐Dimensional Echocardiographic Quantification of Left Ventricular Volumes

To compare the interobserver variability and accuracy of two different real time three-dimensional echocardiography (RT3DE) analyzing programs. Forty-one patients (mean age 56 +/- 11 years, 28 men) in sinus rhythm with a cardiomyopathy and adequate 2D image quality underwent RT3DE and magnetic resonance imaging (MRI) within one day. Off-line left ventricular (LV) volume analysis was performed with QLAB V4.2 (semiautomated border detection with biplane projections) and TomTec 4D LV analysis V2.0 (primarily manual tracking with triplane projections and semiautomated border detection). Excellent correlations (R(2) > 0.98) were found between MRI and RT3DE. Bland-Altman analysis revealed an underestimated LV end-diastolic volume (LV-EDV) for both TomTec (-9.4 +/- 8.7 mL) and QLAB (-16.4 +/- 13.1 ml). Also, an underestimated LV end-systolic volume (LV-ESV) for both TomTec (-4.8 +/- 9.9 mL) and QLAB (-8.5 +/- 14.2 mL) was found. LV-EDV and LV-ESV were significantly more underestimated with QLAB software. Both programs accurately calculated LV ejection fraction (LV-EF) without a bias. Interobserver variability was 6.4 +/- 7.8% vs. 12.2 +/- 10.1% for LV-EDV, 7.8 +/- 9.7% vs. 13.6 +/- 11.2% for LV-ESV, and 7.1 +/- 6.9% vs. 9.7 +/- 8.8% for LV-EF for TomTec vs. QLAB, respectively. The analysis time was shorter with QLAB (4 +/- 2 minutes vs. 6 +/- 2 minutes, P < 0.05). RT3DE with TomTec or QLAB software analysis provides accurate LV-EF assessment in cardiomyopathic patients with distorted LV geometry and adequate 2D image quality. However, LV volumes may be somewhat more underestimated with the current QLAB software version.

Spontaneous ventricular arrhythmias following partial left ventriculectomy for nonischemic dilated cardiomyopathy: relation to hemodynamics and survival.

The study assessed the value of ambulatory electrocardiogram (AECG) monitoring for identification of patients who are at increased risk for cardiac death or arrhythmic event following partial left ventriculectomy (PLV). Furthermore, the impact of PLV and its hemodynamics on the occurrence of spontaneous ventricular arrhythmias was assessed in long-term survivors. In 32 idiopathic dilated cardiomyopathy patients who underwent PLV, ambulatory ECG (AECG) was performed preoperatively, early postoperatively, and 6 months and 12 months after surgery. In 17 of 19 patients who survived > 12 months after the procedure, left ventricular (LV) angiography was performed at the same time points and was used to calculate LV ejection fraction, and end-diastolic and end-systolic wall stress. During a mean follow-up of 478 +/- 405 days, 11 cardiac events occurred. Cox univariate regression revealed frequency of premature ventricular contractions > 30/hour at baseline (p = 0.0213) and duration of heart failure symptoms (p = 0.0226) as predictors of cardiac death or arrhythmic event after PLV. In a multivariate analysis, only frequency of premature ventricular contractions > 30/hour was a significant predictor. There was no change in the frequency or severity of ventricular arrhythmias after PLV. However, frequency of premature ventricular contractions correlated with LV end-diastolic stress (r = 0.35, p = 0.013), and ejection fraction (r = -0.34, p = 0.016). Preoperative AECG monitoring may help stratification of PLV patients. Serial AECG did not show that PLV influence the incidence or the complexity of spontaneous ventricular arrhythmias. In contrast, it appears that a hemodynamically "successful" procedure may decrease the incidence of ventricular arrhythmias.

Echocardiographic Assessment of Left Ventricular Remodeling: Are Left Ventricular Diameters Suitable Tools?

Objectives. We sought to analyze the value of echocardiographic left ventricular (LV) diameters in assessing LV remodeling.Background. LV diameters are easily measured and commonly used as a substitute for volumetric analysis to evaluate LV remodeling caused by ventricular overload or dysfunction. However, the impact of these measurements on outcome is disputed, suggesting that they may not adequately assess LV remodeling.Methods. M-mode echocardiographically measured LV dimensions and the derived LV ejection fraction and end-systolic wall stress were compared with LV volumes and the derived LV ejection fraction and wall stress using the biplane Simpson rule. These measurements were made prospectively and simultaneously in 463 patients (289 men, 174 women; mean [±SD] age 62 ± 15 years), including 46 normal subjects, 52 with aortic regurgitation, 253 with mitral regurgitation and 112 with LV dysfunction.Results. The correlation between diameter and volume was good at end-systole (r = 0.91, p < 0.0001) and end-diastole (r = 0.86, p < 0.0001). However, the relation was exponential, and the 95% confidence interval increased with increasing diameter. The calculated LV ejection fraction and wall stress using LV diameter and volume correlated linearly with a limited range of error (r = 0.96, SEE = 5%, p < 0.0001 and r = 0.95, SEE = 20 g/cm2, p < 0.0001, respectively).Conclusions. For assessing LV remodeling, LV diameters measured by M-mode echocardiography allow acceptable estimation of LV ejection fraction and wall stress and correlate significantly with LV volumes but are hindered by a wide range of error for assessment of LV size, especially for enlarged ventricles, suggesting that measurement of LV volume should be the preferred method of echocardiographically assessing LV remodeling.