Systolic and Diastolic Myocardial Mechanics in Patients with Cardiac Disease and Preserved Ejection Fraction: Impact of Left Ventricular Filling Pressure

Orbit symmetry breaking in MXene implements enhanced soft bioelectronic implants

Bioelectronic implants featuring soft mechanics, excellent biocompatibility, and outstanding electrical performance hold promising potential to revolutionize implantable technology. These biomedical implants can record electrophysiological signals and execute direct therapeutic interventions within internal organs, offering transformative potential in the diagnosis, monitoring, and treatment of various pathological conditions. However, challenges remain in improving excessive impedance at the bioelectronic-tissue interface and thus the efficacy of electrophysiological signaling and intervention. Here, we devise orbit symmetry breaking in MXene (a low-cost scalability, biocompatible, and conductive two dimensionally layered material, which we refer to as OBXene), which exhibits low bioelectronic-tissue impedance, originating from the out-of-plane charge transfer. Furthermore, the Schottky-induced piezoelectricity stemming from the asymmetric orbital configuration of OBXene facilitates interlayered charge transport in the device. We report an OBXene-based cardiac patch applied on the left ventricular epicardium of both rodent and porcine models to enable spatiotemporal epicardium mapping and pacing while coupling the wireless and battery-free operation for long-term real-time recording and closed-loop stimulation.

The assessment of left ventricular diastolic function: guidance and recommendations from the British Society of Echocardiography

Impairment of left ventricular (LV) diastolic function is common amongst those with left heart disease and is associated with significant morbidity. Given that, in simple terms, the ventricle can only eject the volume with which it fills and that approximately one half of hospitalisations for heart failure (HF) are in those with normal/'preserved' left ventricular ejection fraction (HFpEF) (Bianco et al. in JACC Cardiovasc Imaging. 13:258-271, 2020. 10.1016/j.jcmg.2018.12.035), where abnormalities of ventricular filling are the cause of symptoms, it is clear that the assessment of left ventricular diastolic function (LVDF) is crucial for understanding global cardiac function and for identifying the wider effects of disease processes. Invasive methods of measuring LV relaxation and filling pressures are considered the gold-standard for investigating diastolic function. However, the high temporal resolution of trans-thoracic echocardiography (TTE) with widely validated and reproducible measures available at the patient's bedside and without the need for invasive procedures involving ionising radiation have established echocardiography as the primary imaging modality. The comprehensive assessment of LVDF is therefore a fundamental element of the standard TTE (Robinson et al. in Echo Res Pract7:G59-G93, 2020. 10.1530/ERP-20-0026). However, the echocardiographic assessment of diastolic function is complex. In the broadest and most basic terms, ventricular diastole comprises an early filling phase when blood is drawn, by suction, into the ventricle as it rapidly recoils and lengthens following the preceding systolic contraction and shortening. This is followed in late diastole by distension of the compliant LV when atrial contraction actively contributes to ventricular filling. When LVDF is normal, ventricular filling is achieved at low pressure both at rest and during exertion. However, this basic description merely summarises the complex physiology that enables the diastolic process and defines it according to the mechanical method by which the ventricles fill, overlooking the myocardial function, properties of chamber compliance and pressure differentials that determine the capacity for LV filling. Unlike ventricular systolic function where single parameters are utilised to define myocardial performance (LV ejection fraction (LVEF) and Global Longitudinal Strain (GLS)), the assessment of diastolic function relies on the interpretation of multiple myocardial and blood-flow velocity parameters, along with left atrial (LA) size and function, in order to diagnose the presence and degree of impairment. The echocardiographic assessment of diastolic function is therefore multifaceted and complex, requiring an algorithmic approach that incorporates parameters of myocardial relaxation/recoil, chamber compliance and function under variable loading conditions and the intra-cavity pressures under which these processes occur. This guideline outlines a structured approach to the assessment of diastolic function and includes recommendations for the assessment of LV relaxation and filling pressures. Non-routine echocardiographic measures are described alongside guidance for application in specific circumstances. Provocative methods for revealing increased filling pressure on exertion are described and novel and emerging modalities considered. For rapid access to the core recommendations of the diastolic guideline, a quick-reference guide (additional file 1) accompanies the main guideline document. This describes in very brief detail the diastolic investigation in each patient group and includes all algorithms and core reference tables.

Correlation of left ventricular longitudinal strain and E/e' ratio in primary hypertension patients

Objectives: The aim of this study is to explore and compare the relationships of both global longitudinal strain (GLS) and strain (SR) with E/e' ratio in a population of asymptomatic patients with systemic hypertension.Methods: Retrospectively included 210 cases of essential hypertension patients. Dynamic images were analyzed for left ventricular myocardial systolic global longitudinal strain (GLS), left ventricular longitudinal peak systolic strain rate (SRs), early diastolic peak strain rate (SRe), late diastolic peak strain rate (SRa). According to the 2012 baseline E/e' ratio, the population was divided into three groups, group A (E/e'<8), group B (8 ≤ E/e'≤14), and group C (E/e'>14).Results: Systolic function parameters left ventricular ejection fraction (LVEF) remained at normal rage and no different, but patients with elevated E/e' ratio had significantly lower GLS, lower early diastolic strain rate(SRe), lower ratio of early diastolic strain rate to late diastolic strain rate (SRe/a) and higher E/SRe. Positive relationships were observed between GLS, E/SRe and E/e' ratio, inverse relationships were observed between SRe, SRe/a and E/e' ratio. E/SRe >0.73 had a sensitivity of 87.7% and a specificity of 38.2% for predicting an elevated E/e' ratio (E/e'>14). In multivariable analysis, IVS-e' <7 cm/s showed almost 2.5-fold increased risk for decreased GLS (OR 2.48[95% CI 1.36-4.53]; p = 003).Conclusions: Our current study demonstrated that hypertensive patients with preserved LVEF and elevated E/e' ratio have systolic and diastolic abnormalities in longitudinal directions as detected by speckle imaging. E/SRe correlates well with E/e' and predicted elevated left ventricular filling pressure.

Evaluation of Left Ventricular Diastolic Function by 2-D Speckle Tracking Echocardiography in Patients with Connective Tissue Disease-Associated Pulmonary Artery Hypertension

The purpose of this study was to evaluate the role of 2-D speckle tracking imaging in assessing left ventricular diastolic function in patients with connective tissue disease (CTD). A total of 98 CTD patients and 32 healthy controls were prospectively recruited. Early (E) and late (A) diastolic velocities of the transmitral flow were measured by pulsed Doppler echocardiography. Peak early diastolic myocardial velocity (E') was calculated on tissue Doppler echocardiography. The longitudinal strain rate (SR) was calculated as the average of three apical views, while circumferential and radial SRs were measured in three short-axis views. Pulmonary arterial hypertension (PAH) was defined as systolic pulmonary arterial pressure (sPAP) >36 mm Hg. Compared with the control group, CTD patients exhibited significant impairment of left ventricular diastolic function, manifested as lower global SR during early diastole (SRe) in the longitudinal deformation and higher E/SRe in both longitudinal and radial deformation. CTD-PAH patients had significantly lower SRe and higher E/SRe values in both the longitudinal and radial deformation compared with the patients with CTD without PAH. Pearson's correlation analysis revealed that sPAP levels correlated positively with E/E', longitudinal E/SRe, circumferential E/SRe and radial SRe, and it correlated negatively with septal E' and radial E/SRe. Receiver operating characteristic curve analysis suggested that E/E', longitudinal E/SRe and radial SRe could be used to predict PAH. The present study indicates that 2-D speckle tracking imaging is a useful method for evaluation of left ventricular diastolic function, and these derived parameters can serve as good predictors of PAH, but it may not be superior to the commonly used E/E' in CTD patients.

Usefulness and clinical relevance of left ventricular global longitudinal systolic strain in patients with heart failure with preserved ejection fraction

In recent years, several studies have shown the usefulness and clinical relevance of left ventricular global longitudinal systolic strain (GLS) in different cardiovascular diseases. In line with this, the role of GLS in patients with heart failure with preserved ejection fraction (HFpEF) has achieved great importance in this predominant form of heart failure in the last years. In this regard, GLS has shown to be not only a sensitive parameter to detect subtle myocardial abnormalities but also a parameter of clinical and prognostic relevance in patients with HFpEF. In this review, we analyze the current evidence concerning the clinical relevance of GLS in patients with HFpEF and we discuss the potential usefulness of GLS in this complex and heterogeneous condition for which so far no effective therapy exists.

Cardiac mechanics in heart failure with preserved ejection fraction

Heart failure with preserved ejection fraction (HFpEF) is a complex clinical entity associated with significant morbidity and mortality. Common comorbidities including hypertension, coronary artery disease, diabetes, chronic kidney disease, obesity, and increasing age predispose to preclinical diastolic dysfunction that often progresses to frank HFpEF. Clinical HFpEF is typically associated with some degree of diastolic dysfunction, but can occur in the absence of many conventional diastolic dysfunction indices. The exact biologic links between risk factors, structural changes, and clinical manifestations are not clearly apparent. Innovative approaches including deformation imaging have enabled deeper understanding of HFpEF cardiac mechanics beyond conventional metrics. Furthermore, predictive analytics through data-driven platforms have allowed for a deeper understanding of HFpEF phenotypes. This review focuses on the changes in cardiac mechanics that occur through preclinical myocardial dysfunction to clinically apparent HFpEF.

Real time mitochondrial dimension measurements

Mitochondrial volume is correlated with cell function and internal cell processes. Changes in mitochondrial volume were associated with advanced states of cardiac disease. Thus, measurements of mitochondrial dimension deformations are important to the understanding of cell function and its deterioration. Existing methods either allow measurements of the volume of isolated mitochondria, which are an inferior model to that of isolated cells, or they allow short time measurements that are toxic to the cells. Recent studies have discovered that mitochondrial deformation along a given cell axis can be measured by using the Fourier transformation on the variation in transmitted light intensity induced by the periodic lattice of myofilaments alternating with mitochondrial rows. However, this method was used only offline and in a line scan mode, making it impossible to measure both axes. We designed an open source program in LabVIEW to take advantage of the transmitted light diffraction technique and quantify mitochondrial two dimension (2D) deformation in cardiomyocytes, in situ in real time for long periods (more than several seconds). We validated the program on synthetic and on experimental images from rabbit and rat ventricular myocytes. The program can analyze offline and real time simultaneous 2D mitochondrial deformation dynamics as well as also sarcomere length dynamics. Moreover, the program can accurately analyze images acquired from different cameras. Quantification of mitochondrial 2D deformations is a powerful tool for exploring cell biophysics and bioenergetics mechanisms and will lay the foundation for a future clinical tool for quantifying mitochondrial volume changes associated with different cardiac diseases.

Left ventricular strain and twisting in heart failure with preserved ejection fraction: an updated review

Despite the high prevalence of the patients with heart failure with preserved ejection fraction (HFpEF), our knowledge about this entity, from diagnostic tools to therapeutic approach, is still not well established. The evaluation of patients with HFpEF is mainly based on echocardiography, as the most widely accepted tool in cardiac imaging. Identification of left ventricular (LV) diastolic dysfunction has long been considered as the only responsible for HFpEF, and its evaluation is still "sine qua non" of HFpEF diagnostics. However, one should be aware of the fact that identifying cardiac dysfunction in HFpEF might be very challenging and often needs more complex evaluation of cardiac structure and function. New echocardiographic modalities such as 2D and 3D speckle tracking imaging could help in the diagnosis of HFpEF and provide further information regarding LV function and mechanics. Early diagnosis, medical management, and adequate monitoring of HFpEF patients are prerequisites of modern medical treatment. New healthcare approaches require individualized patient care, which is why clinicians should have all clinical, laboratory, and diagnostic data before making final decisions about the treatment of any patients. This is particularly important for HFpEF that often remains undiagnosed for quite a long time, which further prolongs the beginning of adequate treatment and brings into question outcome of these patients. The aim of this article is to provide the overview of the main principles of LV mechanics and summarize recent data regarding LV strain in patients with HFpEF.

Interpreting measurements of cardiac function using vendor-independent speckle tracking echocardiography in children: a prospective, blinded comparison with catheter-derived measurements

BACKGROUND

Adult studies demonstrate that echocardiographic measurements of cardiac function using speckle tracking correlate with invasive measurements, but such data in the pediatric population are sparse. Our aim was to compare speckle-derived measures of cardiac function to measurements routinely obtained by cardiac catheterization in children.

METHODS

Echocardiograms were performed on the day of cardiac catheterization. Using Tomtec 2D Cardiac Performance Analysis, longitudinal strain (LS), longitudinal strain rate (LSR), early diastolic LSR, and ejection fraction (EF) for the right and left ventricle (RV and LV) were calculated via speckle tracking. Global LS and LSR were calculated for the LV. These results were compared to cardiac index, maximum ventricular dp/dt (max dp/dt), ventricular end-diastolic pressure (EDP), and pulmonary capillary wedge pressure (PCWP) obtained by fluid-filled catheters. A blinded observer performed all echo measurements.

RESULTS

Fifty studies were performed on 28 patients ages 4 months to 20 years old. Their diagnoses included cardiac transplant (48 studies), repaired AV septal defect (1), and dilated cardiomyopathy (1). RVEDP ranged from 2 to 22 mm Hg (median=6) and PCWP ranged from 6 to 32 mmHg (median 10). LV global LS and LV 2-chamber LSR by speckle-tracking negatively correlated with LV max dp/dt (LV global LS R=-.83, P=.001; LV 2-chamber LSR R=-.69, P=.009). RV LS weakly correlated with max dp/dt (R=.363, P=.002). Early diastolic strain rate did not correlate with EDP in either ventricle.

CONCLUSION

Speckle-derived measurements of function in the LV have stronger correlation than the RV to catheter-derived measures. LV global LS has the strongest correlation with invasive function measures in children.

Correlation of Global Strain Rate and Left Ventricular Filling Pressure in Patients with Coronary Artery Disease: A 2-D Speckle-Tracking Study

The aim of the present study was to evaluate the role of 2-D speckle-tracking imaging in the prediction of left ventricular filling pressure in patients with coronary artery disease (CAD) and normal left ventricular ejection fraction (LVEF). Eighty-four patients with CAD and 30 healthy controls were recruited prospectively. The longitudinal strain rate (SR) curves were determined in three apical views of the left ventricle long axis. Circumferential and radial SR curves were determined in three short-axis views. Left ventricular end-diastolic pressure (LVEDP) was invasively obtained by left heart catheterization. Compared with the 30 controls, the patients with CAD had significantly lower global SR during early diastole (SRe) and higher E/SRe in three directions of myocardial deformation. CAD patients with elevated LVEDP had significantly lower SRe and higher E/SRe of three deformations. Pearson's correlation analysis revealed that LVEDP correlated positively with E/E' ratio, radial SRe and longitudinal and circumferential E/SRe. LVEDP correlated negatively with longitudinal and circumferential SRe and radial E/SRe. Receiver operating characteristic curve analysis revealed that these SR indexes predicted elevated LVEDP (areas under the curve: longitudinal E/SRe = 0.74, circumferential E/SRe = 0.74, circumferential SRe = 0.70, longitudinal SRe = 0.69, radial E/SRe = 0.68, radial SRe = 0.65), but neither was superior to the tissue Doppler imaging index E/E' (area under the curve = 0.84). The present study indicates that 2-D speckle-tracking imaging is a practical method for evaluating LV filling pressure, but it might not provide additional advantages compared with E/E' in CAD patients.

Evaluation of Left Ventricular Diastolic Dysfunction with Early Systolic Dysfunction Using Two-Dimensional Speckle Tracking Echocardiography in Canine Heart Failure Model

BACKGROUND

This study evaluated the role of two-dimensional speckle tracking echocardiography (2DSTE) for predicting left ventricular (LV) diastolic dysfunction in pacing-induced canine heart failure.

METHODS

Pacing systems were implanted in 8 adult mongrel dogs, and continuous rapid right ventricular pacing (RVP, 240 beats/min) was maintained for 2 weeks. The obtained measurements from 2DSTE included global strain rate during early diastole (SRe) and during late diastole (SRa) in the longitudinal (L-SRe, L-SRa), circumferential (C-SRe, C-SRa), and radial directions (R-SRe, R-SRa). Changes in heart morphology were observed by light microscopy and transmission electron microscopy at 2 weeks.

RESULTS

The onset of LV diastolic dysfunction with early systolic dysfunction occurred 3 days after RVP initiation. Most of the strain rate imaging indices were altered at 1 or 3 days after RVP onset and continued to worsen until heart failure developed. Light and transmission electron microscopy showed myocardial vacuolar degeneration and mitochondrial swelling in the left ventricular at 2 weeks after RVP onset. Pearson's correlation analysis revealed that parameters of conventional echocardiography and 2DSTE showed moderate correlation with LV pressure parameters, including E/Esep' (r = 0.58, P < 0.01), L-SRe (r = -0.58, P < 0.01), E/L-SRe (r = 0.65, P < 0.01), and R-SRe (r = 0.53, P < 0.01). ROC curves analysis showed that these indices of conventional echocardiography and strain rate imaging could effectively predict LV diastolic dysfunction (area under the curve: E/Esep' 0.78; L-SRe 0.84; E/L-SRe 0.80; R-SRe 0.80).

CONCLUSION

2DSTE was a sensitive and accurate technique that could be used for predicting LV diastolic dysfunction in canine heart failure model.

Left ventricular diastolic function and dysfunction: Central role of echocardiography

Comprehensive and precise assessment of left ventricular (LV) systolic and diastolic function is necessary to establish, or exclude, heart failure as a cause or component of dyspnea. Echocardiography with Doppler readily assesses LV diastolic function; advantages include that echocardiography is non-invasive, does not require radiation, is portable, rapid, readily available, and in competent hands, can provide an accurate and comprehensive assessment of LV systolic and diastolic function. Correct assessment of LV diastolic function is relevant in patients with both depressed and preserved LV ejection fraction (EF ≥ 50%, and < 50%, respectively). Tissue Doppler (TD) imaging has been useful in demonstrating impaired LV relaxation in the setting of preserved LVEF, which, in the setting of increased cardiac volume, can result in elevated LV filling pressures, and dyspnea due to diastolic heart failure. TD imaging is not always critical in patients with depressed LVEF, since such patients by definition have impaired LV relaxation, and thus significant increases in volume will result in increases in LV filling pressure due to impaired LV compliance. Thus, in depressed LVEF, transmitral flow velocities (E and A, and E/A) and deceleration time, pulmonary venous Doppler, left atrial volume, and pulmonary artery (PA) pressures suffice for the accurate assessment of LV filling pressures. Overall, diastolic assessment by echo-Doppler can be readily achieved in by using a comprehensive diastolic assessment—incorporating many 2-dimensional, conventional and tissue Doppler variables—as opposed to relying on any single, diastolic parameter, which can lead to errors.

Comparative study of changes in energy metabolism in rat cardiomyocytes in postinfarction cardiosclerosis and diabetes mellitus

Cardiomyocyte energy metabolism in experimental unfolding postinfarction cardiosclerosis and diabetes mellitus was studied. Postinfarction cardiosclerosis formed 6 weeks after coronary artery occlusion. Diabetes mellitus was induced by intraperitoneal injection of streptozotocin (60 mg/kg). The rate of oxygen consumption in postinfarction cardiosclerosis and diabetes increased by 3.4 and 4.2 times, respectively. Stimulation of mitochondrial respiration (ATP, palmitic acid) significantly increased oxygen consumption in animals with postinfarction cardiosclerosis and significantly reduced this process in diabetes. The content of LDH and SDH in the myocardium of animals with diabetes and postinfarction cardiosclerosis was significantly below the control. Hence, the development of postinfarction cardiosclerosis and diabetes mellitus were characterized by reduced generation of ATP in anaerobic and aerobic pathways and oxidative phosphorylation in cardiomyocytes.

Left ventricular twist and ventricular-arterial coupling in hypertensive patients

BACKGROUND

Left ventricular (LV) twist is usually influenced by LV hypertrophy resulting from hypertension or vascular stiffness. Vascular stiffness would increase arterial elastance (Ea), whereas LV end-systolic stiffness (Ees) could be influenced by LV hypertrophy. Therefore, in hypertensive patients, we assessed the extent to which ventricular-arterial coupling (VAC; Ea/Ees) affects LV twist, which may be a compensatory mechanism for systolic dysfunction.

METHODS

Hypertensive patients (n = 128) and healthy controls (n = 40) underwent conventional and speckle tracking echocardiography including LV twist. Ea and Ees were estimated noninvasively by echocardiography. Patients were divided into 3 tertiles according to the twist angle. Univariate and multivariate regression analyses were performed to test the influence of VAC on twist.

RESULTS

Patients in the lowest LV twist tertile had larger LV end-systolic volume, lower ejection fraction, lesser mid-wall fractional shortening (MWFS), and higher LV mass index (LVMI), compared to those with the highest tertile. They showed the lower septal tissue Doppler velocity, and global longitudinal and circumferential strain. With regard to VAC, Ea was similar among 3 groups, but Ees was significantly decreased in patient with lower tertile, resulting in increased VAC (1.1 ± 0.2 vs. 0.9 ± 0.1 vs. 0.7 ± 0.1, P < 0.001). While LV twist showed significant correlations with Ees, MWFS, and LVMI, VAC (β = -14.92, P < 0.001) was most associated with twist in a multivariate analysis.

CONCLUSIONS

LV twist was significantly associated with VAC in accordance with LV function; LV twist and VAC decreased progressively as LV systolic function deteriorated, while being enhanced during the well-compensated phase.

Echocardiographic predictors of exercise capacity and mortality in chronic obstructive pulmonary disease

BACKGROUND

Chronic obstructive pulmonary disease (COPD) reduces exercise capacity, but lung function parameters do not fully explain functional class and lung-heart interaction could be the explanation. We evaluated echocardiographic predictors of mortality and six minutes walking distance (6MWD), a marker for quality of life and mortality in COPD.

METHODS

Ninety COPD patients (GOLD criteria) were evaluated by body plethysmography, 6MWD and advanced echocardiography parameters (pulsed wave tissue Doppler and speckle tracking).

RESULTS

Mean 6MWD was 403 (± 113) meters. All 90 subjects had preserved left ventricular (LV) ejection fraction 64.3% ± 8.6%. Stroke volume decreased while heart rate increased with COPD severity and hyperinflation. In 66% of patients, some degree of diastolic dysfunction was present. Mitral tissue Doppler data in COPD could be interpreted as a sign of low LV preload and not necessarily an intrinsic impairment in LV relaxation/compliance. Tricuspid regurgitation (TR) increased with COPD severity and hyperinflation. Age (p < 0.001), BMI (p < 0.001), DLCO SB (p < 0.001) and TR (p 0.005) were independent predictors of 6MWD and a multivariable model incorporating heart function parameters (adjusted r2 = .511) compared well to a model with lung function parameters alone (adjusted r2 = .475). LV global longitudinal strain (p = 0.034) was the only independent predictor of mortality among all baseline, body plethysmographic and echocardiographic variables.

CONCLUSIONS

Among subjects with moderate to severe COPD and normal LVEF, GLS independently predicted all-cause mortality. Exercise tolerance correlated with standard lung function parameters only in univariate models; in subsequent models including echocardiographic parameters, longer 6MWD correlated independently with milder TR, better DLCO SB, younger age and lower BMI. We extended the evidence on COPD affecting cardiac chamber volumes, LV preload, heart rate, as well as systolic and diastolic function. Our results highlight lung-heart interaction and the necessity of cardiac evaluation in COPD.

Usefulness of speckle tracking echocardiography in hypertensive crisis and the effect of medical treatment

The acute impact of hypertensive crisis, and changes after treatment, on left ventricular (LV) systolic and diastolic function using comprehensive echocardiography, including speckle tracking, has not been well characterized. Thirty consecutive patients admitted to the hospital from the emergency room with hypertensive crisis underwent Doppler echocardiography at baseline and after blood pressure optimization. The mean age of the patients was 54 ± 13 years, with 19 men (63%). The most common presenting symptoms included dyspnea (70%), chest pain (43%), and altered mental status (13%). Mean systolic and diastolic blood pressures at presentation were 198 ± 12 and 122 ± 12 mm Hg, decreasing to 143 ± 15 and 77 ± 12 mm Hg (p <0.001 for both) after treatment. There was no significant change in LV ejection fraction between baseline and follow-up (48 ± 18% vs 46 ± 18%, p = 0.50); however, global longitudinal LV systolic strain (-10 ± 4% to -12 ± 4%, p = 0.01) and global systolic strain rate (-1.0 ± 0.4 vs -1.4 ± 0.6 s(-1), p = 0.01) significantly improved. Mean global early diastolic strain (-7.2 ± 4.0% to -9.4 ± 2.9%, p = 0.004) and early diastolic strain rate (0.3 ± 0.2 to 0.5 ± 0.4 s(-1), p = 0.05) also improved after treatment. On multivariate analysis, the independent predictors of LV longitudinal strain at follow-up were LV ejection fraction (p <0.001), heart rate (p = 0.005), systolic blood pressure (p = 0.04), and left atrial volume index (p = 0.05). In conclusion, as opposed to LV ejection fraction, LV systolic strain and strain rate were depressed during hypertensive crisis and significantly improved after medical treatment. LV diastolic function, assessed using conventional and speckle-tracking parameters, was also depressed and significantly improved after treatment.

Two- and three-dimensional speckle tracking echocardiography: clinical applications and future directions

Two-dimensional speckle tracking echocardiography (2D STE) is a novel technique of cardiac imaging for quantifying complex cardiac motion based on frame-to-frame tracking of ultrasonic speckles in gray scale 2D images. Two-dimensional STE is a relatively angle independent technology that can measure global and regional strain, strain rate, displacement, and velocity in longitudinal, radial, and circumferential directions. It can also quantify rotational movements such as rotation, twist, and torsion of the myocardium. Two-dimensional STE has been validated against hemodynamics, tissue Doppler, tagged magnetic resonance imaging, and sonomicrometry studies. Two-dimensional STE has been found clinically useful in the assessment of cardiac systolic and diastolic function as well as providing new insights in deciphering cardiac physiology and mechanics in cardiomyopathies, and identifying early subclinical changes in various pathologies. A large number of studies have evaluated the role of 2D STE in predicting response to cardiac resynchronization therapy in patients with severe heart failure. However, the clinical utility of 2D STE in the above mentioned conditions remains controversial because of conflicting reports from different studies. Emerging areas of application include prediction of rejection in heart transplant patients, early detection of cardiotoxicity in patients receiving chemotherapy for cancer, and effect of intracoronary injection of bone marrow stem cells on left ventricular function in patients with acute myocardial infarction. The emerging technique of three-dimensional STE may further extend its clinical usefulness.

Myocardial systolic and diastolic performance derived by 2-dimensional speckle tracking echocardiography in heart failure with normal left ventricular ejection fraction

BACKGROUND

The aim of this study was to investigate the myocardial systolic and diastolic performance of the left ventricle (LV) in patients with heart failure with normal LV ejection fraction (HFNEF) through novel LV myocardial indices, which assess the systolic and diastolic function of the whole myocardium of the LV.

METHODS AND RESULTS

LV myocardial systolic and diastolic performance were assessed as the average value of peak systolic strain and peak early-diastolic strain rate, respectively, in longitudinal, circumferential, and radial directions from all LV segments using 2-dimensional speckle-tracking echocardiography. We studied patients with HFNEF and a control group consisting of asymptomatic subjects with LV diastolic dysfunction of similar age, sex, and LV ejection fraction. A total of 322 patients were included (92 with HFNEF and 230 with asymptomatic LV diastolic dysfunction). Myocardial systolic and diastolic LV performance were significantly lower in HFNEF (20.13±6.02% and 1.14±0.27 s(-1)) than in patients with asymptomatic LV diastolic dysfunction (25.33±6.06% and 1.37±0.33 s(-1), respectively; all P<0.0001). In addition, patients with HFNEF with low systolic and diastolic LV myocardial performance had significantly higher LV filling pressures (17.1±6.6 and 17.6±6.3 versus 12.0±5.1 and 11.7±4.7, respectively; all P<0.001) and lower cardiac output (4.8±1.0 L/min and 4.9±1.1 L/min versus 5.7±1.2 L/min and 5.8±1.1 L/min, respectively; all P<0.001) than patients with normal LV myocardial performance. In relation to these findings, the symptomatic status (ie, New York Heart Association functional class) was significantly altered in those patients with low systolic and diastolic LV myocardial performance.

CONCLUSIONS

In patients with HFNEF, both systolic and diastolic LV myocardial performance are impaired, which is associated with increased LV filling pressures, decreased cardiac output, and worse New York Heart Association functional class. Therefore, the measurement of these myocardial parameters could be of great importance in HFNEF because these echocardiographic indices assess the multidirectional function of the whole myocardium of the LV, thereby allowing detection of an alteration of the global function of the LV which is associated with a worse symptomatic status in these patients.

A novel global strain diastolic index correlates with plasma NT-proBNP levels in asymptomatic hypertensive patients with preserved left ventricular ejection fraction

BACKGROUND

The strain imaging diastolic index (SI-DI) was reported to be a sensitive marker of regional left ventricular (LV) delayed relaxation induced by ischemia. However, the clinical usefulness of the global SI-DI has not been evaluated. N-terminal pro-brain natriuretic peptide (NT-proBNP) is a sensitive biomarker for the detection of asymptomatic diastolic LV dysfunction. This study investigated the ability of a novel parameter, the global SI-DI, obtained using 2D speckle tracking imaging (2DSI) to correlate with the plasma NT-proBNP levels in asymptomatic hypertensive patients with preserved LV ejection fraction.

METHODS

We performed 2D echocardiography and 2DSI in 83 asymptomatic hypertensive patients with preserved ejection fraction (>45 %) and in 37 control subjects. In 2DSI, the LV longitudinal peak strain and the SI-DI of 18 LV segments were measured. NT-proBNP was measured in all subjects. The data were compared between hypertensive patients and normal controls.

RESULTS

The average peak strain and global SI-DI of 18 LV segments were significantly reduced in hypertensive patients compared with control subjects (P < 0.05); however, only the global SI-DI was significantly correlated with log10 NT-proBNP (r = -0.469, P = 0.001). In Pearson's correlation analyses, log10 NT-proBNP was significantly correlated with E/e', E/A ratio, early diastolic mitral annular velocity (e'), global peak strain, deceleration time of the E-wave, and LV ejection fraction. In the multiple stepwise regression analysis, the global SI-DI was the strongest independent determinant of log10 NT-proBNP (β = -0.386, P = 0.008).

CONCLUSIONS

The global SI-DI derived from 2DSI correlates well with plasma NT-proBNP levels and may have prognostic value in asymptomatic hypertensive patients with preserved ejection fraction.

[Heart failure with preserved ejection fraction: a systemic disorder?]

When the syndrome of heart failure (HF) is due to left ventricular (LV) systolic dysfunction the clinical manifestations and natural history of the syndrome depend primarily on the severity of LV systolic dysfunction. In contrast, when the syndrome is attributed to LV diastolic dysfunction multiple comorbidities are responsible for the clinical manifestations and the natural history of the syndrome. The present review underscores the multifactorial pathogenesis of the syndrome of HF associated with LV diastolic dysfunction that nowadays is more properly referred to as HF with preserved LV ejection fraction (HFpEF) than to diastolic HF. The prognosis is similarly poor whether HF is due to systolic dysfunction or associated with diastolic dysfunction. The cause of death that is commonly non-cardiovascular in HFpEF supports the pathogenic importance of comorbidities in this condition. Hypertension, chronic kidney disease (CKD), diabetes, obesity and sleep disorder breathing are among the most frequent comorbidities in HFpEF. These comorbidities account for the multiple clinical presentations of the syndrome of HFpEF. Limited functional capacity is in HFpEF largely related to the downward spiral between CKD mediated fluid accumulation and LV stiffness as well as altered ventricular-vascular coupling. The diagnosis of HFpEF currently relies on 2D-Doppler echocardiography findings of impaired LV relaxation and increased LV stiffness and to a lesser extent on biomarkers. Owing to both lack of stringent inclusion and exclusion enrollment criteria and mistaken therapeutic target, placebo-controlled randomized therapeutic trials have been so far negative in HFpEF.

Analysis of circumferential and longitudinal left ventricular systolic function in patients with non-ischemic chronic heart failure and preserved ejection fraction (from the CARRY-IN-HFpEF study)

Heart failure with preserved left ventricular ejection fraction (HFpEF) is implicitly attributed to diastolic dysfunction, often recognized in elderly patients with hypertension, diabetes, and renal dysfunction. In these patients, left ventricular circumferential and longitudinal shortening is often impaired despite normal ejection fraction. The aim of this prospective study was to analyze circumferential and longitudinal shortening and their relations in patients with nonischemic HFpEF. Stress-corrected midwall shortening (sc-MS) and mitral annular peak systolic velocity (S') were measured in 60 patients (mean age 73 ± 13 years) with chronic nonischemic HFpEF in stable New York Heart Association functional class II or III and compared to the values in 120 healthy controls and 120 patients with hypertension without HFpEF. Sc-MS was classified as low if <89% and S' as low if <8.5 cm/s (the 10th-percentile values of healthy controls). Isolated low sc-MS was detected in 46% of patients with HFpEF, 27% of patients with hypertension, and 2% of controls; isolated low S' was detected in 11% of patients with HFpEF, 7% of patients with hypertension, and 5% of controls; and combined low sc-MS and low S' was detected in 26% of patients with HFpEF, 9% of patients with hypertension, and 5% of controls (HFpEF vs others, all p values <0.001). Thus, any alteration of systolic function was found in 83% of patients with HFpEF. The relation between sc-MS and S' was nonlinear (cubic). Changes in S' within normal values corresponded to negligible variations in sc-MS, whereas the progressive decrease below 8.5 cm/s was associated with substantial decrease in sc-MS. In conclusion, circumferential and/or longitudinal systolic dysfunction is present in most patients with HFpEF. Circumferential shortening normalized by wall stress identifies more patients with concealed left ventricular systolic dysfunction than longitudinal shortening.

[State of the art: new developments in cardiac imaging]

Cardiac imaging continues to reveal new anatomical and functional insights into heart disease. In echocardiography, both transesophageal and transthoracic three-dimensional imaging have been fully developed and optimized, and the value of the techniques that have increased our understanding of cardiac mechanics and ventricular function is well established. At the same time, the healthcare industry has released new devices onto the market which, although they are easier to use, have limitations that restrict their use for routine assessment. Tomography's diagnostic and prognostic value in coronary artery disease continues to increase while radiation exposure becomes progressively lower. With cardiac magnetic resonance imaging, myocardial injury and recovery in ischemic heart disease and following acute coronary syndrome can be monitored in exquisite detail. The emergence of new combined tomographic and gamma camera techniques, exclusively developed for nuclear cardiology, have improved the quality of investigations and reduced radiation exposure. The hybrid or fusion images produced by combining different techniques, such as nuclear cardiology techniques and tomography, promise an exciting future.