A practical approach to the echocardiographic evaluation of diastolic function

Echocardiographic Evaluation of Diastolic Function

Left ventricular diastolic dysfunction is common in patients with heart failure. Echocardiographic evaluation of diastolic function provides the clinician with important information about ventricular relaxation and estimation of filling pressures. Optimal evaluation includes the integration of multiple echocardiographic parameters such as Doppler, M-mode, and volumes. This article aims to review the components of diastolic filling and ventricular performance, as well as discuss the techniques used for the assessment of left ventricular diastolic function.

Early cardiac abnormalities and increased C-reactive protein levels in a cohort of children with sleep disordered breathing

BACKGROUND

This study aims to evaluate left ventricular (LV) structure and function and inflammation in a paediatric population with sleep disordered breathing (SDB) and in control subjects.

METHODS

Forty-nine children with SDB and 21 healthy, age-matched subjects were enrolled. The diagnosis of obstructive sleep apnoea syndrome (OSAS) was confirmed by the laboratory polysomnography, showing an obstructive apnoea/hypopnoea index of more than one per hour, according to the criteria of the American Academy of Sleep Medicine and modified for paediatric population. Fasting blood samples for the biochemical evaluation (including high-sensitivity C-reactive protein (hsCRP) were drawn in the morning, after the polysomnographic examination in all patients with SDB and in the control group. All children underwent a two-dimensional colour Doppler cardiac examination with LV mass assessment and systolic and diastolic function evaluation.

RESULTS

Higher hsCRP levels were observed in subjects with OSAS than in children with primary snoring and in controls (0.8 ± 0.7 vs 0.3 ± 0.1 ng/dl, p = 0.001, and 0.4 ± 0.2 ng/dl, p = 0.01, respectively). The LV diastolic dysfunction was significantly more frequent in patients with severe OSAS and higher hsCRP levels than in control group.

CONCLUSIONS

This study shows that OSAS in children is associated with higher LV mass, early LV diastolic dysfunction and a pro-inflammatory state (high CRP levels). These findings might help to explain the higher incidence of cardiovascular morbidity in patients with OSAS.

The diastolic stress test: a new approach to an old problem

The evaluation of ischemic heart disease is the cornerstone of clinical Cardiology. Although there are many means of ischemic evaluation, all are with their own limitations. While perfusion-based studies are highly sensitive, they lack specificity. Conversely, systolic wall motion analysis with echocardiography tends to have high specificity; however, the sensitivity may be limited by short duration of systolic abnormalities when present. With the advent of Doppler echocardiography, and more specifically tissue Doppler imaging, and strain and strain rate imaging, a more comprehensive evaluation of the left ventricular function is available, including diastole. Diastolic abnormalities in the setting of ischemia are now being studied using these new parameters and have been suggested as a reliable marker of ischemia. Exercise-induced abnormalities in diastolic parameters have improved sensitivities and specificities over traditional stress testing and persist longer than systolic abnormalities. A review of the medical literature regarding the subject will be discussed here.

Elevation of B-type natriuretic peptide is a sensitive marker of left ventricular diastolic dysfunction in patients with maintenance haemodialysis

OBJECTIVE

To determine the clinical value of B-type natriuretic peptide (BNP) in diagnosing left ventricular diastolic dysfunction (LVDD) associated with maintenance haemodialysis (MHD) population.

METHODS

Plasma BNP was determined in 59 MHD patients with normal ejection fraction. The ratio of early to late annular velocity (E'/A') was determined by tissue Doppler imaging as a parameter of diastolic function.

RESULTS

LVDD occurred in 66% of the patients. Receiver-operating characteristic curve analyses identified a cut-off of 353.6 pg ml(-1) as the one with the highest sensitivity and specificity for detecting LVDD.

CONCLUSIONS

Plasma BNP may serve as a potential biomarker in diagnosing LVDD in MHD patients with normal systolic function.

Tissue Doppler of early mitral filling correlates with simulated volume loss in healthy subjects

OBJECTIVES

The accurate noninvasive assessment of preload in emergency department (ED) patients remains elusive. Point-of-care ultrasound (US) imaging, particularly evaluation of the inferior vena cava (IVC), has been shown to be qualitatively helpful. Doppler and tissue Doppler are now routinely available on ED US equipment, but few studies have looked at the correlation of dynamic changes in these parameters in a controlled model of hypovolemia. Our objective was to examine the correlation of Doppler parameters to simulated volume loss in healthy subjects using a lower-body negative pressure (LBNP) model and to compare these measurements to commonly used IVC measurements of preload.

METHODS

Twelve paid volunteers with no known cardiovascular disease between the ages of 23 and 31 years old (mean ± SD = 25.5 ± 2.5 years old) were recruited. Hypovolemia was simulated using graduated LBNP levels with measurements taken at 0, -30, and -60 mm Hg and lower pressures as tolerated. Vital signs were monitored in all patients. US measurements recorded at each negative pressure level included IVC maximum (IVC(max)) and minimum (IVC(min)) dimensions; early (E) and late (A) transmitral filling velocities using pulsed-wave spectral Doppler; and early (E') and late (A') tissue Doppler velocities at the septal ((sep)) and lateral ((lat)) mitral annulus, using pulsed-wave tissue Doppler.

RESULTS

Lower-body negative pressure correlated significantly and positively within subjects for all US parameters except for the A filling wave. E'(lat) and E'(sep) showed the strongest correlation with R² values of 0.749 (95% confidence interval [CI] = 0.577 to 0.854) and 0.738 (95% CI = 0.579 to 0.875) respectively, followed by A'(sep) 0.674 (95% CI = 0.416 to 0.845), IVC(max) 0.638 (95% CI = 0.425 to 0.806), A'(lat) 0.547 (95% CI = 0.280 to 0.802), IVC(min) 0.512 (95% CI = 0.192 to 0.777), and E 0.478 (95% CI = 0.187 to 0.762). Ratios correlated only moderately with LBNP level, including E/ E'(lat) R² of 0.430 (95% CI = 0.131 to 0.706), E/ E'(sep) 0.416 (95% CI = 0.183 to 0.686), and IVC collapsibility index (IVC(CI)) 0.201 (95% CI = 0.003 to 0.681). Vital signs, including heart rate and blood pressure, did not vary significantly with LBNP levels.

CONCLUSIONS

In this pilot study of healthy subjects, tissue Doppler assessment of early diastolic filling correlated most strongly with simulated hypovolemia.

Lack of effects of pioglitazone on cardiac function in patients with type 2 diabetes and evidence of left ventricular diastolic dysfunction: a tissue doppler imaging study

Background

Thiazolidinediones, used for the treatment of patients with type 2 diabetes mellitus (DM2), are associated with an increased incidence of heart failure. We sought to investigate the effects of pioglitazone on novel echocardiographic indices of left ventricular (LV) diastolic function in DM2 patients with LV diastolic dysfunction (LVDD).

Methods

Eighty-eight asymptomatic DM2 patients on metformin and/or sulfonylureas, aged 64.5 ± 7.7 years, without known cardiovascular disease, with normal LV systolic function and evidence of LVDD were randomly assigned to pioglitazone 30 mg/day (n = 42) or an increase in dose of other oral agents (n = 39) for 6 months. All patients underwent transthoracic conventional and Tissue Doppler Imaging echocardiography at baseline and follow-up. The primary end-point was change in early diastolic velocity of the mitral annulus (E').

Results

Improvement of glycaemic control was similar in the 2 groups. A significant difference (p < 0.05) between the 2 groups was found in the treatment-induced changes in fasting insulin, the insulin resistance index HOMA, HDL cholesterol, triglycerides, diastolic blood pressure (all in favor of pioglitazone) and in body weight (increase with pioglitazone). No significant changes were observed in any echocardiographic parameter in either group and did not differ between groups (p = NS for all). E' increased non-significantly and to a similar extent in both groups (p = NS).

Conclusions

In asymptomatic DM2 patients with LVDD, the addition of pioglitazone to oral conventional treatment for 6 months does not induce any adverse or favorable changes in LV diastolic or systolic function despite improvements in glycaemic control, insulin sensitivity, lipid profile, and blood pressure.

Diastolic dysfunction: improved understanding using emerging imaging techniques

Diastolic heart failure is increasing in prevalence. Although the pathophysiology is incompletely understood and current therapeutic strategies are limited, identification of diastolic dysfunction is important. We review the role of contemporary techniques with echocardiography and cardiac magnetic resonance imaging (CMRI) in the assessment of diastolic dysfunction. Cardiac catheterization is the criterion standard for demonstrating impaired relaxation and filling by making direct measurements; however, echocardiography has replaced it as the most clinically used tool. By evaluating mitral inflow pulsed-wave Doppler with and without the Valsalva maneuver, isovolumetric relaxation time, pulmonary venous flow Doppler, color M-mode velocity propagation, tissue Doppler imaging, and speckle tracking, echocardiography is considered an accurate method for diagnosis and grading diastolic dysfunction. Evaluation of diastolic function can also be performed by CMRI. Mitral valve inflow velocities, early deceleration time, and pulmonary vein flow velocities are diastolic parameters that can be measured by phase-contrast CMRI. Cardiac magnetic resonance imaging steady-state gradient echo can evaluate functional dimensions for time-volume curves; and myocardial tagging can assess ventricular diastolic "untwisting," which may be important for improved pathophysiologic understanding. Studies have compared echocardiography and CMRI for diagnosing diastolic dysfunction in small patient groups with similar results. Cardiac magnetic resonance imaging can now provide clinically relevant data regarding the underlying cause of diastolic dysfunction and offers promise to gain mechanistic insights for therapeutic strategy development and clinical trial planning.

Electrocardiographic strain pattern in children with left ventricular hypertrophy: a marker of ventricular dysfunction

The objective of this study was to assess the relation between strain pattern on electrocardiogram (ECG-strain) and echocardiographic indices of left ventricular (LV) structure and function in children with LV hypertrophy (LVH). ECG-strain is a marker of LVH and is associated with adverse cardiovascular prognosis in adults. The significance of ECG-strain and its relation to LV structure and function has not been studied in children. We retrospectively analyzed electrocardiograms (ECGs) and echocardiograms of 101 children enrolled in this study. Subjects were divided into three groups: group I (n = 21) comprised children with LVH confirmed by echocardiography (LVH(echo)) with ECG-strain pattern; group II (n = 54) comprised children with LVH(echo) without ECG-strain pattern; and group III (n = 26) comprised children without LVH (control group). ECG-strain was defined as a down-sloping convex ST-segment depression (> or = 0.1 mV) with an inverted asymmetrical T-wave opposite to the QRS axis in leads V5 and/or V6. LV structure and function was measured using conventional and tissue Doppler echocardiography. ECG-strain was associated with greater interventricular septal thickness, posterior wall thickness, and LV mass index (LVMI) compared with those without ECG-strain (P < 0.0001 for each variable). Concentric LVH was more common in those with ECG-strain (16 of 21 vs. 9 of 54 patients; P = < 0.0001). ECG-strain was associated with systolic, diastolic, and combined systolic-diastolic dysfunction in children with LVH(echo). Among children with LVH, ECG-strain is associated with higher LVMI, concentric pattern of LVH, and LV systolic and diastolic dysfunction. Whether this has similar adverse prognostic implications as it does in adults remains to be determined.

Cardiac aging in mice and humans: the role of mitochondrial oxidative stress

Age is a major risk factor for cardiovascular diseases, not only because it prolongs exposure to several other cardiovascular risks, but also owing to intrinsic cardiac aging, which reduces cardiac functional reserve, predisposes the heart to stress, and contributes to increased cardiovascular mortality in the elderly. Intrinsic cardiac aging in the murine model closely recapitulates age-related cardiac changes in humans, including left ventricular hypertrophy, fibrosis, and diastolic dysfunction. Cardiac aging in mice is accompanied by accumulation of mitochondrial protein oxidation, increased mitochondrial DNA mutations, increased mitochondrial biogenesis, as well as decreased cardiac SERCA2 protein. All of these age-related changes are significantly attenuated in mice overexpressing catalase targeted to mitochondria. These findings demonstrate the critical role of mitochondrial reactive oxygen species in cardiac aging and support the potential application of mitochondrial antioxidants to cardiac aging and age-related cardiovascular diseases.

Preoperative diastolic function predicts the onset of left ventricular dysfunction following aortic valve replacement in high-risk patients with aortic stenosis

INTRODUCTION

Left ventricular (LV) dysfunction frequently occurs after cardiac surgery, requiring inotropic treatment and/or mechanical circulatory support. In this study, we aimed to identify clinical, surgical and echocardiographic factors that are associated with LV dysfunction during weaning from cardiopulmonary bypass (CPB) in high-risk patients undergoing valve replacement for aortic stenosis.

METHODS

Perioperative data were prospectively collected in 108 surgical candidates with an expected operative mortality >or=9%. All anesthetic and surgical techniques were standardized. Reduced LV systolic function was defined by an ejection fraction <40%. Diastolic function of the LV was assessed using standard Doppler-derived parameters, tissue Doppler Imaging (TDI) and transmitral flow propagation velocity (Vp).

RESULTS

Doppler-derived pulmonary flow indices and TDI could not be obtained in 14 patients. In the remaining 94 patients, poor systolic LV was documented in 14% (n = 12) and diastolic dysfunction in 84% of patients (n = 89), all of whom had Vp <50 cm/s. During weaning from CPB, 38 patients (40%) required inotropic and/or mechanical circulatory support. By multivariate regression analysis, we identified three independent predictors of LV systolic dysfunction: age (Odds ratio [OR] = 1.11; 95% confidence interval (CI), 1.01 to 1.22), aortic clamping time (OR = 1.04; 95% CI, 1.00 to 1.08) and Vp (OR = 0.65; 95% CI, 0.52 to 0.81). Among echocardiographic measurements, Vp was found to be superior in terms of prognostic value and reliability. The best cut-off value for Vp to predict LV dysfunction was 40 cm/s (sensitivity of 72% and specificity 94%). Patients who experienced LV dysfunction presented higher in-hospital mortality (18.4% vs. 3.6% in patients without LV dysfunction, P = 0.044) and an increased incidence of serious cardiac events (81.6 vs. 28.6%, P < 0.001).

CONCLUSIONS

This study provides the first evidence that, besides advanced age and prolonged myocardial ischemic time, LV diastolic dysfunction characterized by Vp <or= 40 cm/sec identifies patients who will require cardiovascular support following valve replacement for aortic stenosis.

Gender differences of pulsed and tissue Doppler indexes of left ventricular diastolic function in healthy subjects

BACKGROUND

The purpose of this study is to determine the normative Doppler values and gender differences in left ventricular (LV) diastolic function in healthy subjects at each decade of life.

METHODS

Four hundred sixty-seven male and 455 female healthy subjects, aged 20-90 years, underwent standard echocardiography and tissue Doppler imaging. We divided the subjects into seven groups, based on the decade of their age (i.e., 20s, 30s, 40s, 50s, 60s, 70s, and 80s), and measured standard echocardiographic parameters and Doppler indices.

RESULTS

Females younger than 50 years had significantly higher mitral E velocity, and females older than 40 years had significantly higher mitral A velocity, compared with their male counterparts. There was no difference in mitral E to A velocity ratio (E/A) at any age. The tissue Doppler method showed significantly lower early diastole velocity of the mitral annulus (E a) in females-especially females older than 50 years-than in males (10.7 ± 3.7 versus 11.2 ± 3.7 cm/s, p < 0.025). Mean E/E a ratio was higher in females than in males (6.9 ± 2.4 versus 6.0 ± 2.0, p < 0.0001).

CONCLUSION

Our results indicate gender differences in Doppler indexes of LV diastolic function in healthy subjects. In clinical settings, assessment of LV diastolic function using the Doppler method should take into account patient gender.

Racial differences in atrial fibrillation prevalence and left atrial size

BACKGROUND

Previous studies relying on clinical care data have suggested that atrial fibrillation is less common in African Americans than Caucasians, but the mechanism remains unknown. Clinical care may itself vary by race, potentially affecting the accuracy of atrial fibrillation ascertainment in studies relying on clinical data. We sought to examine racial differences in atrial fibrillation prevalence determined by protocol-driven electrocardiograms (ECGs) obtained in prospective cohort studies and to study racial differences in echocardiographic characteristics.

METHODS

We pooled primary data from 3 cohort studies with atrial fibrillation adjudicated from study protocol ECGs and documentation of potentially important confounders: the Heart and Soul Study (n=1014), the Heart and Estrogen-Progestin Replacement Study (n=2673), and The Osteoporotic Fractures in Men Sleep Study (n=2911). Left atrial anatomic dimensions were compared among races from sinus rhythm echocardiograms in the Heart and Soul Study.

RESULTS

Of the 6611 participants, 268 (4%) had atrial fibrillation: Caucasians had the highest prevalence (5%), and African Americans had the lowest (1%; P<.001 for each compared with all other races). After adjustment for potential confounders, Caucasians had a 3.8-fold greater odds of having atrial fibrillation than African Americans (95% confidence interval, 1.6-8.8, P=.002). Although ventricular and atrial volumes and function were similar in Caucasians and African Americans, Caucasians had a 2 mm larger anterior-posterior left atrial diameter after adjusting for potential confounders (95% confidence interval, 1-3 mm, P<.001).

CONCLUSION

ECG confirmed atrial fibrillation is more common in Caucasians than in African Americans, which might be related to the larger left atrial diameter observed in Caucasians.

Myocardial structure and function by echocardiography in relation to glucometabolic status in elderly subjects from 2 population-based cohorts: a cross-sectional study

BACKGROUND

Left ventricular (LV) diastolic dysfunction has been associated with impaired glucometabolic status. However, studies of older subjects are lacking. We examined associations between echocardiographic indices of LV diastolic function and LV mass index (LVMI) and glucometabolic status among middle-aged and elderly subjects free from heart disease, hypothesizing that the associations would be comparative to younger cohorts.

METHODS

We examined the Age Gene/Environment Susceptibility Reykjavik Study (Iceland; n = 607, 76 +/- 6 years) and the Malmö Preventive Project Re-Examination Study (MPP-RES) cohorts (Sweden; n = 1,519, 67 +/- 6 years), evaluating associations with multivariable regression analysis.

RESULTS

In the Age Gene/Environment Susceptibility Reykjavik Study, LVMI was positively correlated with glycosylated hemoglobin (HbA1c) (P = .001). Otherwise, echocardiographic variables were not associated with glucometabolic status. In the MPP-RES, LVMI increased with increasing glucometabolic disturbance among both older (70-80 years) and middle-aged (57-69 years) subjects. Among older subjects, HbA1c was positively correlated with 2 variables reflecting LV diastolic function: late transmitral peak flow velocity (A) (P = .001) and early transmitral peak flow velocity (E)/early diastolic peak tissue velocity (Em) (P = .046). In middle-aged MPP-RES subjects, increasing glucometabolic disturbance was correlated with increasing late diastolic peak tissue velocity (Am) (P = .002) and, after age adjustment, with increasing A (P = .001) and decreasing Em/Am (P = .009). With age adjustment, Am and A were positively correlated with fasting glucose and HbA1c.

CONCLUSIONS

Contrary to our hypothesis, in 2 independent cohorts of older individuals, associations between glucometabolic status and LV diastolic function were generally weak. These contrast with previous reports, as well as with observations among middle-aged subjects in the present study. Changes in LV diastolic function may be more age-related than associated with glucose metabolism in older subjects.

A case of restrictive cardiomyopathy presenting in fetal life with an isolated pericardial effusion

We describe the evolution during pregnancy of a case of restrictive cardiomyopathy which first presented at 22 weeks' gestation with a large pericardial effusion. Measurements of cardiac function were normal and remained near normal until late in the third trimester, when pulsed and tissue Doppler data suggested impairment in ventricular relaxation. This disease progressed in postnatal life to symptomatic restrictive cardiomyopathy by 2 years of age necessitating cardiac transplant. To our knowledge, this is the first time this unusual association has been reported.

PQ interval in patients with Fabry disease

Fabry disease (FD) is an X-chromosomal inherited lysosomal storage disease resulting in intracellular storage of globotriaosylceramide. Cardiac involvement is most frequently manifested as left ventricular hypertrophy. However, patients with FD may also have from various conduction abnormalities particularly affecting atrioventricular (AV) conduction. The present study was designed to analyze primarily AV conduction abnormalities on baseline electrocardiograms of patients with FD and to investigate the correlation with echocardiographic findings. Electrocardiograms at rest of 207 patients with FD were compared to echocardiograms. PQ-interval shortening and first-degree AV block could be found in only 29 cases (14%) and 3 cases (1.4%), respectively. No echocardiographic differences could be found in patients with and without PQ-interval shortening, including left ventricular hypertrophy, atrial size, and diastolic parameters. Furthermore, no correlation of the PQ interval with any echocardiographic parameters was detected. There was no difference between men and women in baseline clinical and electrocardiographic parameters. In conclusion, shortening of the PQ interval was not a common electrocardiographic finding in patients newly diagnosed with FD. Furthermore, no correlation with typical echocardiographic findings or disease stage in FD at baseline could be found.

Echocardiographic findings and NT-proBNP level in type-2 diabetic patients with and without ischemic heart disease

The aim of this study was to determine whether there are differences in echocardiographic findings or in the level of a biochemical marker (i.e. N-terminal probrain natriuretic peptide [NT-proBNP]) between controls and type-2 diabetic patients with or without ischemic heart disease. Echocardiography was used to assess left ventricular function and morphology. In addition, the plasma NT-proBNP concentration was measured. The prevalence of diastolic dysfunction was greater in diabetics without ischemic heart disease than in controls (88% vs. 74%, respectively; P< .001) and the NT-proBNP concentration was higher (350.6+/-197.8 vs. 281.7+/-190.4 fmol/mL; P< .001). Diabetics with ischemic heart disease had a higher NT-proBNP concentration than those without (720.4+/-278.1 vs. 350.6+/-197.8 fmol/mL, respectively; P< .001). An NT-proBNP concentration >490 fmol/mL had a sensitivity of 84% and a specificity of 75% for detecting ischemic heart disease in diabetics.

A, Ribeiro JM. Is there a link between glucose levels and heart failure? An update

It has been well documented that there is an increased prevalence of standard cardiovascular (CV) risk factors in association with diabetes and with diabetes-related abnormalities. Hyperglycemia, in particular, also plays an important role. Heart failure (HF) has become a frequent manifestation of cardiovascular disease (CVD) among individuals with diabetes mellitus. Epidemiological studies suggest that the effect of hyperglycemia on HF risk is independent of other known risk factors. Analysis of datasets from populations including individuals with dysglycemia suggests the pathogenic role of hyperglycemia on left ventricular function and on the natural history of HF. Despite substantial epidemiological evidence of the relationship between diabetes and HF, data from available interventional trials assessing the effect of a glucose-lowering strategy on CV outcomes are limited. To provide some insight into these issues, we describe in this review the recent important data to understand the natural course of CV disease in diabetic individuals and the role of hyperglycemia at different times in the progression of HF.

Serum levels of NT-proBNP as surrogate for cardiac amyloid burden: new evidence from gadolinium-enhanced cardiac magnetic resonance imaging in patients with amyloidosis

BACKGROUND

The prognostic value of NT-proBNP has been recognized in patients with amyloidosis complicated by cardiac involvement. We aimed to use contrast enhanced cardiac magnetic resonance imaging (CMR) to identify functional and structural alterations related to levels of NT-proBNP better to understand the mechanisms of its release in cardiac amyloidosis.

METHODS AND RESULTS

CMR was performed on a 1.5-T scanner in 34 patients with biopsy proven amyloid light chain (AL; n = 27) or hereditary transthyretin related (TTR; n = 7) amyloidosis. NT-proBNP was higher in patients with (n = 25) compared to patients without cardiac involvement (n = 9) (2931 (IQR: 972-8629; min-max: 25-27,277) pg/ml vs. 177 (IQR: 71-1431; min-max: 22-7935) pg/ml, p = 0.008). ROC analysis identified a NT-proBNP of <2426.5 pg/ml as optimal discriminator for event free survival (682 +/- 65 days). NT-proBNP did not correlate with LV- ejection fraction, end-diastolic and end-systolic volumes or stroke volume. There was a moderate correlation between NT-proBNP and LV-mass (R = 0.52, p = 0.003) and extent of late gadolinium enhancement (LGE; R = 0.41, p = 0.04).

CONCLUSIONS

This study confirms the prognostic value of NT-proBNP in patients with AL and TTR amyloidosis and provides the novel finding that NT-proBNP correlates with surrogates of myocardial amyloid burden such as LV-mass and LGE, supporting the concept of NT-proBNP as a biomarker reflecting the severity of cardiac amyloid infiltration.

Noninvasive imaging of the heart and coronary arteries

There are multiple imaging modalities currently available to noninvasively evaluate the heart and coronary arteries. Choosing the most appropriate modality depends on the pertinent clinical question and the underlying patient characteristics. This article provides an overview of the fields of echocardiography, myocardial perfusion imaging, cardiac computed tomography, and cardiac magnetic resonance imaging, with particular attention to specific clinical applications for cardiac surgery patients.

Myocardial performance index derived from brachial-ankle pulse wave velocity: a novel and feasible parameter in evaluation of cardiac performance

BACKGROUND

Right brachial pre-ejection period (rbPEP), brachial-ankle pulse wave velocity (baPWV), and right brachial ejection time (rbET) can be automatically determined from an ABI-form device. The aims of this study are to test the applicability of baPWV-derived myocardial performance index (MPI) (defined as the ratio of rbPEP divided by its own s.d. + baPWV divided by its own s.d. to rbET divided by its own s.d.) as an indicator of combined left ventricular (LV) systolic and diastolic functions.

METHODS

A sum of 215 patients were consecutively included. The rbPEP, baPWV, and rbET were measured using an ABI-form device and LV function was determined by echocardiography.

RESULTS

After a multivariate analysis, diastolic blood pressure (beta = 0.220, P < 0.001), LV ejection fraction (LVEF) (beta = -0.291, P < 0.001), transmitral E wave velocity (E) (beta = -0.106, P = 0.032), early diastolic mitral annular velocity (Ea) (beta = -0.142, P = 0.009), and ET obtained by tissue Doppler echocardiography (beta = -0.397, P < 0.001) were the major determinants of baPWV-derived MPI. The area under the curve for rbPEP, baPWV, rbET, rbPEP/rbET, and baPWV-derived MPI in prediction of Ea <8 cm/s, E/Ea >10, or LVEF <50% were 0.69, 0.76, 0.67, 0.73, and 0.83, respectively.

CONCLUSIONS

BaPWV-derived MPI had a significant correlation with echocardiographic LV diastolic and systolic function. It may be a novel and feasible indicator in assessment of global LV function.

Diagnostic approaches for diabetic cardiomyopathy and myocardial fibrosis

In diabetes mellitus, alterations in cardiac structure/function in the absence of ischemic heart disease, hypertension or other cardiac pathologies are termed diabetic cardiomyopathy. In the United States, the prevalence of diabetes mellitus continues to rise and the disease currently affects about 8% of the general population. Hence, the use of appropriate diagnostic strategies for diabetic cardiomyopathy, which may help correctly identify the disease at early stages and implement suitable corrective therapies is imperative. Currently, there is no single diagnostic method for the identification of diabetic cardiomyopathy. Diabetic cardiomyopathy is known to induce changes in cardiac structure such as, myocardial hypertrophy, fibrosis and fat droplet deposition. Early changes in cardiac function are typically manifested as abnormal diastolic function that with time leads to loss of contractile function. Echocardiography based methods currently stand as the preferred diagnostic approach for diabetic cardiomyopathy, due to its wide availability and economical use. In addition to conventional techniques, magnetic resonance imaging and spectroscopy along with contrast agents are now leading new approaches in the diagnosis of myocardial fibrosis, and cardiac and hepatic metabolic changes. These strategies can be complemented with serum biomarkers so they can offer a clear picture as to diabetes-induced changes in cardiac structure/function even at very early stages of the disease. This review article intends to provide a summary of experimental and routine tools currently available to diagnose diabetic cardiomyopathy induced changes in cardiac structure/function. These tools can be reliably used in either experimental models of diabetes or for clinical applications.

Diagnostic accuracy of plasma brain natriuretic peptide and aminoterminal‐proBNP in mild heart failure depends on assay and introduction of therapy

OBJECTIVE

A reliable biochemical marker of left ventricular dysfunction (LVD) could improve diagnostic accuracy. The aim of this study was to compare the correlation of measurements of brain natriuretic peptide (BNP) and N-terminal proBNP (NT-proBNP) with different assays. The diagnostic accuracy of the tests in mild heart failure (HF) was estimated before and after the start of therapy.

MATERIAL AND METHODS

Doppler echocardiography and measurements of plasma BNP and NT-proBNP were performed in 150 patients.

RESULTS

Systolic dysfunction (LV ejection fraction 0.45) was present in 22 patients, and 58 had only abnormalities in LV filling. P-NT-proBNP based on two different assays demonstrated a moderate correlation (r = 0.57, p<0.0001) and a concentration-dependent systematic difference. Excellent correlation (r = 0.95, p<0.0001) was found between BNP and NT-proBNP based on two-site antibody assays, but was moderate between BNP and a one-site antibody NT-proBNP assay (r = 0.58, p<0.0001). Areas under the receiver operating characteristic (ROC) curves (AUCs) were 0.93 (95 % CI, 0.90-0.98) for BNP, 0.95 (0.91-0.99) for NT-proBNP (two-site antibody assay) and 0.77 (0.70-0.85) for the one-site antibody NT-proBNP assay (p = 0.0001). At re-evaluation of LVD at 6 and 12 months, AUCs of BNP were 0.81 (0.74-0.99) and 0.83 (0.76-0.89), respectively, and AUCs of NT-proBNP (two-site) were 0.84 (0.77-0.91) and 0.87 (0.81-0.93), respectively. Using the baseline threshold reduced the sensitivity and specificity of BNP and NT-proBNP measurements.

CONCLUSIONS

BNP and NT-proBNP measurements demonstrated assay-dependent correlations. Measurement of p-BNP or p-NT-proBNP by a two-site antibody assay demonstrated potential as an indicator of mild, incident HF, but the applicability of the index tests was limited over time and was likely influenced by therapeutic interventions.

Diastolic abnormalities as the first feature of hypertrophic cardiomyopathy in Dutch myosin-binding protein C founder mutations

OBJECTIVES

To test the hypothesis that carriers of Dutch founder mutations in cardiac myosin-binding protein C (MYBPC3), without left ventricular hypertrophy (LVH) or electrocardiographic abnormalities, have diastolic dysfunction on tissue Doppler imaging (TDI), which can be used for the screening of family members in the hypertrophic cardiomyopathy (HCM) population.

BACKGROUND

TDI is a more sensitive technique for the assessment of left ventricular contraction and relaxation abnormalities than is conventional echocardiography.

METHODS

Echocardiographic studies including TDI were performed in genotyped hypertrophic cardiomyopathy patients (genotype-positive, G+/LVH+; n = 27), mutation carriers without LVH (G+/LVH-; n = 27), and healthy controls (n = 55). The identified mutations in MYBPC3 in the G+/LVH+ subjects were c.2864_2865delCT (12 subjects), c.2373dupG (n = 8), and p. Arg943X (n = 7). In the G+/LVH- subjects, the following mutations were identified: c.2864_2865delCT (n = 11), c.2373dupG (n = 8), and p. Arg943X (n = 8).

RESULTS

Mean TDI-derived systolic and early and late diastolic mitral annular velocities were significantly lower in the G+/LVH+ subjects compared with the other groups. However, there was no difference between controls and G+/LVH- subjects. Mean TDI-derived late mitral annular diastolic velocities were significantly higher in the G+/LVH- subjects compared with controls and G+/LVH+ subjects. Using a cut-off value of mean +/- 2 SD, an abnormal late mitral annular diastolic velocity was found in 14 (51%) of G+/LVH- patients. There was no difference among the 3 different mutations.

CONCLUSIONS

In contrast to earlier reports, mean mitral annular systolic velocity and early mitral annular diastolic velocity velocities were not reduced in G+/LVH- subjects, and TDI velocities were not sufficiently sensitive for determination of the affected status of an individual subject. Our findings, however, support the theory that diastolic dysfunction is a primary component of pre-clinical HCM.

Assessment of left ventricular diastolic function using color kinesis: differentiation between normal and pseudonormalized patterns

PURPOSE

Doppler examination of transmitral flow has been widely used to noninvasively assess left ventricular (LV) diastolic function. However, it has been demonstrated that transmitral flow velocity is dependent on LV relaxation and left atrial pressure. Increases in left atrial pressure compensate for the effects of impaired LV relaxation, frequently resulting in a "pseudonormalization" of the transmitral flow pattern. The purpose of this study was to assess whether analysis of diastolic color kinesis (CK) can be applied to differentiation between normal and pseudonormalized (PN) patterns of LV inflow.

METHODS

We studied 60 subjects with a ratio of early to late transmitral peak velocities (E/A) greater than 1.0 according to conventional Doppler echocardiography. All subjects simultaneously underwent measurement of the early diastolic mitral annular velocity (e'), which was measured by tissue Doppler imaging, and LV ejection fraction (EF), which was calculated by the modified Simpson method. Study subjects were classified into the following three groups according to the value of e' and EF: (1) the normal group (e' > 10 cm/s, EF > 60%), including 20 subjects (mean age 35 ± 10 years); (2) the PN1 group (e' < 7 cm/s, EF > 50%), consisting of 20 patients [mean age 63 ± 11 years, 15 patients with hypertensive heart disease (HHD), 5 patients with aortic valve stenosis]; and (3) the PN2 group (e' < 7 cm/s, EF < 50%), consisting of 20 patients (mean age 61 ± 17 years, 18 patients with dilated cardiomyopathy, 2 patients with HHD). Diastolic CK images were obtained for each subject from the LV midpapillary short-axis view. Analysis of CK diastolic images was performed using ICK software. The CK-diastolic index (CK-DI) was defined as the calculated LV segmental filling fraction during the first 30% of diastole, expressed as a percentage. The mean CK-DI was determined from the average CK-DI of six LV segments.

RESULTS

The mean CK-DI was 70.9% ± 6.5% in the normal group, 46.3% ± 10.4% in the PN1 group, and 36.3% ± 5.1% in the PN2 group. The mean CK-DI was significantly reduced in the PN1 and PN2 groups compared with the normal group (P < 0.0001). Although there was no difference in e' (PN1 group: 4.6 ± 1.8 cm/s, PN2 group: 4.4 ± 1.7 cm/s) between the two pseudonormalized patient groups, the mean CK-DI was significantly reduced in the PN2 group compared with the PN1 group (P < 0.005). The reduction in mean CK-DI was seen not only in pseudonormalized patients with LV systolic dysfunction but also in those with preserved LV systolic function.

CONCLUSION

The analysis of diastolic CK with ICK software is a useful method for detecting delayed early diastolic relaxation. We concluded that diastolic CK images may be applied to differentiating between normal and pseudonormalized patterns of LV inflow.

Overexpression of catalase targeted to mitochondria attenuates murine cardiac aging

BACKGROUND

Age is a major risk for cardiovascular diseases. Although mitochondrial reactive oxygen species have been proposed as one of the causes of aging, their role in cardiac aging remains unclear. We have previously shown that overexpression of catalase targeted to mitochondria (mCAT) prolongs murine median lifespan by 17% to 21%.

METHODS AND RESULTS

We used echocardiography to study cardiac function in aging cohorts of wild-type and mCAT mice. Changes found in wild-type mice recapitulate human aging: age-dependent increases in left ventricular mass index and left atrial dimension, worsening of the myocardial performance index, and a decline in diastolic function. Cardiac aging in mice is accompanied by accumulation of mitochondrial protein oxidation, increased mitochondrial DNA mutations and deletions and mitochondrial biogenesis, increased ventricular fibrosis, enlarged myocardial fiber size, decreased cardiac SERCA2 protein, and activation of the calcineurin-nuclear factor of activated T-cell pathway. All of these age-related changes were significantly attenuated in mCAT mice. Analysis of survival of 130 mice demonstrated that echocardiographic cardiac aging risk scores were significant predictors of mortality. The estimated attributable risk to mortality for these 2 parameters was 55%.

CONCLUSIONS

This study shows that cardiac aging in the mouse closely recapitulates human aging and demonstrates the critical role of mitochondrial reactive oxygen species in cardiac aging and the impact of cardiac aging on survival. These findings also support the potential application of mitochondrial antioxidants in reactive oxygen species-related cardiovascular diseases.

Cardiac dysfunction assessed by echocardiographic tissue Doppler imaging is an independent predictor of mortality in the general population

BACKGROUND

Tissue Doppler imaging (TDI) detects left ventricular dysfunction in patients with heart failure and normal ejection fraction, but the prognostic significance of left ventricular dysfunction by TDI in the general population is unknown.

METHODS AND RESULTS

Within the Copenhagen City Heart Study, a large community-based population study, cardiac function was evaluated in 1036 participants by both conventional echocardiography and TDI. Averages of peak systolic (s'), early diastolic (e'), and late diastolic (a') velocities from 6 mitral annular sites were used. TDI was furthermore quantified by a combined index (eas index) of diastolic and systolic performance: e'/(a' x s'). During follow-up (median, 5.3 years), 90 participants died. Left ventricular dysfunction by TDI, in terms of low s' (hazard ratio, 1.23 per 1-cm/s decrease; P<0.05) and a' (hazard ratio, 1.20 per 1-cm/s decrease; P=0.001), were significant predictors of death in Cox proportional-hazards models adjusted for clinical variables (age, sex, body mass index, heart rate, hypertension, diabetes mellitus, and ischemic heart disease) and conventional echocardiography. The adjusted hazard ratio for death in the third tertile compared with the first tertile of the combined index of systolic and diastolic performance by TDI was 2.5 (P<0.005).

CONCLUSIONS

In the general population, in which most are free of left ventricular systolic dysfunction and restrictive diastolic filling using conventional echocardiographic parameters, left ventricular dysfunction by TDI is a powerful and independent predictor of death, especially when systolic performance and diastolic performance are considered together, recognizing their interdependency and their complex relation to deteriorating cardiac function.