Left atrial and left ventricular function in healthy children and young adults assessed by three dimensional echocardiography

Assessment of left ventricular systolic function using two- and three-dimensional speckle tracking echocardiography among healthy preschool-age pediatric children

Background

Accurate measurements of left ventricular (LV) volumes and function are important in the management of patients with various cardiac abnormalities. Two-dimensional (2D) speckle tracking echocardiography (STE) is shown to be accurate in detecting subclinical myocardial dysfunction when most of the conventional echocardiography parameters were normal. Three-dimensional (3D) echocardiography is a new noninvasive imaging technique that has been shown to be accurate in determining cardiac volume and performance. Establishment of normal range values of 3D STE over a different range of ages is crucial before applying this recent technology in clinical applications. This study aimed to assess feasibility of 3D LV STE and establish normal values for the LV systolic function among healthy Egyptian preschool-age pediatric population using 2D and 3D STE.

Results

A total of 200 subjects (95%) met the criteria for 2DSTE analysis, 10 were excluded from the 2D analysis and 180 subjects (85%) met the criteria for 3D STE analysis. Regarding the 2D STE GLS, the mean was -22.1345 ± 2.166%, GCS was f -19.02 ± 1.23%, and GRS was 42.25 ± 2.35%. There was a strongly positive significant correlation between age and 2D values of GLS (P = 0.001). The GCS showed a weakly positive nonsignificant correlation with age (P = 0.28), while GRS showed a strongly negative significant correlation with age (P = 0.001). Regarding the 3D STE data, GLS mean was -20.48 ± 1.526%, GCS mean was -13.90 ± 2.05%, while GRS mean was 47.21 ± 2.382%. 3D GLS values had a strongly positive significant correlation with age (P = 0.001). While GCS showed a weakly positive nonsignificant correlation (P = 0.955), GRS showed a strongly negative significant correlation (P = 0.001). Linear correlation analysis of 2D and 3D values of strain showed that GLS had a strongly positive significant correlation (P = 0.001), while GCS showed a weakly positive nonsignificant correlation (P = 0.161) and GRS showed a strongly positive significant correlation (P = 0.001).

Conclusions

3D global strain analysis using the 3D STE is feasible in the preschool-age pediatric population. Results were almost concordant with previous observations in most of the values except for GCS, especially 3D values which could be attributed to different vendor system used and different ethnicity. Further studies are required to reinforce these data using the GE vendor machine.

Multicentre reference values for cardiac magnetic resonance imaging derived ventricular size and function for children aged 0-18 years

Aims

Cardiovascular magnetic resonance (CMR) imaging is an important tool in the assessment of paediatric cardiac disease. Reported reference values of ventricular volumes and masses in the paediatric population are based on small cohorts and several methodologic differences between studies exist. We sought to create steady-state free precession (SSFP) CMR reference values for biventricular volumes and mass by combining data of previously published studies and re-analysing these data in a standardized manner.

Methods and results

A total of 141 healthy children (68 boys) from three European centres underwent cine-SSFP CMR imaging. Cardiac structures were manually contoured for end-diastolic and end-systolic phases in the short-axis orientation according to current standardized CMR post-processing guidelines. Volumes and masses were derived from these contours. Age-related reference curves were constructed using the lambda mu sigma method. Median age was 12.7 years (range 0.6–18.5). We report biventricular volumes and masses, unindexed and indexed for body surface area, stratified by age groups. In general, boys had approximately 15% higher biventricular volumes and masses compared with girls. Only in children aged <6 years old no gender differences could be observed. Left ventricle ejection fraction was slightly higher in boys in this study population (median 67% vs. 65%, P = 0.016). Age-related reference curves showed non-linear relations between age and cardiac parameters.

Conclusion

We report volumetric SSFP CMR imaging reference values for children aged 0–18 years old in a relatively large multi-centre cohort. These references can be used in the follow-up of paediatric cardiac disease and for research purposes.

Contemporary narrative review on left atrial strain mechanics in echocardiography: cardiomyopathy, valvular heart disease and beyond

Left atrial (LA) strain mechanics refer to the measurement of LA myocardial deformation expressed as a percentage, and have been gathering interest over the last decade with expanding research supporting their utility in multiple cardiovascular disorders. Measured through advanced dynamic imaging techniques which include tissue Doppler imaging (TDI) and two-dimensional (2D) speckle tracking echocardiography (STE), LA strain mechanics are affected by left ventricular diastolic dysfunction prior to the onset of functional and structural changes in the left ventricle (LV). There is a need for practising cardiologists to become more familiar with the clinical utility of LA strain mechanics. In this article, we begin by reviewing the physiologic function of the LA, using this as a basis for understanding LA strain mechanics. The focus of this review article is to provide a contemporary update on the utility of LA strain mechanics in a range of cardiovascular disorders, including atrial fibrillation (AF), hypertrophic cardiomyopathy (HCM), valvular pathologies, coronary artery disease (CAD) as well as systemic diseases, such as hypertension (HTN), obesity and diabetes mellitus (DM). This article also highlights the current limitations in more widespread clinical applications of LA strain mechanics, as well as outlining the future perspectives on the clinical applications of LA strain mechanics.

Indexing haemodynamic variables in young children

BACKGROUND

Haemodynamic studies in children are rare and most studies have included few subjects in the youngest age group. Haemodynamic variables need to be indexed to establish a reference of normality that is valid in all populations. The traditional way to index haemodynamic variables with body surface area (BSA) is complicated in young children due to its non-linear relationship with body weight (BW). We examined several haemodynamic variables in children by indexing them with BSA and BW.

METHODS

A single-centre, observational cohort study comparing non-indexed and indexed haemodynamic variables in children undergoing heart surgery (divided into three weight groups: 1-5 kg, >5-10 kg and >10-15 kg).

RESULTS

A total of 68 children were included in this study, mean age 11.1 months ± 11.1 month (range 0 to 43 months). All haemodynamic variables, cardiac output (CO), stroke volume (SV), total end-diastolic volume (TEDV), central blood volume (CBV) and active circulation volume (ACV), increased with weight without indexing (P < .05). Indexing variables with BW produced a more linear relationship for all haemodynamic variables between weight groups than BSA. The mean BSA-indexed haemodynamic values were CIBSA 3.5 ± 1.1 L/min/m2 and SVIBSA 27.3 ± 8.9 ml/min/m2 . The mean BW-indexed haemodynamic values were CIBW 180 ± 50 ml/min/kg and SVIBW 1.34 ± 0.38 ml/kg. Blood volume variables indexed with BW were TEDVBW 12.0 ± 2.8 ml/kg, CBVBW 21.3 ± 6.6 ml/kg and ACVBW 70.3 ± 15.2 ml/kg.

CONCLUSIONS

Indexing haemodynamic variables with BW produces a more appropriate body size-independent scale in young children than BSA.

SUMMARY STATEMENT

In this study, we studied indexing of haemodynamic variables and estimation of blood volumes in young children undergoing corrective heart surgery using an indicator dilution technology.

Assessment of biatrial function in clinically well pediatric bicaval heart transplantation patients by three-dimensional echocardiography

Atrial size and function are closely correlated with atrial contributions to cardiovascular performance. Therefore, in this study, we aimed to assess atrial size and function in pediatric heart transplantation (HTx) patients using three-dimensional echocardiography (3DE). We enrolled 33 clinically well pediatric HTx patients and 33 healthy controls with a similar distribution of sex and age to the HTx patients. All patients underwent two-dimensional echocardiography (2DE) and 3DE. 2DE- and 3DE-derived biatrial maximal volume (Vmax), minimal volume (Vmin), ejection volume (EV), ejection fraction (EF), volume before atrial contraciton (VpreA), passive EV, passive EF, active EV and active EF were obtained in all patients. The 3D left atrail (LA) Vmax, Vmin and VpreA increased significantly in HTx patients after being indexed by BSA, while 3D LAEV and passive EV decreased significantly (P < 0.05). Moreover, the 3D LAEF, LA passive EF, and LA active EF all decreased significantly in HTx patients (P < 0.05). The 3D right atrial (RA) Vmax, Vmin, and VpreA increased significantly in HTx patients (P < 0.05), while the 3D RAEF and RA passive EF decreased significantly in HTx patients (P < 0.05). 3DE-derived LAVmax, LAVpreA, LA passive EV, LAEF, and LA passive EF were all lower than the corresponding 2D parameters. 3DE-derived RAVpreA, RA passive EV and RAEF were all lower than the corresponding 2D parameters. Atrial sizes and function assessed by 3DE- and 2DE-derived parameters, yield significantly discordant results in pediatric HTx patients. 3DE confirms significantly enlarged atrial sizes and decreased atrial functions in pediatric HTx patients.

Mathematical modeling of cardiac function to evaluate clinical cases in adults and children

Time-varying elastance models can simulate only the pressure and volume signals in the heart chambers while the diagnosis of clinical cases and evaluation of different treatment techniques require more information. In this study, an extended model utilizing the geometric dimensions of the heart chambers was developed to describe the cardiac function. The new cardiac model was evaluated by simulating a healthy and dilated cardiomyopathy (DCM) condition for adults and children. The left ventricular ejection fraction, end-diastolic volume, end-diastolic diameter and diastolic sphericity index were 53.60%, 125 mL, 5.08 cm and 1.82 in the healthy adult cardiovascular system model and 23.70%, 173 mL, 6.60 cm and 1.40 in the DCM adult cardiovascular system model. In the healthy child cardiovascular system model, the left ventricular ejection fraction, end-diastolic volume, end-diastolic diameter and diastolic sphericity index were 59.70%, 92 mL, 4.10 cm and 2.26 respectively and 30.70%, 125 mL, 4.94 cm and 1.87 in the DCM child cardiovascular system model. The developed cardiovascular system model simulates the hemodynamic variables and clinical diagnostic indicators within the physiological range for healthy and DCM conditions proving the feasibility of this new model to evaluate clinical cases in adults and children.

Normal percentile curves for left atrial size in healthy children and adolescents

BACKGROUND

Despite the clinical utility of echocardiography to measure left atrial (LA) structure and function, there are scarcities of data about the percentiles of LA diameter (LA_D ), LA volume (LA_VOL ), and LA volume indexed by body surface area (LA_{VOL / BSA} ) from prospective population-based studies in healthy children and adolescents from the Southern Cone of Latin America.

METHODS

Echocardiographic studies were obtained in 1095 healthy subjects nonexposed to cardiovascular risk factors (5-24 years). Age- and sex-specific reference values of LA_D , LA_VOL , and LA_{VOL / BSA} were generated using parametric regression based on fractional polynomials.

RESULTS

After covariate analysis (ie, adjusting by age, body surface area), specific sex-specific percentiles were evidenced as necessaries. Age- and sex-specific 1st, 2.5th, 5th, 10th, 25th, 50th, 75th, 90th, 95th, 97.5th, and 99th percentile and curves were reported. Our percentiles showed high concordance and complementarity with what was previously reported for the population of North American, European, and Asiatic Populations.

CONCLUSIONS

In children and adolescents, the interpretation of the LA size requires sex-related percentiles. This study provides the largest Argentinean database concerning percentile curves of LA_D , LA_VOL , and LA_{VOL / BSA} obtained in healthy children and adolescents. These data are valuable in that they provide values with which data of populations of children, adolescents, and young adults can be compared.

Racial Variation in Echocardiographic Reference Ranges for Left Chamber Dimensions in Children and Adolescents: A Systematic Review

Echocardiography plays a critical role in the assessment of cardiac disease. Important differences in echocardiographically derived cardiac chamber dimensions have been previously highlighted in different population groups in adult studies, but this has not been systematically studied in children, whose body size changes throughout childhood. The aim of this study was to review the distribution of available reference ranges for the left cardiac chamber dimensions in older children and adolescents. The following electronic data bases were searched: Medline, Embase and Web of Science were searched to identify studies which have established echocardiographic reference ranges of left heart parameters in children and adolescents from 1975 to December 2017. There was no geographical limitation. All results were imported into Endnote. Retrieved articles were screened and data extracted by two independent reviewers. A total of 4398 studies were retrieved, with 36 studies finally included in this review. 29 (81%) references were from North America and European (Caucasians) populations, with only one study each from Africa and South America. Two-dimensional and M-mode techniques were the most commonly used echocardiography techniques. There were methodological variations in techniques and normalisation of references. Comparison of selected cardiac measures showed significant differences for interventricular septal thickness among Black African, Indian, German and US American children. Available echocardiographic references cannot be generalised to all settings and therefore, there is need for locally relevant reference ranges. Africa and South America are particularly under-represented. Future studies should focus on developing comprehensive echocardiographic reference ranges for children from different racial backgrounds and should use standardised techniques.

Adult echocardiographic nomograms: overview, critical review and creation of a software for automatic, fast and easy calculation of normal values

There is a crescent interest on normal adult echocardiographic values and the introduction of new deformation imaging and 3D parameters pose the issue of normative data. A multitude of nomograms has been recently published, however data are often fragmentary, difficult to find, and their strengths/limitations have been never evaluated.

AIMS

(I) to provide a review of current echocardiographic nomograms; (II) to generate a tool for easy and fast access to these data. A literature search was conducted accessing the National Library of Medicine using the keywords: 2D/3D echocardiography, strain, left/right ventricle, atrial, mitral/tricuspid valve, aorta, reference values/nomograms/normal values. Adding the following keywords, the results were further refined: range/intervals, myocardial velocity, strain rate and speckle tracking. Forty one published studies were included. Our study reveals that for several of 2D/3D parameters sufficient normative data exist, however, a few limitations still persist. For some basic parameters (i.e., mitral/tricuspid/pulmonary valves, great vessels) and for 3D valves data are scarce. There is a lack of studies evaluating ethnic differences. Data have been generally expressed as mean values normalised for gender and age instead of computing models incorporating different variables (age/gender/body sizes) to calculate z scores. To summarize results a software (Echocardio-Normal Values) who automatically calculate range of normality for a broad range of echocardiographic measurements according to age/gender/weight/height, has been generated. We provide an up-to-date and critical review of strengths/limitation of current adult echocardiographic nomograms. Furthermore we generated a software for automatic, easy and fast access to multiple echocardiographic normative data.

Diagnostic accuracy of electrocardiographic P wave related parameters in the assessment of left atrial size in dogs with degenerative mitral valve disease

The purpose of this research was to compare the accuracy of newly described P wave-related parameters (P wave area, Macruz index and mean electrical axis) with classical P wave-related parameters (voltage and duration of P wave) for the assessment of left atrial (LA) size in dogs with degenerative mitral valve disease. One hundred forty-six dogs (37 healthy control dogs and 109 dogs with degenerative mitral valve disease) were prospectively studied. Two-dimensional echocardiography examinations and a 6-lead ECG were performed prospectively in all dogs. Echocardiography parameters, including determination of the ratios LA diameter/aortic root diameter and LA area/aortic root area, were compared to P wave-related parameters: P wave area, Macruz index, mean electrical axis voltage and duration of P wave. The results showed that P wave-related parameters (classical and newly described) had low sensitivity (range=52.3 to 77%; median=60%) and low to moderate specificity (range=47.2 to 82.5%; median 56.3%) for the prediction of left atrial enlargement. The areas under the curve of P wave-related parameters were moderate to low due to poor sensitivity. In conclusion, newly P wave-related parameters do not increase the diagnostic capacity of ECG as a predictor of left atrial enlargement in dogs with degenerative mitral valve disease.

Pulmonary hypertension and cardiac hypertrophy in children recipients of orthotopic living related liver transplantation

Surgical stress, liberation of cytokines associated with re-perfusion injury, and long standing use of immune suppressive medications in children recipients of orthotopic living related liver transplantation (OLRLT) pose cardiovascular risk. Reported cardiovascular adverse effects vary from left ventricular wall thickening, hypertrophic cardiomyopathy to resting ECG abnormalities, asymptomatic ST depression following increased heart rate and ventricular arrhythmias. Twenty-five consecutive children recipients of OLRLT were assessed by conventional 2-D, M-mode echocardiography and Doppler. The mean age ± SD at transplantation and at enrollment in study was 6.3 ± 4.5 and 13.5 ± 5.6 years respectively. All children were on immunosuppressive medications, with tacrolimus being constant among all. Long-term post-transplant echocardiography revealed statistically significant interventricular septal hypertrophy among all (mean thickness 0.89 ± 0.16 cm), (P = 0.0001) in comparison to reference range for age, 24 had pulmonary hypertension (mean mPAP 36.43 ± 5.60 mm Hg, P = 0.0001), and early diastolic dysfunction with a mean Tei index of 0.40 ± 0.10. However cardiac function was generally preserved. Children recipients of OLRLT have cardiac structural and functional abnormalities that can be asymptomatic. Pulmonary hypertension, increased cardiac mass, de novo aortic stenosis and diastolic heart failure were among abnormalities encountered in the studied population. Echocardiography is indispensible in follow-up of children recipients of OLRLT.

Decreased left atrial myocardial strain in patients with suboptimal blood pressure control

BACKGROUND

Suboptimal blood pressure (BP) control is commonly observed in patients receiving antihypertensive agents, but the relationship between uncontrolled BP and left atrial (LA) impairment remains unknown.

METHODS

This study enrolled 279 hypertensive patients who had been medicated, as well as 85 matched normal controls. The BP of systolic <140 mmHg and diastolic<90 mmHg was defined as optimal (HT1 group, n=146), otherwise as suboptimal BP control (HT2 group, n = 133). LA myocardial function was assessed by the systolic (S_Sa), early diastolic (S_Ea), and late diastolic (S_Aa) LA strains.

RESULTS

Both the HT1 group and HT2 group had higher BP reading, thicker interventricular septum, larger LA volume index, and enhanced active atrial emptying fraction than the control group (all <0.05). When compared with normal subjects, hypertensive patients displayed obvious reduction in the S_Sa (50.0 ± 10.9 vs. 35.9 ± 8.0%), S_Ea (30.1 ± 7.7 vs. 18.5 ± 7.1%) and S_Aa (19.9 ± 6.4 vs. 17.8 ± 4.2%) (all p < 0.001). In addition to a further impaired S_Ea found in the HT2 group than in the HT1 group (17.2 ± 5.3 vs. 19.8 ± 8.3%, p = 0.002), the treated BP of >140/90 mmHg appeared an independent risk factor associated with the abnormal S_Ea (odds ratio, 2.957; interval of confidence, 1.614-5.415; p = 0.001).

CONCLUSIONS

Suboptimal BP control status in hypertensive patients is related to a further reduction of LA myocardial function assessed by the novel 2DSTI free strain, and suboptimal BP might be regarded as a composite risk factor and therefore a simplified treatment target. However, the prognostic value of LA free strain in patients with inability to achieve the BP target needs to be evaluated in future prospective studies.

Cardiac remodelling in a baboon model of intrauterine growth restriction mimics accelerated ageing

KEY POINTS

Rodent models of intrauterine growth restriction (IUGR) successfully identify mechanisms that can lead to short-term and long-term detrimental cardiomyopathies but differences between rodent and human cardiac physiology and placental-fetal development indicate a need for models in precocial species for translation to human development. We developed a baboon model for IUGR studies using a moderate 30% global calorie restriction of pregnant mothers and used cardiac magnetic resonance imaging to evaluate offspring heart function in early adulthood. Impaired diastolic and systolic cardiac function was observed in IUGR offspring with differences between male and female subjects, compared to their respective controls. Aspects of cardiac impairment found in the IUGR offspring were similar to those found in normal controls in a geriatric cohort. Understanding early cardiac biomarkers of IUGR using non-invasive imaging in this susceptible population, especially taking into account sexual dimorphisms, will aid recognition of the clinical presentation, development of biomarkers suitable for use in humans and management of treatment strategies.

ABSTRACT

Extensive rodent studies have shown that reduced perinatal nutrition programmes chronic cardiovascular disease. To enable translation to humans, we developed baboon offspring cohorts from mothers fed ad libitum (control) or 70% of the control ad libitum diet in pregnancy and lactation, which were growth restricted at birth. We hypothesized that intrauterine growth restriction (IUGR) offspring hearts would show impaired function and a premature ageing phenotype. We studied IUGR baboons (8 male, 8 female, 5.7 years), control offspring (8 male, 8 female, 5.6 years - human equivalent approximately 25 years), and normal elderly (OLD) baboons (6 male, 6 female, mean 15.9 years). Left ventricular (LV) morphology and systolic and diastolic function were evaluated with cardiac MRI and normalized to body surface area. Two-way ANOVA by group and sex (with P < 0.05) indicated ejection fraction, 3D sphericity indices, cardiac index, normalized systolic volume, normalized LV wall thickness, and average filling rate differed by group. Group and sex differences were found for normalized LV wall thickening and normalized myocardial mass, without interactions. Normalized peak LV filling rate and diastolic sphericity index were not correlated in control but strongly correlated in OLD and IUGR baboons. IUGR programming in baboons produces myocardial remodelling, reduces systolic and diastolic function, and results in the emergence of a premature ageing phenotype in the heart. To our knowledge, this is the first demonstration of the specific characteristics of cardiac programming and early life functional decline with ageing in an IUGR non-human primate model. Further studies across the life span will determine progression of cardiac dysfunction.

Quantification of ventricular unloading by 3D echocardiography in single ventricle of left ventricular morphology following superior cavo-pulmonary anastomosis and Fontan completion - a feasibility study

BACKGROUND

Three-dimensional echocardiography. (3DE) is comparable to cardiac magnetic resonance imaging for estimating ventricular volume in congenital heart diseases. However, there are limited data on estimation of ventricular volumes by 3DE in univentricular heart and change in ventricular volumes after surgical creation of cavopulmonary connection. We sought to quantify the unloading of the single ventricle of left ventricular. (LV) morphology by 3DE after superior cavopulmonary anastomosis. (SCPA) or Fontan operation over a period of 3 months and thereby derive a preliminary 3DE data set on this patient subset.

PATIENTS AND METHODS

Eighteen patients with functional single ventricle of LV morphology, who underwent SCPA or completion of Fontan circulation, were included in the study. Volume of the ventricle was estimated by 3DE before surgery and after surgery. (in the early postoperative phase and 3 months after surgery), and indexed end-diastolic volume. (EDV), end-systolic volume. (ESV), and ejection fraction. (EF) were derived.

RESULTS

Twelve patients underwent SCPA and six patients underwent staged completion of Fontan circulation. Before surgery, EDV was similar in both groups. There was a significant fall in EDV immediately after SCPA (from 48.3 ± 14.9 ml/m² to 39.5 ± 12.3 ml/m²). However, EDV increased at 3 months' follow-up to 41.3 ± 10.5 ml/m². There was no significant fall in EDV immediately after Fontan operation (47.2 ± 10.1 ml/m²-46.6 ± 14.2 ml/m²), but EDV continued to fall at 3 months of follow-up (44.7 ± 10. ml/m²). There was no significant change in ESV in either group, but EF fell significantly after SCPA.

CONCLUSIONS

We provide preliminary information on 3DE volume data of single ventricle of LV morphology and the pattern of unloading after SCPA and Fontan operation. Immediate significant volume unloading occurred after SCPA which tended to catch-up after 3 months, whereas continued fall in ventricular volume with time was noted after Fontan.

Left Atrial Volumes and Function by Three-Dimensional Echocardiography

Background—

Our study sought to (1) identify reference values for left atrial (LA) volumes and phasic function indices by 3-dimensional echocardiography (3DE) and compare them with those measured by 2-dimensional echocardiography (2DE) and (2) analyze their relationship with age, sex, body size, and left ventricular function. Accuracy and reproducibility of 3DE and 2DE have been also tested to evaluate the robustness of our data.

Methods and Results—

We obtained maximal, minimal, and preA LA volumes by 3DE and 2DE in 276 healthy volunteers (18–79 years; 57% women). Limits of normality for LA volumes and total LA emptying fraction were larger with 3DE than with 2DE (maximal LA volume: 43 versus 35 mL/m 2 ; preA LA volume: 31 versus 25 mL/m 2 ; minimal LA volume: 18 versus 14 mL/m 2 ; 53 versus 48%, respectively; P <0.001). 3DE LA volumes indexed by body surface area were similar in men and women and increased with age. On multivariable analysis, age, weight, and left ventricular systolic and diastolic function indices resulted as correlates of LA 3DE indices. LA volumes were tightly correlated with cardiac magnetic resonance measurements, yet more underestimated by 2DE versus 3DE (bias±SD: −17±16 versus −7±15 mL, respectively). Among all LA parameters, maximal LA volume and total emptying fraction were the most reproducible, including at test-retest and at expert versus trainee comparisons.

Conclusions—

This study provides reference values for LA 3DE volumes and function from a relatively large cohort of healthy subjects with a wide age range. Our data may help clinicians to identify LA remodeling and dysfunction.

Transpulmonary thermodilution (PiCCO) measurements in children without cardiopulmonary dysfunction: large interindividual variation and conflicting reference values

BACKGROUND

The PiCCO system, based on transpulmonary thermodilution, is one of the few tools available for continuous hemodynamic monitoring in children. However, published data for some of the derived variables reveal indexed values that seem questionable.

AIMS

The aim of this study was to collect data from hemodynamically normal children and compare these to existing reference values. Furthermore, we sought to explore if indexing some of the variables differently could improve the clinical application of the obtained values.

METHODS

This is a prospective observational study in a tertiary university hospital including 31 children without cardiopulmonary disease scheduled for major neurosurgery. Measurements were performed after induction of general anesthesia.

RESULTS

Median age was 8 months. PiCCO-derived median Cardiac Index (CI) was 3.8 l · min(-1) · m(-2) (range 2.6-6.6), reference range 3.0-5.0, median Global End-Diastolic Volume Index (GEDVI) was 366 ml · m(-2) (range 269-685), reference range 680-800, whereas median Extravascular Lung Water Index (EVLWI) was 12 ml · kg(-1) (range 7-31), reference range 3-7. All measured variables had a high interindividual variation, especially in children weighing less than 15 kg.

CONCLUSIONS

Values obtained by the PiCCO system in children have a wide range, and should therefore be interpreted with caution. Current reference values published for GEDVI and EVLWI are not applicable in children; the former is too high and the latter too low, and should not guide clinical practice. Indexing by other physiological indices may reduce this problem. Using current variables, we find GEDVI 280-590 ml · m(-2) and ELWI 7-27 ml · kg(-1) to be typical ranges for children.

Cardiac biomarkers indicate a need for sensitive cardiac imaging among long-term childhood cancer survivors exposed to anthracyclines

AIM

The role that plasma N-terminal pro-brain natriuretic peptide (NT-proBNP) and cardiac troponins T (cTnT) and I (cTnI) play in supplementing imaging to screen for cardiac late effects remains controversial and the impact of high-sensitivity cTnT and troponin-specific autoantibodies (cTnAAbs) remains unexplored. We studied the role of cardiac biomarkers as indicators of the late effects of anthracyclines among childhood cancer survivors.

METHODS

We measured NT-proBNP, cTnT, high-sensitivity cTnT, cTnI and cTnAAbs in 76 childhood cancer survivors at a median of 9 years after primary diagnosis. The survivors underwent conventional and real-time three-dimensional echocardiography and 62 underwent cardiac magnetic resonance imaging (MRI).

RESULTS

Of the survivors, four (5.3%) without risk factors for cardiotoxicity were cTnAAb-positive with an impaired cardiac function in MRI. Another four (5.3%) had an abnormal NT-proBNP level associated with an abnormal cardiac function and risk factors for cardiotoxicity. None showed measurable cardiac troponins, determined by the three different methods, with even the high-sensitivity cTnT-levels remaining normal.

CONCLUSION

Elevated plasma NT-proBNP or cTnAAbs indicated that childhood cancer survivors benefitted from being evaluated with modern imaging, despite normal function in conventional echocardiography. However, troponins did not seem to provide additional information on the late cardiotoxicity of anthracyclines.

Cardiac function after repair of tetralogy of fallot: how are the atria performing? pilot study by cardiac magnetic resonance imaging

The atria of the heart function as reservoir, conduit, and active pump and are critical for ventricular filling and cardiac output. We sought to evaluate right (RA) and left atrial (LA) function in patients after tetralogy of Fallot (TOF) repair by using cardiovascular magnetic resonance. Twelve TOF patients, age 16.7 ± 6.1 years, weight 50.9 ± 14.9 kg, were compared to 10 healthy volunteers, age 18.8 ± 6.8 years, weight 52.3 ± 20.8 kg. Both atria and both ventricles were imaged in short-axis planes by Steady State Free Precession. Volume changes and all derived atrial functional parameters were calculated from the volume/time curves obtained after segmentation on the cine images. Blood flow across the AV valves was used to define ventricular diastolic dysfunction. TOF patients showed similar maximal RA volume compared to controls, but increased volumes at mid-diastole (p < 0.05), resulting in a decreased cyclic volume change and atrial filling fraction (p < 0.01), and a decreased passive emptying volume and fraction (p < 0.01). In patients with diastolic dysfunction, conduit volume was increased (p < 0.05), and active emptying volume and fraction tended to be increased, respectively. No significant changes were found in LA, except for a decreased passive emptying fraction (p < 0.05). RA function and particularly reservoir function are impaired in TOF patients. The RA conduit/reservoir ratio is increased and reflects the lost of the ability of the atrium to fill the ventricle by pulsatile flow.

Left atrial function in patients with mitral valve regurgitation

The purpose of this study was to assess left atrial (LA) function and myocardial mechanics in patients with degenerative mitral regurgitation (MR). Eighty patients with degenerative MR and twenty control subjects were included prospectively. LA volume (LAV) and right atrial (RA) volume (RAV) were measured with three-dimensional transthoracic echocardiography at three phases of the cardiac cycle as maximal volume (LAVmax and RAVmax), minimal volume (LAVmin and RAVmin), and volume before atrial contraction (LAVpre-A and RAVpre-A). From these volumes, active stroke volume (SV), distensibility, and emptying fraction were calculated. LA strain and strain rate were measured with vector velocity imaging on four- and two-chamber views. Left ventricular (LV) filling pressures were increased in patients with severe MR (E/E': 16 ± 4 vs. 10 ± 3 in control subjects). LAVmax, LAVmin, and LAVpre-A all increased with increasing MR volume. As LAVpre-A increased, both LA total SV (r = 0.68, P < 0.001) and passive filling volume (r = 0.76, P < 0.001) increased. LA active SV increased with LAVpre-A up to a certain point, upon which it decreased despite further increased LAVpre-A (r = 0.53, P < 0.001). LA late negative strain decreased with increasing MR volume. A positive correlation existed between LA late negative strain and LA active emptying fraction (r = 0.55, P < 0.001). In contrast, RA function was comparable between groups. In conclusion, LA contractility (active SV) increased in response to an increase in LA preload (LAVpre-A) up to a point beyond which LA contractility (active SV) decreased. Whether this is due to working of the LA at the descending limb of the Frank-Starling curve or mainly due to changes in afterload still remains unclear.

Three-dimensional echocardiography and cardiac magnetic resonance imaging in the screening of long-term survivors of childhood cancer after cardiotoxic therapy

The left ventricular (LV) volumes, ejection fraction (EF), and dyssynchrony indexes for the 16 and 12 cardiac segments (Tmsv16-SD and Tmsv12-SD, respectively) were analyzed among nonadult, anthracycline-exposed long-term survivors of childhood cancer and compared with those of healthy controls using conventional and real-time 3-dimensional echocardiography (RT-3DE) with cardiac magnetic resonance (CMR) imaging in a prospective, cross-sectional, single tertiary center setting. Seventy-one survivors and gender-, body surface area-, and age-matched healthy controls were studied by conventional echocardiography and RT-3DE. Fifty-eight of the 71 survivors underwent also CMR. The survivors were evaluated in 2 groups. Group I consisted of 63 exposed to anthracyclines and group II consisted of 8 also exposed to cardiac irradiation. By RT-3DE, the group I survivors had a lower LVEF (57% vs 60%, respectively, p = 0.003) and larger body surface area-indexed LV end-systolic volume (31 vs 28 ml/m(2), respectively, p = 0.001) than controls. The Tmsv16-SD was higher in group II than in I (1.93% vs 1.39%, respectively, p = 0.003). None of the survivors had an abnormal fractional shortening (<28%), but 10% had an LVEF <50% by RT-3DE. An LVEF <55% was detected in 45 of 58 (78%) of those imaged with CMR. In conclusion, RT-3DE seems to detect more abnormalities in cardiac function than conventional echocardiography following childhood cancer therapy. The LV dyssynchrony indexes derived from RT-3DE appear potentially useful in assessing the early signs of cardiotoxicity between anthracycline and cardiac irradiation exposed long-term survivors of childhood cancer.

Clinical application of three-dimensional echocardiography

Echocardiography is one of the most valuable diagnostic tools in cardiology. Technological advances in ultrasound, computer and electronics enables three-dimensional (3-D) imaging to be a clinically viable modality which has significant impact on diagnosis, management and interventional procedures. Since the inception of 3D fully-sampled matrix transthoracic and transesophageal technology it has enabled easier acquisition, immediate on-line display, and availability of on-line analysis for the left ventricle, right ventricle and mitral valve. The use of 3D TTE has mainly focused on mitral valve disease, left and right ventricular volume and functional analysis. As structural heart disease procedures become more prevalent, 3D TEE has become a requirement for preparation of the procedure, intra-procedural guidance as well as monitoring for complications and device function. We anticipate that there will be further software development, improvement in image quality and workflow.

Left atrial mechanics: echocardiographic assessment and clinical implications

The importance of the left atrium in cardiovascular performance has long been acknowledged. Quantitative assessment of left atrial (LA) function is laborious, requiring invasive pressure-volume loops and thus precluding its routine clinical use. In recent years, novel postprocessing imaging methodologies have emerged, providing a complementary approach for the assessment of the left atrium. Atrial strain and strain rate obtained using either Doppler tissue imaging or two-dimensional speckle-tracking echocardiography have proved to be feasible and reproducible techniques to evaluate LA mechanics. It is essential to fully understand the clinical applications, advantages, and limitations of LA strain and strain rate analysis. Furthermore, the technique's prognostic value and utility in therapeutic decisions also need further elucidation. The aim of this review is to provide a critical appraisal of LA mechanics. The authors describe the fundamental concepts and methodology of LA strain and strain rate analysis, the reference values reported with different imaging techniques, and the clinical implications.

Correlation-based discrimination between cardiac tissue and blood for segmentation of the left ventricle in 3-D echocardiographic images

For automated segmentation of 3-D echocardiographic images, incorporation of temporal information may be helpful. In this study, optimal settings for calculation of temporal cross-correlations between subsequent time frames were determined, to obtain the maximum cross-correlation (MCC) values that provided the best contrast between blood and cardiac tissue over the entire cardiac cycle. Both contrast and boundary gradient quality measures were assessed to optimize MCC values with respect to signal choice (radiofrequency or envelope data) and axial window size. Optimal MCC values were incorporated into a deformable model to automatically segment the left ventricular cavity. MCC values were tested against, and combined with, filtered, demodulated radiofrequency data. Results reveal that using envelope data in combination with a relatively small axial window (0.7-1.25 mm) at fine scale results in optimal contrast and boundary gradient between the two tissues over the entire cardiac cycle. Preliminary segmentation results indicate that incorporation of MCC values has additional value for automated segmentation of the left ventricle.

The Relationship between Left Atrial Volume and Ventricular Arrhythmias in the Patients with Dilated Cardiomyopathy

BACKGROUND

The present study aimed to investigate the relationship between Left Atrial Volume (LAV), a marker of diastolic dysfunction, and the frequency of malignant ventricular arrhythmia in the patients with left ventricular dysfunction and a previously implanted Implantable Cardioverter Defibrillator (ICD) device.

METHODS

This cross-sectional study was conducted on 32 patients with ischemic or idiopathic dilated cardiomyopathy, each having had an ICD device implanted at least 1 year beforehand. The ventricular arrhythmia episodes which were detected and stored by the device were retrieved and evaluated. In addition to routine echocardiographic measurements, all the patients had their LAV and LAV indexes calculated. After all, student's t-test, Mann-Whitney U test, and Pearson correlation were used to analyze the data. Besides, P value < 0.05 was considered as statistically significant.

RESULTS

This study was conducted on 4 female and 28 male patients with the mean age of 58.41 ± 9.97 years. Among the study patients, 21 had at least one previous myocardial infarction. In addition, 17 patients had experienced sustained VT or VF within the last year. No significant difference was found between the patients with and without malignant ventricular arrhythmias (sustained VT or VF) regarding LAV (17 patients with arrhythmia (68 + 23.39 mL) vs. 15 patients without arrhythmia (55.13 ± 20.41 mL); P = 0.100). However, the LAV index was significantly higher in the patients with arrhythmia compared to those without arrhythmia (39.27 ± 12.19 mL / m2 vs. 25.18 ± 7.45 mL / m2; P = 0.004). Both LAV (73.33 ± 17.64 mL and 57.52 ± 23.15 mL, respectively; P = 0.040) and LAV index (40.86 ± 8.47 mL / m2 and 28.20 ± 11.77 mL / m2, respectively; P = 0.010) were significantly greater in the patients with ICD shock therapy within the last year compared to the others. However, both groups were similar regarding Left Ventricular Volume (LVV), LVV index, and ejection fraction.

CONCLUSIONS

The study findings demonstrated that LAV and LAV index could be used in detecting the patients who are at high risk of malignant ventricular arrhythmias.

Comparison of three-dimensional speckle tracking echocardiography and two-dimensional echocardiography for evaluation of left atrial size and function in healthy volunteers (results from the MAGYAR-Healthy study)

OBJECTIVE

Noninvasive accurate assessment of left atrial (LA) size and function is an essential requirement in daily clinical practice. Real time three-dimensional (3D) echocardiography (RT3DE) with direct volumetric method has been found to be a highly accurate and reproducible noninvasive tool for the evaluation of LA dimensions and functional properties. Three-dimensional speckle tracking echocardiography (3DSTE) has just been introduced for volumetric assessments, which uses different, as called "block-matching" algorithm by strain analysis. This study was designed to compare two-dimensional (2D) echocardiography with 3DSTE for calculation of LA volumes and assessment of LA functional properties in healthy subjects.

METHODS

This study comprised of randomly selected 35 healthy subjects (40.9 ± 10.9 years, 20 men) in sinus rhythm, they all had undergone standard transthoracic 2D echocardiographic Doppler study extended with 3DSTE.

RESULTS

Two-dimensional echocardiography- and 3DSTE-derived minimum (Vmin ) and maximum (Vmax ) LA volumes and LA volume before atrial contraction (Vpre A ) did not differ significantly. Calculated functional LA properties were also compared. Good correlations were found between both techniques for Vmax (r = 0.93, P < 0.0001), Vmin (r = 0.62, P < 0.0001), and Vpre A (r = 0.74, P < 0.0001).

CONCLUSIONS

It may be stated that 3DSTE seems to be feasible in detection of cyclic changes in LA volumes and calculation of its functional properties is comparable to 2D echocardiography.

Left atrial volume and phasic function in clinically healthy dogs of 12 different breeds

The left atrium (LA) of the heart is a validated marker of clinical and subclinical cardiovascular disease. Since the LA is a three-dimensional structure, volume-based methods of chamber quantification might be more accurate than linear methods. The aims of this study were to establish the feasibility and reproducibility of biplane two-dimensional echocardiographic LA volume measurements and to provide reference ranges for LA volume and phasic function in adult dogs (n=237) without cardiovascular disease. The study also assessed the effects of bodyweight (BW), breed, sex, age and heart rate (HR) on LA volume and function. The biplane area-length method was used to calculate LA volumes from the left apical four- and two-chamber views. LA volume and function were correlated with body size and there were significant breed differences. For dogs of all sizes and breeds, LA maximal volume had a 95th percentile of 0.92 mL/kg. There was no correlation between age or sex and LA volume or LA reservoir function, but conduit function decreased and booster pump function increased with age. LA volume and function varied with HR. LA size was calculated using the biplane area-length method, with good reproducibility and little inter-observer variability. The reference ranges presented for LA volume and function in healthy dogs could be used to refine the diagnostic criteria for the assessment of LA enlargement and altered function by conventional echocardiography.

The assessment of atrial function in single ventricle hearts from birth to Fontan: a speckle-tracking study by using strain and strain rate

BACKGROUND

Single ventricle (SV) exercise performance is impaired and limited by reduced ventricular preload reserve. The atrium modulates ventricular filling, and enhancement of atrial compliance can increase cardiac performance. We aimed to study atrial mechanics in SV hearts across staged surgical palliation compared with healthy children by using novel speckle-tracking echocardiography techniques.

METHODS

A cross-sectional study of 81 patients with SV (1 day to 6.5 years) at 4 stages of surgical palliation (presurgery, 22; prebidirectional cavopulmonary anastomosis, 23; pre-Fontan, 22; post-Fontan, 14). The dominant atrium was assessed with speckle-tracking echocardiography for active (εact), conduit (εcon), and reservoir (εres) strain; strain rate (SR); and εact/εres ratio before each stage of surgical palliation. Findings were compared with the left atrium of 51 healthy children (1 day to 5.5 years).

RESULTS

Single ventricle atrial size was increased (P < .01), and atrial εres was decreased (P < .01) compared with healthy controls. SV atrial εcon (P < .01) and SRcon (P < .0001) was decreased, increased εact persisted (P < .05), and εact/εres was increased (P < .001) between surgical stages. Although the expected maturational trend of increasing εcon, decreasing εact, and εact/εres occurred in SV, they lagged behind healthy maturational changes (P < .0001).

CONCLUSION

Single ventricle atrium is dilated, has deceased compliance, decreased early diastolic emptying, and increased reliance on active atrial contraction for ventricular filling. This deviates from normal early childhood maturational changes and appears to parallel those of an atrium facing early ventricular diastolic dysfunction.

Effects of Age and Gender on Left Atrial Ejection Force and Volume from Real-Time Three-Dimensional Echocardiography

Introduction: This study was carried out to (i) provide the methodology for determining left atrial (LA) volume, emptying fraction and ejection force (LAEF), from real-time 3-dimensional echocardiography (RT3DE), and (ii) evaluate the effects of age and gender on LA volume and LAEF in a wide age range of healthy participants. Materials and Methods: RT3DE was performed in 102 healthy participants (age range, 20 to 80 years). From full-volume data sets, LA endocardial borders were automatically traced and LA volumes were determined. LAEF was calculated as 1/3×mitral annular area × (blood density) × (peak velocity of A wave)2 according to Newton’s law of motion and hydrodynamics; wherein the mitral annular area (MVA) is traced using RT3DE and A is the peak Doppler-derived blood velocity at atrial systole with the sample volume placed at the mitral annulus level. Results: ANOVA analysis revealed that LA volume indices were significantly correlated with age (r = 0.366, P <0.0001 for maximal volume index and r = 0.288, P <0.005 for minimal volume index). LAEF was also significantly positively correlated with age (r = 0.49, P <0.0001). The LA emptying fraction was maintained across ages. LA volume indices and LAEF did not differ significantly with gender. Conclusion: Our data can be used as normal reference values for LA volumes and LAEF. We have demonstrated that age is positively related to LA volume indices and LAEF, which suggests that age-dependent cut-off values should be considered in those with heart disease. Key words: Age, LA Ejection Force, RT3DE, Volume

Left Ventricular Systolic and Diastolic Function in Obstructive Sleep Apnea

Background—

Previous studies in obstructive sleep apnea (OSA) were limited by study cohorts with comorbidities that confound assessment of left ventricular (LV) systolic and diastolic function. We comprehensively evaluated LV function using 2-dimensional echocardiography (2DE), tissue Doppler imaging (TDI), and 3-dimensional echocardiography (3DE) in subjects moderate-severe OSA, who were compared with disease (patients with hypertension, no OSA) and healthy control subjects.

Methods and Results—

A total of 120 subjects (n=40 each of matched OSA, hypertension and healthy cohorts) underwent echocardiographic examination for the assessment of septal and posterior wall thickness, LV mass index, LV volumes and ejection fraction, mitral valve inflow indices (E, A), mitral annular velocity (S, E′), and left atrial volume index (LAVI). OSA subjects were treated with continuous positive airway pressure (mean duration of 26 weeks), after which the echocardiographic parameters were reassessed. Posterior wall thickness and LV mass index were significantly higher in OSA and hypertensive groups compared with healthy. Systolic S velocity was reduced in OSA and hypertensive compared with healthy control subjects ( P <0.05). Diastolic function (E/A, IVRT, and E/E′) was impaired in both OSA and hypertensive groups. On 3DE, mean LAVI was significantly greater in OSA and hypertensive compared with healthy. In OSA patients, continuous positive airway pressure therapy resulted in reduction of the posterior wall thickness ( P =0.02) and improvement in LV ejection fraction ( P <0.05), systolic S velocity ( P <0.05), and diastolic LV impairment parameters.

Conclusions—

Moderate to severe OSA causes structural and functional changes in LV function and are comparable to that seen in hypertension. These abnormalities significantly improve after CPAP therapy.

Case report: low circulating IGF-I levels due to Acid-Labile Subunit deficiency in adulthood are not associated with early development of atherosclerosis and impaired heart function

OBJECTIVE

Decreased insulin-like growth factor-I (IGF-I) levels in adults have been associated with an increased risk of ischemic heart disease and heart failure. It is currently unknown whether patients with low circulating IGF-I levels due to a homozygous acid-labile subunit (IGFALS) gene mutation also have increased risk of cardiovascular disease. Therefore, we evaluated atherosclerotic burden in a 27 year old male patient who was diagnosed with a homozygous IGFALS mutation and consequently had extremely low circulating IGF-I levels.

METHODS

Ten year's cardiovascular risk was calculated using the Framingham risk score. Presence of (subclinical) atherosclerosis was assessed using a 64-slice CT scan of the coronary arteries. Cardiac performance was measured by conventional echocardiographic measurements, three dimensional (3D)-echocardiography, and tissue deformation imaging.

RESULTS

Despite his extremely low circulating IGF-I levels due to Acid-Labile Subunit (ALS) deficiency, our patient had a low Framingham risk score and no signs of coronary atherosclerosis. Adjusted for physical height, cardiac performance was not impaired compared with healthy subjects.

CONCLUSION

The present case report does not lend support to routine cardiovascular screening in patients with extremely low circulating IGF-I levels due to a homozygous IGFALS mutation, when cardiovascular risk is low.

Left atrial dysfunction in chagas cardiomyopathy is more severe than in idiopathic dilated cardiomyopathy: a study with real-time three-dimensional echocardiography

BACKGROUND

Although there is anatomopathologic evidence of atrial involvement in Chagas cardiomyopathy (CCM), the impact in left atrial (LA) function is unknown. The aim of this study was to evaluate LA function in patients with CCM with real-time three-dimensional echocardiography (RT3DE) and to compare it with patients with idiopathic dilated cardiomyopathy (DCM).

METHODS

A total of 30 patients with CCM, 30 patients with DCM, and 20 normal subjects used as the control group were studied. With the use of RT3DE, we measured LA maximum (maxLAV), minimum, and pre-atrial contraction volumes and calculated total and active LA emptying fractions.

RESULTS

Left ventricular ejection fraction and mitral regurgitation were similar in both groups. MaxLAV/m(2) was larger in the CCM group than in the DCM group (76.9 ± 21.9 mL vs. 59.1 ± 26.0 mL; P < .01), and both were significantly larger than in the control group (P < .01). Total LA emptying fraction was lower in the CCM group than in the DCM group (0.30 ± 0.10 vs. 0.40 ± 0.12; P < .01), and both were lower than in the control group (P = .01). Active LA emptying fraction was also lower in the CCM group than in the DCM group (0.22 ± 0.09 vs. 0.28 ± 0.11; P < .01), and both were lower than in the control group (P = .01). The E/e' ratio was higher in the CCM group than in the DCM group (21 ± 10 vs. 15 ± 6; P < .01), and both were greater than in the control group (P < .01). In a multiple regression model, the E/e' ratio was the only independent predictor of a worsening active LA emptying fraction.

CONCLUSION

LA function is more compromised in patients with CCM than in patients with DCM. This finding indicates a more diffuse and severe myocardial impairment in Chagas disease that is probably related to increased left ventricular filling pressures and atrial myopathy.