Age dependency of the Tei index of myocardial performance

Subclinical central hypothyroidism in patients with hypothalamic-pituitary disease: does it exist?

Central hypothyroidism (CH) is characterized by decreased thyroid hormone production due to insufficient stimulation of an otherwise normal thyroid gland by TSH. In patients with established hypothalamic-pituitary disease, a low FT4 concentration is considered highly specific, although poorly sensitive, for the diagnosis of CH. That would be comparable to diagnosing primary hypothyroidism in patients at risk only when serum FT4 concentrations are below the reference range, missing all patients with subclinical primary hypothyroidism and preventing proper therapy in patients in which thyroxine replacement is clearly beneficial. Cardiac time intervals, especially the isovolumic contraction time (ICT), have been considered the gold standard of peripheral thyroid hormone action. Using Doppler echocardiography, we have previously shown a very high proportion of prolonged ICT in patients with hypothalamic-pituitary disease and serum FT4 levels indistinguishable from controls. As ICT decreased/normalized after thyroxine-induced increases in FT4 concentrations within the normal reference range, prolonged ICT was considered a bona fide diagnostic biomarker of subclinical CH. Those findings challenge the usual interpretation that FT4 concentrations in the mid-reference range exclude hypothyroidism in patients with hypothalamic-pituitary disease. Rather, subclinical central hypothyroidism, a state analogous to subclinical primary hypothyroidism, seems to be frequent in patients with hypothalamic-pituitary disease and normal FT4 levels. They also challenge the notion that thyroid function is usually the least or the last affected in acquired hypopituitarism. The relevance of Doppler echocardiography to correctly diagnose and monitor replacement therapy in both clinical and subclinical forms of CH should improve quality of life and decrease cardiovascular risk, as already demonstrated in patients with clinical and subclinical primary hypothyroidism.

Effect of food intake on echocardiographic measurements in healthy elderly

OBJECTIVE

This study evaluates whether food intake affects systolic and diastolic echocardiographic measurements in healthy seniors.

METHODS

Thirty healthy subjects 65-70 years of age were investigated with echocardiography, at fasting and then 30, 90, and 180 min after a meal.

RESULTS

After 30 min the biggest changes were seen in left ventricular wall stress and myocardial performance index with a decrease of 45% and 33%, respectively, compared to fasting values. Significant (p < .05) increases also were seen in left ventricular stroke volume, left ventricular cardiac output, left ventricular cardiac index, left ventricular outflow velocity-time integral, peak of early diastolic (E) and late diastolic (A) mitral flow velocities, the E/A ratio, pulsed tissue Doppler peak systolic (s') and early (e') and late (a') diastolic velocities, pulmonary vein peak velocities in systole (S) and diastole (D), mitral annular plane systolic excursion (MAPSE), tricuspid annular plane systolic excursion (TAPSE), and global longitudinal strain (GLS) (increases ranging 6%-19%). After 90 min there remained a decrease in wall stress and myocardial performance index of 31% and 17%, respectively, and smaller, but still significant, changes could be seen in left ventricular stroke volume, left ventricular outflow velocity-time integral, MAPSE (lateral), TAPSE, GLS, and a few pulsed tissue Doppler peak systolic velocities and late diastolic velocities. An increase also could be seen in deceleration time of E-wave (DT). After 180 min, all variables except DT were back at baseline or below. No significant changes were seen in S/D ratio, lateral early diastolic velocity (e' lateral) and E/e'ratio.

CONCLUSIONS

This study shows that food intake affects commonly used echocardiographic parameters, both systolic and diastolic, in healthy seniors. With a few exceptions, the changes seen in the older population were less pronounced than previous studies in younger subjects.

Right Ventricular Dysfunction in Early Sepsis and Septic Shock

BACKGROUND

Sepsis is a frequently lethal state, commonly associated with left ventricular (LV) dysfunction. Right ventricular (RV) dysfunction in sepsis is less well understood.

RESEARCH QUESTION

In septic patients, how common is RV dysfunction, and is it associated with worse outcomes?

STUDY DESIGN AND METHODS

We measured echocardiographic parameters on critically ill patients with severe sepsis or septic shock within the first 24 hours of ICU admission. We defined RV dysfunction as fractional area change (FAC) less than 35% or tricuspid annulus systolic plane excursion (TAPSE) less than 1.6 cm. We defined LV systolic dysfunction as ejection fraction (EF) less than 45% or longitudinal strain greater than -19%. Using logistic regression, we assessed the relationship between 28-day mortality and presence of RV dysfunction and LV systolic dysfunction, controlling for receipt of vasopressors, receipt of fluid, mechanical ventilation, and the acute physiology and chronic health evaluation (APACHE II) score.

RESULTS

We studied 393 patients. RV and LV dysfunction were common (48% and 63%, respectively). Mean echocardiographic values were: RV end-diastolic area, 22.4 ± 7.0 cm²; RV end-systolic area, 14.2 ± 6.0 cm²; RV FAC, 38 ± 11%; TAPSE, 1.8 ± .06 cm; RV longitudinal strain, -15.3 ± 6.5%; LV EF, 60% ± 14%; LV longitudinal strain, -16.5% ± 6.0%. Patients with RV dysfunction had higher 28-day mortality (31% vs 16%, P = .001). In our multivariable regression model, RV dysfunction was associated with increased mortality (OR, 3.4; CI, 1.7-6.8; P = .001), and LV systolic dysfunction was not (OR, 0.63; CI, 0.3 -1.2; P = .32) INTERPRETATION: Right ventricular dysfunction is present in nearly half of studied septic patients and is associated with over threefold higher 28-day mortality.

Clinical value of myocardial performance index in patients with isolated diastolic dysfunction

AIMS

The Doppler-derived myocardial performance index (MPI) has been considered as a diagnostic and prognostic Doppler marker for many different clinical conditions. The purpose of this study was to determine the diagnostic accuracy of traditional Pulsed-wave Doppler (PWD-MPI) and Pulsed-wave tissue Doppler imaging (TDI-MPI) and the degree of agreement between these methods in patients with grade-I diastolic dysfunction (DDI) and a normal ejection fraction.

METHODS

Forty-seven consecutive ambulatory patients with DDI were compared to 51 healthy subjects with normal echocardiograms. All subjects underwent measurement of time intervals and MPI with PWD and pulsed TDI.

RESULTS

TDI-MPI and PWD-MPI were significantly higher in patients with DDI than in control subjects: 0.49 ± 0.14 vs. 0.40 ± 0.09 (P < 0.001) and 0.45 ± 0.11 vs. 0.37 ± 0.08 (P < 0.001), respectively. Cutoff values of TDI-MPI > 0.42 and PWD-MPI > 0.40 identified DDI subjects, with sensitivities of 74 and 64%; specificities of 61 and 69%; positive likelihood ratios of 1.9 and 2.0; and negative likelihood ratios of 0.42 and 0.53, respectively; no significant difference was noted between the areas under the ROC curves of TDI-MPI and PWD-MPI (P = 0.77). Bland-Altman plots showed wide limits of agreement between these indices: - 0.17 to 0.23 in healthy subjects and - 0.24 to 0.32 in DDI patients.

CONCLUSION

PWD-MPI and TDI-MPI showed poor clinical agreement and were not reliable parameters for the assessment of left ventricular diastolic function.

Age related structural and functional changes in left ventricular performance in healthy subjects: a 2D echocardiographic study

Left ventricular (LV) adaptation to aging is currently poorly understood. We aimed to characterize age related changes in LV structure and function by studying a large group of healthy subjects across a wide age range. Prospectively enrolled healthy volunteers (n = 778, 327 females; age 18 to 100 years, mean age 49.8 ± 18.1 years), were divided into 4 age groups: 18 to 34 years (n = 165); 35 to 49 years (n = 242), 50 to 79 years (n = 334) and ≥ 80 years (n = 40). All subjects underwent clinical examination, as well as comprehensive transthoracic echocardiogram [TTE]. Body mass index, systolic blood pressure (BP), and left atrial volume (p < 0.0001) increased with age while diastolic BP (p < 0.0001) decreased over time. LV mass/body surface area (BSA) and relative wall thickness increased with age (p < 0.0001) coincident with worsening parameters of diastolic function (E/A and E/Em, p < 0.0001). The ejection fraction and Sm did not change significantly. Stroke volume, ejection time index, flow rate and stroke work significantly increased with age (p < 0.01). The arterial elastance (Ea), a measure of ventricular afterload, and ventricular elastance (Ees), an index of LV systolic stiffness did not change with age nor did their ratio (Ees/Ea) the latter being an expression of ventricular-arterial coupling. Age, gender and LVM were the main independent variables associated with LV systolic function. In conclusion, LV adaptation to aging in a healthy cohort is characterized by concentric LV remodeling, increased contractility and preserved ventricular-arterial coupling.

The Aging Heart

Aging results in progressive deteriorations in the structure and function of the heart and is a dominant risk factor for cardiovascular diseases, the leading cause of death in Western populations. Although the phenotypes of cardiac aging have been well characterized, the molecular mechanisms of cardiac aging are just beginning to be revealed. With the continuously growing elderly population, there is a great need for interventions in cardiac aging. This article will provide an overview of the phenotypic changes of cardiac aging, the molecular mechanisms underlying these changes, and will present some of the recent advances in the development of interventions to delay or reverse cardiac aging.

Improvement of the myocardial performance index in atrial fibrilation patients treated with amiodarone after cardioversion

PURPOSE

This study evaluated the response to electrical cardioversion (EC) and the effect on the myocardial performance index (MPI) in patients with persistent and long-standing persistent atrial fibrillation (AF).

METHODS

We enrolled 103 patients (mean age 69.6 ± 8.9 years, 40.7% males) with a diagnosis of persistent and long-standing persistent AF. EC was applied to all patients after one g of amiodarone administration. Echocardiographic findings before EC were compared in patients with successful versus unsuccessful cardioversions and in patients with maintained sinus rhythm (SR) versus those with AF recurrence at the end of the first month. We also compared echocardiographic data before EC versus at the end of the first month in the same patients with maintained SR.

RESULTS

SR was achieved in 72.8% of patients and was continued at the end of the first month in 69.3% of the patients. The MPI value of all patients was found to be 0.73 ± 0.21. The size of the left atrium was determined to be an independent predictor of the maintenance of SR at 1 month. In subgroup analyses, when we compared echocardiographic findings before EC and at the end of the first month in patients with maintained SR, the MPI (0.66 ± 0.14 vs 0.56 ± 0.09, p < 0.001) values were significantly decreased.

CONCLUSIONS

Our study is the first to show impairment of the MPI, which is an indicator of systolic and diastolic function, in patients with persistent and long-standing persistent AF and improvement of the MPI after successful EC.

Isovolumetric elasticity alteration in the human heart detected by in vivo time-harmonic elastography

Time harmonic elastography (THE) has recently been introduced for measurement of the periodic alteration in myocardial shear modulus based on externally induced low-frequency acoustic vibrations produced by a loudspeaker. In this study, we propose further developments of cardiac THE toward a clinical modality including integration of the vibration source into the patient bed and automated parameter extraction from harmonic shear wave amplitudes, wall motion profiles and synchronized electrocardiographic records. This method has enabled us to evaluate the delay between wall motion and wave amplitude alteration for the measurement of isovolumetric times of elasticity alteration during contraction (τ(C)) and relaxation (τ(R)) in a group of 32 healthy volunteers. On average, the wave amplitudes changed between systole and diastole by a factor of 1.7 ± 0.3, with a τ(C) of 137 ± 61 ms and a τ(R) of 68 ± 73 ms, which agrees with results obtained with the more time-consuming and expensive cardiac magnetic resonance elastography. Furthermore, because of the high sampling rate, elasto-morphometric parameters such as transition times and the area of wave amplitude-cardiac motion cycles can be processed in an automated way for the future clinical detection of myocardial relaxation abnormalities.

Myocardial performance index (MPI) is not influenced by increased left ventricular mass in healthy obese men

BACKGROUND

Notwithstanding its clinical use as a reliable measure of left ventricular performance, little is known about whether myocardial performing index (MPI) is influenced by increased left ventricular mass (LVM) in healthy obese individuals.

AIM

The present study was targeted at investigating the impact of increased LVM on the LV MPI in healthy obese men.

SUBJECTS AND METHOD

Sixty-six normal male subjects were involved in this study. The subjects were divided according to their body mass index (BMI), into group I (BMI=20-24.9, n=37, mean age 33.405±10.277 years) which served as the control group, and group II (BMI=≥ 30, n=29, mean age 39.208±10.214 years). The MPI was determined in all subjects using the following formula proposed by Tei: MPI=IVCT+IVRT/ET. LVM was calculated according to the following Devereux formula as: LVM=0.8[1.04(IVSd+PWTd+LVIDd)-(LVIDd)] +0.6.

RESULTS

There were no significant differences in MPI between control subjects and obese subjects with increased LVM (p>0.05). Additionally, there was no linear correlation between MPI and LVM (R(2)=0.0003, p=0.89).

CONCLUSION

MPI is a simple and accurate tool for the quantitative assessment of left ventricular function. Because of its ease of application, cost effectiveness, and reproducibility, this tool could be regarded as a principal measurement for comprehensive hemodynamic studies. MPI values (according to the Tei index) did not vary significantly between healthy obese and morbidly obese individuals, and therefore may have limited utility for predicting cardiac diseases in at-risk obese individuals.

Diagnosis of subclinical central hypothyroidism in patients with hypothalamic-pituitary disease by Doppler echocardiography

OBJECTIVE

The diagnosis of subclinical central hypothyroidism in hypothalamic-pituitary patients cannot be established by serum markers of thyroid hormone action. Myocardial function by echocardiography has been shown to reflect thyroid hormone action in primary thyroid dysfunction. We evaluated the performance of echocardiography in diagnosing subclinical central hypothyroidism.

DESIGN

Cross-sectional and before and after.

METHODS

Echocardiography and serum thyroid hormones were assessed in overt primary (n=20) and central (n=10) hypothyroidism, subclinical primary hypothyroidism (n=10), hypothalamic-pituitary disease with normal free thyroxine (FT(4); n=25), and controls (n=28). Receiver operating characteristic (ROC) curves were generated using overt hypothyroidism patients and selected cut-off values were applied to detect both primary and central subclinical hypothyroidism. After levothyroxine (l-T(4)) intervention, patients were echocardiographically reevaluated at predefined targets: normal thyrotropin (TSH) in primary hypothyroidism, normal FT(4) in overt central hypothyroidism, and higher than pretreatment FT(4) in echo-defined subclinical central hypothyroidism.

RESULTS

Parameters with highest areas under the ROC curves (area under the curve (AUC) ≥0.94) were as follows: isovolumic contraction time (ICT), ICT/ejection time (ET), and myocardial performance index. Highest diagnostic accuracy (93%) was obtained when at least one parameter was increased (positive and negative predictive values: 93%). Hypothyroidism was echocardiographically diagnosed in eight of ten patients with subclinical primary hypothyroidism and in 14 of 25 patients (56%) with hypothalamic-pituitary disease and normal serum FT(4). Echocardiographic abnormalities improved significantly after l-T(4) and correlated (0.05<P<0.001) with changes in FT(4) (-0.62<r<-0.55) and TSH (0.63<r<0.68) in primary hypothyroidism and with FT(4) in central hypothyroidism (-0.72<r<-0.50).

CONCLUSION

Echocardiography can be useful in diagnosing subclinical central hypothyroidism in patients with hypothalamic-pituitary disease.

Left ventricular function many years after recovery from pre-eclampsia

OBJECTIVE

Epidemiological observations have shown that women with pre-eclampsia are at increased risk for subsequent development of cardiovascular disease. We evaluated maternal haemodynamics in asymptomatic women many years after pre-eclampsia and HELLP (haemolysis, elevated liver enzymes and low platelets) syndrome.

DESIGN

Case-control study.

SETTING

University-based department of obstetrics.

POPULATION

Forty-eight women, 13-18 years after the affected pregnancy: 17 women with a history of HELLP syndrome, 14 women with a history of pre-eclampsia and 17 women following normal pregnancy (control group).

METHODS

Echocardiographic examination was performed in all groups, recording the isovolumetric contraction time and isovolumetric relaxation time (ICT + IVRT), ejection time (ET), myocardial performance index (MPI), transmitral early to atrial filling velocity ratio (MV-E/MV-A), stroke volume (SV) and cardiac output (CO).

MAIN OUTCOME MEASURES

Cardiac function.

RESULTS

Women with previous HELLP syndrome showed a significantly increased MPI (0.34 versus 0.26; P = 0.008) and ICT + IVRT (442.16 versus 415.03; P = 0.01); MV-E/A, SV, ET and CO were not significantly different. Women with a history of pre-eclampsia showed a significantly increased MPI (0.36 versus 0.26; P = 0.006) and decreased ET (317.3 versus 328.93; P = 0.04); ICT + IVRT, MV-E/A, SV and CO were not significantly different.

CONCLUSION

This study confirms epidemiological observations that women with pre-eclampsia are at increased risk for subsequent development of cardiovascular disease. Many years after HELLP syndrome or pre-eclampsia, asymptomatic women have an increased risk for impaired cardiac function as shown by an increased MPI.

Protein kinase A is a target for aging and the aging heart

PKA is an important mediator of signal transduction downstream of G-protein-coupled receptors and plays a key role in the regulation of metabolism and triglyceride storage. It is a ubiquitous cellular kinase that phosphorylates serine and threonine residues in response to cAMP. PKA consists of two regulatory subunits, RI and RII, that are activated by cAMP to release two catalytic subunits, Calpha and Cbeta. We have shown that C57/BL6J male mice lacking the regulatory RIIbeta subunit have extended lifespan and are resistant to age-related conditions including cardiac decline. In addition to being protected from diet-induced pathologies, PKA Cbeta null mutant mice are protected from age-related problems such as weight gain and enlarged livers, as well as cardiac dysfunction and hypertrophy. Several possible mechanisms for the age sparing effects of PKA inhibition are discussed including A kinase anchoring protein signaling, alterations in the beta-adrenergic pathway, and activation of AMPK. Since PKA is a major metabolic regulator of gene signaling, the human gene homologs are potential pharmacological targets for age-related conditions including heart disease associated with declining cardiac performance.

Elasticity-based determination of isovolumetric phases in the human heart

BACKGROUND/MOTIVATION: To directly determine isovolumetric cardiac time intervals by magnetic resonance elastography (MRE) using the magnitude of the complex signal for deducing morphological information combined with the phase of the complex signal for tension-relaxation measurements.

METHODS

Thirty-five healthy volunteers and 11 patients with relaxation abnormalities were subjected to transthoracic wave stimulation using vibrations of approximately 25 Hz. A k-space-segmented, ECG-gated gradient-recalled echo steady-state sequence with a 500-Hz bipolar motion-encoding gradient was used for acquiring a series of 360 complex images of a short-axis view of the heart at a frame rate of less than 5.2 ms. Magnitude images were employed for measuring the cross-sectional area of the left ventricle, while phase images were used for analyzing the amplitudes of the externally induced waves. The delay between the decrease in amplitude and onset of ventricular contraction was determined in all subjects and assigned to the time of isovolumetric tension. Conversely, the delay between the increase in wave amplitude and ventricular dilatation was used for measuring the time of isovolumetric elasticity relaxation.

RESULTS

Wave amplitudes decreased during systole and increased during diastole. The variation in wave amplitude occurred ahead of morphological changes. In healthy volunteers the time of isovolumetric elasticity relaxation was 75 ± 31 ms, which is significantly shorter than the time of isovolumetric tension of 136 ± 36 ms (P < 0.01). In patients with relaxation abnormalities (mild diastolic dysfunction, n = 11) isovolumetric elasticity relaxation was significantly prolonged, with 133 ± 57 ms (P < 0.01), whereas isovolumetric tension time was in the range of healthy controls (161 ± 45 ms; P = 0.053).

CONCLUSION

The complex MRE signal conveys complementary information on cardiac morphology and elasticity, which can be combined for directly measuring isovolumetric tension and elasticity relaxation in the human heart.

Is the aging heart similar to the diabetic heart? Evaluation of LV function of the aging heart with Tissue Doppler Imaging

BACKGROUND AND AIMS

Left ventricular (LV) function in the healthy aging heart is modified by biochemical changes with advancing age. We employed for the first time Tissue Doppler Imaging (TDI), to identify which phase of the cardiac cycle is involved.

METHODS

TDI was performed in 175 aging subjects, free of cardiovascular and/or respiratory disease (group II), and in 182 healthy adults enrolled as the control group (group I), to calculate the Myocardial Performance Index (MPI). The index derives from the values of Isovolumetric Contraction Time (ICT), Isovolumetric Relaxation Time (IRT) and Left Ventricular Ejection Time (LVET) measured in ms, according to the formula: (ICT+IRT)/LVET.

RESULTS

An increase in MPI in group II was shown, with significant lengthening of IRT in comparison with the same value obtained in the control group (group I), ICT and LVET were unchanged.

CONCLUSIONS

The rise in IRT in the aging healthy heart is dependent on diastolic LV dysfunction consequent upon the formation of Advanced Glycosilation End-product (AGE) crosslinks with connectival proteins of interstitial myocardial tissue. Agerelated increase in oxidative stress also modifies some interstitial compounds, favoring hardening of ventricular walls. These changes are similar to those happening in the diabetic heart, and TDI seems to be able to define non-invasively which phase of the cardiac cycle is impaired.

Circulating tissue inhibitor of matrix metalloproteinase-4 (TIMP-4) in systemic sclerosis patients with elevated pulmonary arterial pressure

Decreased levels of matrix metalloproteinases (MMPs) or excess levels of their tissue inhibitors (TIMPs) may contribute to dysregulation of extracellular matrix turnover in systemic sclerosis (SSc). In a cross-sectional study of 106 SSc patients, we measured serum levels of TIMP-4 which is preferentially expressed in cardiovascular structures and searched for correlations with simultaneously performed echocardiography measurements of pulmonary artery systolic pressure (PASP), myocardial performance, and pulmonary function tests. TIMP-4, but not MMP-9, levels were significantly raised in patients with SSc than controls. However, in the subgroup of patients with PASP measurements lower to 40 mmHg (n = 69), TIMP-4 levels were comparable to controls irrespective of the presence of diffuse or limited skin involvement, or lung fibrosis. Individual PASP measurements suggestive of pulmonary hypertension were associated with increased TIMP-4 serum levels (P = .03), independently of age, extent of skin sclerosis, or lung fibrosis, suggesting a cardiopulmonary vasculature-specific role of TIMP-4 activation in SSc.

Comparison of myocardial performance index obtained either by conventional echocardiography or tissue Doppler echocardiography in healthy subjects and patients with heart failure

This study was planned to investigate the normal reference values of myocardial performance index (MPI) obtained by tissue Doppler echocardiography (TDE) and the agreement between MPI measured by TDE and conventional MPI measured by pulsed-wave Doppler (PWD) in healthy subjects and patients with heart failure (HF). Two hundred and three patients with HF and 190 healthy subjects were enrolled in this study. Isovolumic contraction and relaxation time (ICT and IRT) and ejection time (ET) were measured from mitral inflow and left ventricular (LV) outflow. Tissue Doppler echocardiography recordings were obtained at the septal, lateral, inferior, and anterior of the mitral annulus and same time intervals were measured. Myocardial performance index was calculated. The functional capacity of the patients with HF was determined according to New York Heart Association classification. TDE-MPI values were higher than conventional PWD-MPI values in both groups (53%+/-8% vs 48%+/-11%, P<0.0001 in the healthy subjects; 84%+/-21% vs 72%+/-19%, P<0.0001 in the patients with HF). Moderate agreement was found between PWD-MPI and LV mean TDE-MPI in both groups. In identifying patients with moderately or severely decreased LV ejection fraction, TDE-MPI had higher cutoff values than conventional PWD-MPI, and TDE-MPI had higher specificity, sensitivity, negative predictive value, and diagnostic accuracy. In patients with HF, TDE-MPI had a stronger correlation with LV ejection fraction and functional capacity than did PWD-MPI. TDE-MPI is an alternative to conventional PWD-MPI in assessment of cardiac function. However, the higher MPI cutoff points should be considered when this method is used for the evaluation of cardiac function.

Doppler myocardial performance index in assessment of ventricular function in children with single ventricles

BACKGROUND

Quantitative assessment of ventricular function in children with single ventricles is both difficult and subjective because of asymmetric ventricular geometry. The Doppler myocardial performance index (MPI) allows the assessment regardless of ventricular shape. This study was designed to evaluate the feasibility of MPI in assessing ventricular function in children with single ventricles before and after total cavopulmonary connection (TCPC).

METHODS

Subjects consisted of 161 pediatric patients with single ventricles and 80 normal children without heart disease. The maximum positive rate of ventricular pressure change (Max dp/dt) was obtained in 58 patients by cardiac catheterization. Sixty-eight children with single ventricles received TCPC. MPI was calculated from Doppler tracings of ventricular inflow and outflow, then MPI of single ventricles before and after surgery and normal heart were compared.

RESULTS

Normal MPI value was 0.30+/-0.08 in the left ventricle and 0.26+/-0.08 in the right ventricle. Compared to normal children, MPI was significantly higher in 161 children with single ventricles (0.54+/-0.11, P<0.001). MPI correlated inversely with Max (dp/dt) (r=-0.77, P<0.01), and was positively related to age (r=0.54, P<0.01) in patients with single ventricles. MPI did not differ significantly before and after surgery in 68 patients with single ventricles (0.55+/-0.21 vs 0.51+/-0.20, P>0.05). However, MPI in 48 patients of <6 years old decreased significantly (0.55+/-0.21 vs 0.48+/-0.18, P<0.05), suggesting improved ventricular function.

CONCLUSIONS

Compared to normal children, ventricular function is impaired in patients with single ventricles and may worsen with age. MPI provides an accurate method for assessing ventricular function in children with single ventricles before and after TCPC.

Echocardiography in Heart Failure

Echocardiography is well qualified to meet the growing need for noninvasive imaging in the expanding heart failure (HF) population. The recently-released American College of Cardiology/American Heart Association guidelines for the diagnosis and management of HF labeled echocardiography "the single most useful diagnostic test in the evaluation of patients with HF...," because of its ability to accurately and noninvasively provide measures of ventricular function and assess causes of structural heart disease. It can also detect and define the hemodynamic and morphologic changes in HF over time and might be equivalent to invasive measures in guiding therapy. In this article we will discuss: 1) the clinical uses of echocardiography in HF and their prognostic value; 2) the use of echocardiography to guide treatment in HF patients; and 3) promising future techniques for echocardiographic-based imaging in HF. In addition, we will highlight some of the limitations of echocardiography.

Left Ventricular Tei Index in Children: Comparison of Tissue Doppler Imaging, Pulsed Wave Doppler, and M-Mode Echocardiography Normal Values

The Tei index has been found to be useful for analyzing systolic and diastolic global ventricular function in a wide variety of congenital and acquired cardiac abnormalities. However, there are some discrepancies between reports as to the normal values for the Tei index obtained by the different echocardiographic techniques and by different investigators. We conducted a prospective study to determine the normal range of left ventricular Tei index (LVTX) values in a broad sample of children using tissue Doppler imaging, pulsed wave Doppler, and M-mode echocardiography. In all, 289 children with normal echocardiogram findings (age 1 day-18 years, body surface area 0.08-2.4 m(2), heart rate 46-182/min) were studied. The LVTX was calculated by all 3 methods in each patient during a single echocardiographic examination. The normal LVTX values (mean +/- SD) for the 3 techniques were: LVTX-Doppler tissue imaging = 0.38 +/- 0.06; LVTX-pulsed wave Doppler = 0.36 +/- 0.07; and LVTX-M-mode echocardiography = 0.29 +/- 0.08. LVTX-Doppler tissue imaging and LVTX-pulsed wave Doppler values were only slightly but statistically significantly different (P < .05). LVTX-M-mode echocardiography values were consistently and significantly less than those obtained by both of the other two methods (P < .01, respectively). The effects of age, body surface area, and heart rate were not clinically significant. These results are similar but not identical to those from prior studies.

Left ventricle myocardial performance index derived either by conventional method or mitral annulus tissue-Doppler: a comparison study in healthy subjects and subjects with heart failure

OBJECTIVES

The aims of this study were to investigate the clinical agreement between myocardial performance index (MPI) measured conventionally and by pulsed-wave tissue Doppler (PW-TD) of the mitral annulus, and to test whether PW-TD MPI can accurately differentiate between healthy subjects and patients affected by congestive heart failure (CHF) with mild to moderate reduction of systolic function.

BACKGROUND

Calculation of MPI using PW-TD may have advantages over conventional left ventricle inflow/outflow tract pulsed-wave Doppler (PWD) method; for example, all of the data needed for PW-TD MPI calculation can be derived from one single cardiac cycle, whereas with PWD at least two different cycles are needed. Thus, heart rate variability does not interfere with PW-TD MPI.

METHODS AND RESULTS

In group A, we included 70 healthy adults with normal left ventricular ejection fraction and normal diastole, whereas for group B we studied 50 patients with CHF and left ventricular ejection fraction between 35% and 45%. MPI measured with PWD was statistically different (P < .0001) from MPI measured with PW-TD both in group A (0.33 +/- 0.09 vs 0.42 +/- 0.09) and group B (0.69 +/- 0.15 vs 0.79 +/- 0.12). Nonetheless, clinical agreement existed between the two methods in the single subject. Receiver operating characteristic curves showed very high accuracy for both methods to discriminate patients with CHF from healthy subjects; the optimal cutoff point was different and specific to each method: 0.50 for the conventional method and 0.60 for the PW-TD method.

CONCLUSION

We found clinical agreement between MPI measured in the same subject with the conventional PWD method and with PW-TD. Both methods had similarly high diagnostic accuracy for CHF, but this study supports the use of a higher MPI cut-point for best diagnostic accuracy when using the new PW-TD method.

SUMMARY

We performed a study in healthy adults and in patients with congestive heart failure to investigate the clinical agreement between MPI measured conventionally and by PW-TD of the mitral annulus. We found mild agreement between MPI measured by the conventional method and by PW-TD. Both methods had high diagnostic accuracy for CHF. PW-TD method requires a higher MPI cut-point for best diagnostic accuracy.

Left Ventricular Tei Index: Comparison between Flow and Tissue Doppler Analyses

BACKGROUND

It is still unknown whether a correlation exists between left ventricular Tei index obtained by tissue Doppler imaging and that determined by flow Doppler waveforms. This study was conducted to evaluate their relationship and to assess the positional effect on them.

METHODS

Twenty-six healthy subjects and 25 patients with essential hypertension were included. On the tissue Doppler images, the time interval from the end to the onset of the mitral annular velocity pattern during diastole and the duration of the S-wave were used to calculate tissue Doppler Tei index.

RESULTS

The tissue Doppler Tei index correlated with the flow Doppler Tei index at sitting position (r = 0.406, P = 0.003), but not at left lateral decubitus position. The limits of agreement for the Tei index measured by both methods were -0.26 to 0.62 at left lateral decubitus position and -0.09 to 0.55 at sitting position. Preload reduction associated with sitting position with dangling feet raised the Tei index both in the healthy controls [0.54 (0.14) vs 0.42 (0.12), P < 0.001] and in the hypertensives [0.53 (0.15) vs 0.46 (0.12), P = 0.005]. There was a similar positional effect on the tissue Doppler Tei index in the control subjects [0.75 (0.12) vs 0.53 (0.10), P < 0.001].

CONCLUSIONS

Tissue Doppler Tei index does not seem to be a suitable substitute for flow Doppler Tei index. Flow Doppler Tei index is preload dependent and the loading status should be taken into consideration at the application of Tei index to the evaluation of myocardial performance.

Effect of age on left ventricular systolic function in humans: a study of systolic isovolumic acceleration rate

The aim of this study was to examine the effect of age on left ventricular (LV) systolic function in normal healthy adults. Eighty consecutive subjects without cardiovascular disease underwent standard and tissue Doppler (TD) echocardiographic imaging. LV systolic function was assessed by load-dependent indices as ejection fraction (EF) and myocardial systolic velocities by TD as well as by the load-independent index, systolic isovolumic acceleration rate (IVA). None of the echocardiographic measurements of systolic function declined with age (mean IVA for the group, 286 +/- 123 cm s(-2); IVA vs. age, r = 0.21, P = 0.1). Likewise, LV end diastolic dimension, wall thickness, mass and left atrial maximum volume were not significantly related to age. On the other hand, as previously reported, echocardiographic indices of diastolic function showed a significant decline with age (P < 0.05). When the group was stratified by gender, isovolumic velocity and acceleration were higher in men than women, but the differences were not significant (P = 0.12 and 0.37, respectively). No significant relation was observed between age and measurements of LV systolic function by regression analysis in women (P > 0.1). However, in men, a positive correlation was noted between average IVA and age (r = 0.63, P = 0.007). In conclusion, age is not associated with a change in cardiac structure and LV systolic function, but is accompanied by a decline in echocardiographic indices of diastolic function. With respect to gender, age does not appear to influence LV systolic function in women, but is associated with an increase in IVA and septal systolic ejection in men.