Objective: To report the current status of speckle tracking techniques in evaluation of fetal myocardial deformation. Methods: A variety of non-Doppler ultrasound methods are available using offline analysis of standard four-chamber and short axis views of the heart. Results: Most reports have used techniques developed for the measurement of strain and strain rate in the adult heart and produced conflicting descriptions of gestational changes in strain. Myocardial velocities usually reflect mean modal velocities and are lower than the peak velocities obtained using Doppler techniques. Conclusions: In the fetus, most current methods of acquisition result in frame rates that are too low, and the fetal heart size is too small to achieve reliable measures of fetal myocardial deformation.
Objectives: To compare myocardial deformation patterns in fetuses with congenital heart disease (CHD) with our reference range using speckle tracking echocardiography. Methods: We prospectively stored and analyzed 4-chamber loops of 28 fetuses with CHD (median gestation 27 weeks, range 20.9–37.0). The peak longitudinal left (LVs) and right (RVs) ventricular free wall Lagrangian strain and LV/RV strain ratio were measured from Syngo VVI software- (Siemens) derived original coordinates. Strain values from the first examination were compared with normative data from the same population using ANOVA with post hoc tests and serial examinations described in 14 fetuses. Results: Simple shunt lesions (0.82) and shunts with pulmonary stenosis or atresia (0.93) had reduced mean LV/RV strain ratios compared to normal fetuses (1.01; 95% CI 0.97–1.05). Fetuses with hypoplastic left heart had the lowest (0.29), and those with Ebstein the highest (1.55), LV:RV ratio. Serial measurements showed increased LVs in aortic coarctation and aortic stenosis, but not in one developing important mitral regurgitation. Increased right ventricular loading in a fetus developing pulmonary regurgitation was associated with increasing RVs. Conclusions: Myocardial strain reflects the changing physiology of fetal CHD. Speckle tracking might be a useful tool to study the progress of myocardial function in affected fetuses.
Background
Several clinical risk factors for death and heart transplantation have been identified in patients with Fontan circulation. It is unknown whether cardiac magnetic resonance (CMR) measurements of ventricular size and function are independently associated with these outcomes and further improve risk stratification.
Methods and Results
Data on Fontan patients who had a CMR study from 1/2002 to 1/2011 were retrospectively reviewed. The endpoint was time to death or listing for heart transplantation after the CMR study. The median age of the 215 patients was 18.3 years [25th, 75th percentiles: 14, 26] with a median age at Fontan of 3.6 years [2.3, 7.1]. Over a median post-CMR follow-up period of 4.1 years [2.6, 6.2], 24 patients (11%) reached the endpoint: 20 deaths, 3 transplants, and 1 transplant listing. In a multivariable Cox regression model with clinical parameters only, protein losing enteropathy (PLE) was associated with transplant-free survival. A multivariable model including clinical and CMR parameters showed that in addition to PLE, ventricular end-diastolic volume (EDVi) >125 mL/BSA1.3 was associated with transplant-free survival. A likelihood-ratio test comparing the 2 models showed that the addition of EDVi resulted in a significantly improved endpoint prediction (P<0.001) — C-index increased from 0.63 to 0.79.
Conclusions
CMR-derived ventricular EDVi is an independent predictor of transplant-free survival late after the Fontan operation and adds incremental value over clinical symptoms alone for risk stratification.
Aim: To evaluate the feasibility of offline anatomic M-mode (AMM) to study fetal atrioventricular annulus long-axis displacement (LAD) and compare its performance against real-time conventional M-mode (MM). Material and Methods: Paired AMM and MM LAD studies were recorded prospectively in 54 fetuses, and performance was compared. Insonation angles were less than 30° in all but 4 cases. The overall feasibility of AMM was tested in a composite total sample of 91 normal singleton pregnancies (median gestational age 23+6 weeks, range 12–36). AMM LAD was measured by placement of a virtual M-mode line on digitally stored raw data of fetal 4-chamber video loops. We studied annulus LAD at the lateral mitral (left ventricle; LV), proximal mitral (intraventricular septum; IVS), and lateral tricuspid (right ventricle; RV) myocardial segments. We compared LAD and its regression with gestational age measured using both methods in paired studies and AMM in the whole cohort. Results: Annulus LAD was measured using AMM, in all cases and segments, irrespective of cardiac axis alignment to the ultrasound beam. Good correlation existed between AMM and MM (RV r = 0.901, LV r = 0.899, IVS r = 0.815, p < 0.001). AMM recorded higher LAD values than MM in RV [mean 6.17 (SD 1.46) vs. 5.82 (SD 1.74) mm, p = 0.002] and LV [mean 4.18 (SD 1.11) vs. 3.98 (SD 1.12), p = 0.007]. Both methods showed LAD in RV > LV > IVS and a significant gestational increase in LAD values in all segments (p < 0.001) Conclusions: AMM permits offline evaluation of fetal longitudinal myocardial function in routinely obtained 2D fetal heart images with similar values to conventional MM in paired studies recorded <30°.
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