Echocardiography algorithms to assess high left atrial pressure and grade diastolic function in preterm infants.

BACKGROUND: Relaxation, restoring forces, myocardial stiffness and atrial function determine left ventricular (LV) diastolic function. This study aims to provide a comprehensive assessment of diastolic function in preterm infants using conventional echocardiography and speckle tracking imaging and determine the diagnostic accuracy of various algorithms to detect high left atrial pressure (LAP). METHODS: Preterm infants received an echocardiogram 1 week after birth and diastolic reference values were derived from the outer percentiles of stable preterm infants. Impaired relaxation, LV stiffness and high LAP were defined by using algorithms where at least half of the parameters were outside the normal range. Diastolic function was graded using the 2016 American Society of Echocardiography algorithm and expanded with the EA ratio and left atrial strain. The diagnostic accuracy of various algorithms to detect high LAP was determined with sensitivity analysis. RESULTS: We studied 146 infants (59 stable) with a mean of 27(1) weeks gestation. Impaired relaxation, LV stiffness and high LAP were found in 8%, 7%, and 14% of infants. The patent ductus arteriosus was a contributing factor to high LAP and LV stiffness, not impaired relaxation. Diagnostic accuracy improved from 90% to 96% and sensitivity from 40% to 90% by adding left atrial strain to the 2016 algorithm. CONCLUSION: Various grades of diastolic dysfunction could be appreciated in preterm infants using a multi-parameter approach. Adding left atrial strain improved sensitivity to detect infants with high LAP.

Left ventricular vortex formation in preterm infants assessed by blood speckle imaging.

BACKGROUND: A vortex is a rotational fluid structure formed by shearing of fluid layers. It forms during diastole in the left ventricle (LV) and helps redirect flow to the LV outflow tract for ejection, optimizing energy conservation. The aim of this study was to demonstrate the feasibility of detecting and analyzing LV vortices using a new ultrasound technique known as blood speckle imaging (BSI). METHODS: Conventional and BSI parameters were acquired in preterm infants referred for echocardiography. BSI feasibility and reliability were explored using highest frequency settings and optimized Nyquist limits. Vortex area was determined by tracing the outer vortex ring at maximum area. Peak vortex formation time (PVFT) was determined at time of maximum vortex area relative to the R-wave, and vortex duration from frame-by-frame analysis of first appearance to vortex degradation. RESULTS: Left ventricle vortices were detected in 49 of the 50 preterm infants (weight 500-2020 g) with excellent intra- and inter-observer reliability. Mean vortex area indexed to LV area was 0.19 (0.08). Peak vortex formation time was at 87 (7)% of the cardiac cycle, and vortex duration lasted 13 (4)% of the cardiac cycle. Vortex area correlated positively with LV length, end-diastolic dimension, end-diastolic volume, mitral annular (R +0.42, +0.50, +0.47, +0.50, all P < 0.01), and transmitral Vti (R +0.37, P < 0.01). PVFT correlated negatively with E, EA, and Ee' (R -0.42, -0.47, -0.47, all P < 0.01). CONCLUSION: Left ventricle vortex formation can be analyzed with two-dimensional BSI and has the potential to complement existing parameters of cardiac health.

Left Ventricular Diastolic Dysfunction and Diastolic Heart Failure in Preterm Infants.

Diastolic dysfunction is primarily an echocardiographic diagnosis. Its clinical counterpart is diastolic heart failure, where the heart has difficulty to fill at normal pressure and the patient develops signs of pulmonary edema. Although diastolic dysfunction is common in adults, limited information is available in preterm infants. The aim of this study is to explore left ventricular diastolic dysfunction and diastolic heart failure in preterm infants and describe clinical manifestations in this population. This is a retrospective observational study in preterm infants < 30 weeks' gestation who received an echocardiography in the first 4 weeks after birth. Diastolic dysfunction was graded using a population-specific adapted version of the adult recommendations for the evaluation of left ventricular diastolic function by echocardiography. Left ventricular diastolic dysfunction was absent, indeterminate, and definite in 82%, 14%, and 4% of the 168 echocardiograms analyzed, and is associated with increased respiratory signs and respiratory deterioration at 48 h before echocardiogram. In seven infants, diastolic heart failure was diagnosed with both ultrasound and clinical signs. The cumulative risk of diastolic dysfunction increased with the increasing postnatal age and a patent ductus arteriosus. Evidence of left ventricular diastolic dysfunction on echocardiography is relatively common in preterm infants, while the left ventricular diastolic heart failure is less frequent. Prolonged exposure to volume load was the most common cause.

Right ventricle free wall mechanics in metabolic syndrome without type-2 diabetes: effects of a 3-month lifestyle intervention program.

BACKGROUND: Growing evidence demonstrates subtle left ventricular myocardial dysfunction in patients with metabolic syndrome (MetS), with central obesity, glucose intolerance and inflammation emerging as important contributors. Whether these results can be translated to the right ventricle (RV) is not yet fully elucidated. Furthermore, although lifestyle intervention favorably impacts MetS components and inflammatory biomarkers, its effect on RV myocardial function remains unknown today. METHODS: Thirty-nine MetS adults free of diabetes were enrolled in a three month lifestyle intervention program including diet and physical exercise, and compared with forty healthy controls. Blood biochemistry, echocardiography including tissue Doppler imaging (TDI), and vector velocity imaging of the RV free wall to assess global longitudinal strain (GLS) and strain rates (SR) were obtained at baseline and after the intervention. RESULTS: Compared with controls, MetS patients presented similar right atrial and RV morphology but reduced systolic (P = 0.04) and early diastolic (P = 0.02) velocities of the tricuspid annulus. They showed attenuated RV GLS (-21.4 ± 4.5 vs -25.7 ± 4.9%, P < 0.001) as well as early diastolic (P = 0.003) and systolic (P < 0.001) SR. Multiple regression analyses revealed log PAI-1 active, (P < 0.001), log adiponectin, (P = 0.01), LV mass indexed (P = 0.004) and central fat (P = 0.03) as independent predictors of RV GLS (R2 = 0.46, P < 0.001). Biological markers of MetS and inflammation as well as RV GLS (-21.8 ± 3.8 vs -24.3 ± 3.0%, P = 0.009) and systolic (P = 0.003) and early diastolic (P = 0.01) SR, but not TDI indexes, significantly improved after diet and exercise training, and vector velocity imaging data in MetS following the lifestyle intervention no longer differed from controls. CONCLUSIONS: MetS is associated with subtle impairments in both RV free wall diastolic and systolic myocardial function which could be partly related to central-obesity induced changes in pro- and anti-inflammatory cytokines and left ventricular remodeling. The favorable impact of healthy dieting and physical activity on RV free wall mechanics indicates that cellular and sub-cellular alterations responsible for the RV myocardial abnormalities are probably not permanent and modifiable throughout adequate interventional strategies. TRIAL REGISTRATION: American National Institutes of Health database NCT00917917.

Increased myocardial dysfunction, dyssynchrony, and epicardial fat across the lifespan in healthy males.

BACKGROUND: Evaluation of sensitive myocardial mechanics with speckle tracking echocardiography (STE) across the lifespan may reveal early indicators of cardiovascular disease (CVD) risk. Epicardial adipose tissue (EAT) and left ventricular (LV) myocardial dyssynchrony; subclinical risk-factors of CVD, are of particular clinical interest. However, the evolution of EAT and LV-dyssynchrony across the lifespan, and their influence on myocardial dysfunction remains unclear. We aimed to establish a profile of the healthy aging-heart using conventional, tissue-Doppler imaging (TDI) and speckle-tracking echocardiography (STE), while also exploring underlying contributions from EAT and LV-dyssynchrony towards LV myocardial mechanics, independent of blood biology. METHODS: Healthy males aged 19-94 years were recruited through University-wide advertisements in Victoria and New-South Wales, Australia. Following strict exclusion criteria, basic clinical and comprehensive echocardiographic profiles (conventional, TDI and STE) were established. LV-dyssynchrony was calculated from the maximum-delay of time-to-peak velocity/strain in the four LV-annulus sites (TDI), and six LV-segments (STE longitudinal and circumferential axes). Epicardial fat diameter was obtained from two-dimensional grey-scale images in the parasternal long-axis. Blood biological measures included glycemia, hsCRP, triglycerides, total cholesterol, high-density and low-density lipoprotein levels. RESULTS: Three groups of 15 were assigned to young (<40 years), middle (40-65 years), and older (>65) aged categories. Five participants were excluded from STE analyses due to inadequate image quality. Decreased longitudinal strain, increased circumferential apical strain and LV twist were age-related. Moreover, independent of blood biology, significant increases were observed across age categories for EAT (young: 2.5 ± 0.9 mm, middle: 3.9 ± 1.0 mm, older 5.7 ± 2.4 mm; p < 0.01), longitudinal STE-dyssynchrony (young: 42 ± 7.7 ms, middle: 58.8 ± 18.9 ms, older 88.6 ± 18.2 ms; p < 0.05), and circumferential-basal STE-dyssynchrony (young: 50.2 ± 20.5 ms, middle: 75.9 ± 20.6 ms, older 97.9 ± 20.2 ms; p < 0.05). These variables collectively explained 37% and 31% (p < 0.01) of longitudinal strain and LV twist, respectively. CONCLUSIONS: This study enabled comprehensive profiling of LV mechanics at different stages of aging using sensitive echocardiographic technology. Novel findings included increased epicardial fat, and both longitudinal and circumferential LV-dyssynchrony across the healthy age groups. These factors may be key underlying contributors to myocardial dysfunction during aging, and their recognition may promote an advanced understanding of early signs of cardiovascular disease.

Assessing Intracardiac Vortices with High Frame-Rate Echocardiography-Derived Blood Speckle Imaging in Newborns.

The left ventricle (LV) has a unique pattern of hemodynamic filling. During diastole, a rotational body or ring of fluid known as a vortex is formed due to the chiral geometry of the heart. A vortex is reported to have a role in conserving the kinetic energy of blood flow entering into the LV. Recent studies have shown that LV vortices may have prognostic value in describing diastolic function at rest in neonatal, pediatric, and adult populations, and may help with earlier subclinical intervention. However, the visualization and characterization of the vortex remain minimally explored. A number of imaging modalities have been utilized for visualizing and describing intracardiac blood flow patterns and vortex rings. In this article, a technique known as blood speckle imaging (BSI) is of particular interest. BSI is derived from high-frame rate color Doppler echocardiography and provides several advantages over other modalities. Namely, BSI is an inexpensive and noninvasive bedside tool that does not rely on contrast agents or extensive mathematical assumptions. This work presents a detailed step-by-step application of the BSI methodology used in our laboratory. The clinical utility of BSI is still in its early stages, but has shown promise within the pediatric and neonatal populations for describing diastolic function in volume-overloaded hearts. A secondary aim of this study is thus to discuss recent and future clinical work with this imaging technology.

The association between patterns of early respiratory disease and diastolic dysfunction in preterm infants.

BACKGROUND: This study aims to determine the association between clinical patterns of early respiratory disease and diastolic dysfunction in preterm infants. METHODS: Preterm infants <29 weeks' gestation underwent cardiac ultrasounds around day 7 and 14-21. Respiratory dysfunction patterns were classified as stable (ST), respiratory deterioration (RD) or early persistent respiratory dysfunction (EPRD) according to oxygen need. Diastolic dysfunction was diagnosed using a multi-parameter approach including left atrial strain (LASR) to help differentiate between cardiac or pulmonary pathophysiology. RESULTS: 98 infants (mean 27 weeks) were included. The prevalence of ST, RD and EPRD was 53%, 21% and 26% respectively. Diastolic dysfunction was more prevalent in the RD and EPRD groups with patent ductus arteriosus and significant growth restriction as risk factors. Not all infants with a PDA developed diastolic dysfunction. LASR was lower in the EPDR group. CONCLUSION: Respiratory dysfunction patterns are associated with diastolic dysfunction in preterm infants.

Cardiovascular risk of adipokines: a review.

Over the last two decades, the understanding of adipose tissue has undergone radical change. The perception has evolved from an inert energy storage tissue to that of an active endocrine organ. Adipose tissue releases a cluster of active molecules named adipokines. The severity of obesity-related diseases does not necessarily correlate with the extent of body fat accumulation but is closely related to body fat distribution, particularly to visceral localization. There is a distinction between the metabolic function of central obesity (visceral abdominal) and peripheral obesity (subcutaneous) in the production of adipokines. Visceral fat accumulation, linked with levels of some adipokines, induces chronic inflammation and metabolic disorders, including glucose intolerance, hyperlipidaemia, and arterial hypertension. Together, these conditions contribute to a diagnosis of metabolic syndrome, directly associated with the onset of cardiovascular disease. If it is well known that adipokines contribute to the inflammatory profile and appetite regulation, this review is novel in synthesising the current state of knowledge of the role of visceral adipose tissue and its secretion of adipokines in cardiovascular risk.

Effects of lifestyle intervention on left ventricular regional myocardial function in metabolic syndrome patients from the RESOLVE randomized trial.

AIMS: The purpose of our study was to determine the effect of lifestyle intervention on left ventricular (LV) regional myocardial function in patients with metabolic syndrome (MetS) and investigate the relationships of the changes in myocardial function to changes in epicardial adipose tissue (EAT), inflammatory profile and MetS components. METHODS: Eighty-seven MetS patients were enrolled in a 6month lifestyle intervention program based on dietary management and increased physical activity, and compared with 44 aged and sex-matched healthy controls. MetS individuals were allocated to different groups randomized (computer-generated randomization) on exercise modalities (high-intensity dominant resistance or aerobic training, and moderate-intensity of both modes). EAT was measured by transthoracic echocardiography and LV longitudinal strains and strain rates were obtained using vector velocity imaging. Blood chemistry allowed assessments of adipocytokines (TNF-α: tumor necrosis factor α, PAI active: active plasminogen activator inhibitor-1 and adiponectin) and glucose tolerance markers. RESULTS: Regardless of exercise training modalities, lifestyle intervention improved significantly LV strains and strain rates (p<0.001) as well as metabolic and inflammatory profiles. Stepwise multiple regression analyses revealed EAT (ß=0.73, p<0.01), log adiponectin (ß=-0.13, p<0.05) and log TNF-α (ß=0.15, p<0.05) as independent predictors of LV longitudinal strain (R(2)=0.74, p<0.001) while myocardial function improvement consecutive to lifestyle intervention was explained by EAT changes only (R(2)=0.54, p<0.001). CONCLUSION: The mechanisms through which regional myocardial function is impaired in MetS and improved consecutive to intervention involved EAT, possibly via paracrine effects of adipocytokines. EAT should be considered as a future therapeutic target of interest in the treatment of metabolic-related cardiac diseases.

Left ventricular myocardial dyssynchrony is already present in nondiabetic patients with metabolic syndrome.

The presence of left ventricular (LV) dyssynchrony in individuals with metabolic syndrome (MetS), a predictor of type 2 diabetes (T2D), lacks clarity. We compared LV dyssynchrony in MetS individuals with and without T2D, and healthy control subjects using speckle-tracking imaging echocardiography. Ninety-two MetS participants (64 without, 28 with T2D) and 40 control subjects underwent echocardiographic and clinical/biological analyses. LV-dyssynchrony in the longitudinal axis only was present in all MetS individuals, but was not further exacerbated by T2D. Strong associations were found with systemic inflammation, abdominal obesity, and LV mass. Investigations of myocardial dyssynchrony in the nondiabetic MetS stage might facilitate timely and more effective prevention.

Myocardial deformation and twist mechanics in adults with metabolic syndrome: impact of cumulative metabolic burden.

OBJECTIVE: The aim of the study is to characterize left ventricular (LV) myocardial mechanics in adults with metabolic syndrome (MetS), and elucidate the effects of multiple risk-factors on myocardial function using speckle tracking echocardiography (STE); a more sensitive method than conventional echocardiography for detecting subclinical myocardial dysfunction. DESIGN AND METHODS: Cross-sectional analyses of 92 adults (50-70 years) with MetS, and 50 healthy controls included conventional echocardiography, blood biochemistry, and STE-derived myocardial longitudinal, circumferential, and twist mechanics. RESULTS: Using conventional measures, MetS participants revealed LV hypertrophy and reduced diastolic function compared with controls, while systolic function was preserved. From STE, MetS participants showed attenuated longitudinal strain (-16.8% ± 2.8% vs. -20.6% ± 2.7%), and both diastolic (1.1 ± 0.2 vs. 1.4 ± 0.3 s s(-1) ) and systolic (-1.0 ± 0.1 vs. -1.2 ± 0.2 s s(-1) ) strain rate (SR). Circumferential strain, SR, and twist mechanics did not differ. Participants with the highest number of MetS factors or diabetes demonstrated the greatest reduction in longitudinal strain and SR. Abdominal obesity, TNF-α, HbA1c , and systolic dyssynchrony explained 48% of impairment in longitudinal strain. CONCLUSIONS: Impaired longitudinal myocardial diastolic and systolic function, but preserved circumferential function and twist mechanics were found in MetS participants, indicative of altered subendocardial function. This dysfunction was best predicted by abdominal obesity, inflammation, glucose-intolerance, and systolic dyssynchrony.