Left Ventricular Performance Index Research Articles

Global longitudinal strain is an informative index of left ventricular performance in neonates receiving intensive care

Echocardiographic assessment of left ventricular function is crucial in NICU. The study aimed to compare the accuracy and agreement of global longitudinal strain (GLS) with conventional measurements. Real-life echocardiograms of neonates receiving intensive care were retrospectively reviewed. Shortening fraction (SF), ejection fraction (EF) and S’ measurements were retrieved from health records. GLS was calculated offline from stored images. The association with stroke volume indexed for body weight (iSV) was evaluated by regression analysis. The diagnostic ability to identify uncompensated shock was assessed by ROC curve analysis. Cohen's κ was run to assess agreement. 334 echocardiograms of 155 neonates were evaluated. Mean ± SD gestational age and birth weight were 34.5 ± 4.1 weeks and 2264 ± 914 g, respectively. SF, EF, S’ and GLS were associated with iSV with R2 of 0.133, 0.332, 0.252 and 0.633, (all p < .001). Including all variables in a regression model, iSV prediction showed an adjusted R2 of 0.667, (p < .001). GLS explained 73% of the model variance. GLS showed a better ability to diagnose uncompensated shock (AUC 0.956) compared to EF, S’ and SF (AUC 0.757, 0.737 and 0.606, respectively). GLS showed a moderate agreement with EF (κ = .500, p < .001) and a limited agreement with S’ and SF (κ = .260, p < .001, κ = .242, p < .001). GLS was a more informative index of left ventricular performance, providing the rationale for a more extensive use of GLS at the cotside.

Echo-derived hemodynamic categorization for risk stratification in transthyretin cardiac amyloidosis

Abstract Background Transthyretin cardiac amyloidosis (TTR-CA) is a rare disease characterized by the deposition of abnormal proteins in the heart, which can lead to heart failure (HF) and death. Echocardiography provides valuable diagnostic and prognostic information in CA, but indices of left ventricular performance alone cannot thoroughly characterise patients with restrictive cardiomyopathy. Evaluating the hemodynamic profile by studying the forward flow and left ventricular filling pressure (LVFP) already proved its value in stratifying disease severity in patients with heart failure (HF). Purpose This study evaluated the prognostic relevance of a non-invasive hemodynamic categorization of TTR-CA patients based on the estimation of stroke volume index (SVi) and systolic pulmonary artery pressure (PAPs). Methods Baseline clinical, transthoracic echocardiogram and laboratory data were collected prospectively in patients with diagnosed TTR-CA. Patients were classified into four groups based on forward flow (SVi &amp;lt; or ≥30 ml/m2) and systolic pulmonary artery pressure (PAPs ≥ or &amp;lt;40 mmHg). The four profiles obtained were Profile-A, normal-flow, normal-pressure; Profile-B, low-flow, normal-pressure; Profile-C, normal-flow, high-pressure; Profile-D, low-flow, high-pressure. We assessed the incidence of the composite endpoint of cardiovascular death and HF hospitalization accordingly to the hemodynamic profile. We performed univariate and multivariate Cox regression using profile A as a reference for HR estimation (profile A corresponding to HR=1). Results Fifty-nine patients were enrolled in the analysis (Table). Over a mean follow-up of 35.9 months (IQR 11.7 - 51.2 months) 23 patients met the composite endpoint (10%, 23%, 43%, 60% for Profile A, B, C and D respectively). Compared to Profile A, Profile D showed the greatest risk of CV mortality and HF hospitalization (HR 10.17), followed by Profile C (HR 6.77) and B (HR 3.45), with P-value=0.015. The C-statistic for the model was 0.72. Kaplan-Meier curves confirmed that patients with PAPs &amp;gt;40 mmHg and SVi&amp;lt; 30 ml/m2 presented the highest risk of the composite endpoint (Log-rank P = 0.010) (Figure). Hemodynamic profiling remained an independent predictor of outcome even after adjusting for the NAC stage (Profile B, HR 2.26; Profile C, HR 6.96; Profile D, HR 17.13; P-value=0.0012). Conclusions The proposed echocardiographically-derived hemodynamic classification based on forward-flow and LVFP estimation is useful for TTR-CA patients risk stratification. Patients with low SVi and high PAPs have the greatest risk of CV death and HF hospitalization, even after adjustment for NAC stage. These findings highlight the importance of early detection and monitoring of hemodynamic changes in TTR-CA patients for tailored management and to improve outcomes.Table.Figure.

Cardiac manifestations in patients with classical or cardiac subtype of Fabry disease.

Background:Fabry disease (FD) is an X-linked lysosomal storage disorder engendered by a deficiency of the enzyme α-galactosidase A, leading to systemic accumulation of glycolipids. Studies have reported that the cardiac subtype of FD has a later onset and minimal extracardiac involvement. However, whether the severity of cardiac involvement differs between the classic and cardiac subtypes of FD remains unclear.Methods:We enrolled consecutive patients with classic FD (n = 22; median age [25th–75th percentile], 47.0 [32.75–56.25] years; men, 72.7%) as well as age- and sex-matched patients with a later-onset cardiac subtype of FD who were selected from our cohort of patients with IVS4 919G>A mutation. FD was diagnosed on the basis of clinical symptoms/signs and pedigree screening of index case, plasma α-galactosidase activity, and molecular analysis. Data on clinical manifestations, laboratory findings, and echocardiogram findings were collected before enzyme replacement treatment. Disease severity was evaluated using the Mainz Severity Score Index score.Results:All female patients demonstrated heterozygous mutations, with five, one, and four of them showing normal α-galactosidase activity, classic FD, and cardiac subtype of FD, respectively. The distributions of left ventricular performance indices and comorbidities, including hypertension, diabetes mellitus, and dyslipidemia, were similar between the two groups. Moreover, MSSI cardiovascular scores did not differ significantly between the groups (classic vs cardiac subtype, 10.0 [2.0–12.5] vs 10.5 [9.0–15.25]; p = 0.277).Conclusion:Cardiac manifestations are similar between patients with classic and cardiac subtype of FD.

Area of the pressure-strain loop during ejection as non-invasive index of left ventricular performance: a population study

BackgroundPrevious studies highlighted the usefulness of integrating left ventricular (LV) deformation (strain) and hemodynamic parameters to quantify LV performance. In a population sample, we investigated the anthropometric and clinical determinants of a novel non-invasive index of LV systolic performance derived from simultaneous registration of LV strain and brachial pressure waveforms.MethodsThree hundred fifty-six randomly recruited subjects (44.7% women; mean age, 53.9 years; 47.5% hypertensive) underwent echocardiographic and arterial data acquisition. We constructed pressure-strain loops from simultaneously recorded two-dimensional LV strain curves and brachial pressure waveforms obtained by finger applanation tonometry. We defined the area of this pressure-strain loop during ejection as LV ejection work density (EWD). We reported effect sizes as EWD changes associated with a 1-SD increase in covariables.ResultsIn multivariable-adjusted analyses, higher EWD was associated with age, female sex and presence of hypertension (P ≤ 0.0084). In both men and women, EWD increased independently with augmentation pressure (effect size: + 59.1 Pa), central pulse pressure (+ 65.7 Pa) and pulse wave velocity (+ 44.8 Pa; P ≤ 0.0006). In men, EWD decreased with relative wall thickness (− 29.9 Pa) and increased with LV ejection fraction (+ 23.9 Pa; P ≤ 0.040). In women, EWD increased with left atrial (+ 76.2 Pa) and LV end-diastolic (+ 43.8 Pa) volume indexes and with E/e’ ratio (+ 51.1 Pa; P ≤ 0.026).ConclusionOlder age, female sex and hypertension were associated with higher EWD. Integration of the LV pressure-strain loop during ejection might be a useful tool to non-invasively evaluate sex-specific and interdependent effects of preload and afterload on LV myocardial performance.

Insertion/deletion polymorphism of ACE gene in females with peripartum cardiomyopathy: A case-control study

BackgroundThe role of polymorphism of Angiotensin converting enzyme (ACE) gene and ACE activity in etiopathogenesis, prognosis, and many other clinical parameters in the various form of the cardiovascular disease has been established to some degree of certainty. The pathophysiology of Peripartum cardiomyopathy (PPCM) remains an area of active research. The main aim of our study was to see pattern of ACE- Insertion/Deletion (I/D) allele in PPCM and its implications on left ventricular performance indices. MethodsThis single-center case-control study included 45 cases and 70 controls. The diagnosis of PPCM was established clinically and echocardiographically. ACE genotyping was done by polymerase chain reaction (PCR) method in all subjects. ResultsThe II, ID, and DD genotype was present in 16, 18 and 11 of subjects with PPCM and 48, 19 and 3 of controls respectively. The odds ratio for ACE-II genotype in cases vs. controls was 0.253 (95% CI=0.114–0.558; p=0.007), for that of II genotype was 1.93 (95% CI=0.86–4.3; p=0.107) and for DD genotype was 7.225 (95% CI; 1.88–27.6; p=0.0039). Overall frequency of D allele in cases was significantly higher than controls (odds=4.25; 95% CI=2.01–6.7; p=0.0001). Moreover, ejection fraction, left ventricular volume and linear dimensions were worse in patients with DD genotype. ConclusionACE DD genotype and overall frequency of D allele is significantly higher in patients with PPCM. Also, the presence of DD genotype is associated with worse systolic performance indices measured echocardiographically.

Decrease of the Pericardial Fat around the Heart has a Positive Correlation with Improvement of Left Ventricular Performance

Objective: The objective of the study was to evaluate the effect of an eight week period of very low calorie diet (VLCD) on left ventricular performance and on the amount of pericardial adipose tissue around the heart in obese people without heart disease. This is an extension of the study “Cardiac systolic and diastolic function can be improved over a short period of time in obese patients without heart disease by the very low calorie diet” with the same authors and study group, being currently under evaluation for publication in this Journal. Methods: Fifty-seven obese patients (41 women, 16 men, mean age 48.0±12.0 years, mean BMI 46.1±7.2g/m2) were assigned to a VLCD enriched with vegetables for eight weeks. Transthoracic echocardiography was performed before and after the diet period. Left ventricular size, ejection fraction, myocardial performance index and thickness of pericardial adipose tissue were measured. Results: During the diet period the BMI decreased from 46.1±7.2 kg/m2 to 41.7±6.4 kg/m2 (p<0.0001). The left ventricular performance index decreased from 0.41±0.07 to 0.37±0.07 (p<0.0001) showing significant systolic and diastolic improvement in the performance of left ventricle. The thickness of pericardial fat decreased from 2.2±1.6 mm to 1.4±1.3 mm (p<0.0001). The improvement of the left ventricular myocardial performance index correlated positively with the decrease of pericardial fat (r=0.46, p<0.001). Conclusion: Changing the diet for only eight weeks time caused significant reduction in BMI as well as in the amount of pericardial fat and significant improvement in the systolic and diastolic performance of the left ventricle in obese persons. There was a positive correlation between the improvement on left ventricular performance and the decrease of pericardial fat.

Left ventricular global function index assessed by cardiovascular magnetic resonance for the prediction of cardiovascular events in ST-elevation myocardial infarction.

BackgroundThe left ventricular performance index (LVGFI) as a comprehensive marker of cardiac performance integrates LV structure with global function within one index. In a prospective cohort study of healthy individuals the LVGFI demonstrated a superior prognostic value as compared to LV ejection fraction (LVEF). In patients after ST-segment elevation myocardial infarction (STEMI), however, the role of the LVGFI is unknown. Aim of this study was to investigate the relationship between the LVGFI and infarct characteristics as well as prognosis in a large multicenter STEMI population.MethodsIn total 795 STEMI patients reperfused by primary angioplasty (<12 h after symptom onset) underwent cardiovascular magnetic resonance (CMR) at 8 centers. CMR was completed within one week after infarction using a standardized protocol including LV dimensions, mass and function for calculation of the LVGFI. The primary clinical endpoint of the study was the occurrence of major adverse cardiac events (MACE).ResultsThe median LVGFI was 31.2 % (interquartile range 25.7 to 36.6). Patients with LVGFI < median had significantly larger infarcts, less myocardial salvage, a larger extent of microvascular obstruction, higher incidence of intramyocardial hemorrhage and more pronounced LV dysfunction (p < 0.001 for all). MACE and mortality rates were significantly higher in the LVGFI < median group (p < 0.001 and p = 0.003, respectively). The LVGFI had an incremental prognostic value in addition to LVEF for prediction of all-cause mortality.ConclusionsThe LVGFI strongly correlates with markers of severe myocardial and microvascular damage in patients with STEMI, offering prognostic information beyond traditional cardiac risk factors including the LVEF.Trials registrationClinicalTrials.gov: NCT00712101

Left ventricular function can be continuously monitored with an epicardially attached accelerometer sensor

Preservation of left ventricular (LV) function is crucial for a beneficial outcome in high-risk patients undergoing cardiac surgery. The present study evaluated a motion sensor (accelerometer) for continuous monitoring of LV performance during changes in global and regional LV function. In 11 pigs, an accelerometer was sutured to the epicardium on the anterior apical LV region. Global LV function was modulated by esmolol, epinephrine and fluid loading, whereas regional LV dysfunction was induced by a 3-min occlusion of left anterior descending (LAD) coronary artery. Epicardial acceleration in the circumferential direction was obtained by the accelerometer, and from this signal, epicardial velocity was calculated. Peak systolic velocity was measured and used as an index of LV performance. The accelerometer was compared with left ventricular stroke work (LVSW), ejection fraction and myocardial strain by echocardiography. Accelerometer peak systolic velocity and LVSW changed significantly during all interventions, affecting global LV function. Systolic velocity by the accelerometer increased during epinephrine and fluid loading from 14.1 [10.2; 17.3] to 25.4 [16.7; 28.5] (P < 0.05) and 14.8 [12.5; 18.5] cm/s (P < 0.05), respectively. Esmolol infusion significantly decreased accelerometer peak systolic velocity to 9.4 [7.3; 10.7] cm/s (P < 0.05). Minor changes were seen in the echocardiographic measurements, with significant changes only observed in myocardial strain during the interventions with esmolol and epinephrine. Regional LV dysfunction was clearly detected by the accelerometer during LAD occlusion, and peak systolic velocity was reduced from 14.1 [10.2; 17.3] to 5.7 [5.0; 6.8] cm/s (P < 0.05). The accelerometer demonstrated higher sensitivity and specificity for the detection of myocardial ischaemia than LVSW and ejection fraction. For all interventions, accelerometer peak systolic velocity correlated strongly with LVSW (r = 0.81, P < 0.01) and myocardial strain (r = 0.80; P < 0.01). It was possible to obtain accurate information on LV performance by the use of an epicardially attached accelerometer. The method allows continuous monitoring of LV function and may therefore improve perioperative monitoring of cardiac surgery patients.

The Initial Tangent of the Femoral Arterial Pressure Increase Is an Estimate of Left Ventricular Contractility in Patients Undergoing Cardiacsurgery

Purpose: Assessment of contractile function is a major challenge in patients with left ventricular dysfunction, especially during cardiac surgery. The initial tangent of the femoral arterial pressure increase (tanin) has recently been described to be an estimate of left ventricular (LV) contractility. To confirm these findings tanin was compared to various indices of LV performance in patients undergoing cardiac surgery. Methods: Data from 17 patients were evaluated retrospectively. Myocardial performance was estimated by the echocardiographic indices ejection fraction (EF), shortening fraction (FS), circumferential fiber shortening velocity (Vcf), the parameters of pulse contour analysis area under the curve (AUC) and tanin. Measurements were taken before and after cardiopulmonary bypass (CPB). Results: Tanin increased significantly (813 ± 216 mmHg/s vs. 1490 ± 450 mmHg/s, p in and Vcf correlated strongly (r = 0.70, p in showed only weak correlation with EF (r = 0.36, p = 0.037). There was no significant correlation with FS (r = 0.31, p = 0.079). Tanin and AUC correlated inversely (r = -0.62, p in correlated well with the less preload-dependent parameter Vcf, thus suggesting that tanin may be used as an easily accessible estimate of LV contractility during cardiac surgery.

Correlation of Early Functional Capacity With Biventricular Function and Residual Pulmonary Artery Hypertension Following Mitral Valve Replacement Surgery

To evaluate the functional capacity following mitral valve replacement in the early postoperative period and to determine the correlation of biventricular function and residual pulmonary artery hypertension (PAH) to the functional capacity. On the seventh postoperative day, 53 patients who underwent mitral valve replacement with preoperative diagnosis of PAH underwent a 2-dimensional echocardiographic and Doppler examination for the assessment of right ventricular systolic pressure, along with right ventricular (RV) and left ventricular (LV) myocardial performance indices (MPIs). These assessments were followed by a 6-Minute Walk Test. Five patients were eventually withdrawn from the study. The diminished functional capacity (51.6% ± 4.1% of predicted 6-Minute Walk Test distance for age, gender, weight, and height) significantly correlated with biventricular dysfunction evident from elevated RVMPI (0.35 ± 0.09) and LVMPI (0.52 ± 0.11) (for both Ps ≤ .001). Furthermore, the residual PAH, with mean right ventricular systolic pressure of 37 ± 11 mm Hg, showed negative correlation with the functional capacity (P ≤ .001). In addition, LVMPI had strong association with RVMPI (P ≤ .001). Linear regression analysis demonstrated that LVMPI and right ventricular systolic pressure were independent predictors of functional capacity. The RV and LV function, as quantified by MPI, and the degree of residual PAH are associated with functional capacity impairment after mitral valve replacement, with LVMPI and residual PAH as the independent predictorsqbetween RV and LV performance indices indicate that ventricular interactions contribute to the functional capacity impairment in these patients.

NT-proBNP and cardiac cycle efficiency changes during extubation process in critically ill patients

Several factors can lead to weaning failure from mechanical ventilation (MV). Among these, cardiac dysfunction is one of the main causes. NT-proBNP has been proposed as a biomarker of cardiovascular function during weaning from MV. Unfortunately it does not provide for a continuous monitoring of cardiac function. Pulse wave analysis may serve as a continuous bedside monitoring tool of cardiovascular performance. Cardiac cycle efficiency (CCE) is an indirect index of left ventricular performance obtained by the pulse contour method MostCare (Vygon, Padova, Italy). The aim of this study was to evaluate the correlation between NT-proBNP and CCE and the potential usefulness of such variables during the weaning process from MV.

Predictive Value of Left Ventricular Remodeling by Area Strain Based on Three-Dimensional Wall-Motion Tracking After PCI in Patients with Recent NSTEMI

We aimed to explore whether a novel left ventricular performance index, area strain (AS), based on three-dimensional wall-motion tracking (3-D-WMT) done before and after percutaneous coronary intervention (PCI) could predict left ventricular (LV) remodeling in patients with recent non-ST elevation myocardial infarction (NSTEMI). Sixty-one patients (53.6 ± 8.8 years) with recent NSTEMI were enrolled. Coronary angiography and PCI were undertaken for reperfusion. Parameters of myocardial deformation (including LV end-diastolic volume, LV end-systolic volume, LV ejection fraction, LV global and regional peak area strain) were measured by 3-D-WMT before and 1 week after reperfusion therapy. Six months after reperfusion, LV negative remodeling was defined as lack of improvement in LV function, with increase in LV end-diastolic volume ≥15%. Patients were subdivided into remodeled group (n = 25) and non-remodeled group (n = 36) at follow-up. Patients with negative LV remodeling had significantly higher cardiac troponin I (cTnI) levels at baseline (21.21 ± 12.22 vs. 15.56 ± 8.91 ng/mL; p = 0.0357), higher B-type natriuretic peptide (BNP) level (247.56 ± 177.39 vs. 170.53 ± 97.89 pg/mL; p = 0.0336) and reduced global AS (−27.9 ± 4.6% vs. −31.9 ± 4.3%; p = 0.001) than those without remodeling. Global AS at baseline had a significantly close correlation with cTnI level 36 h after MI (r = 0.71, p < 0.001). Moreover, a weak relationship was found between LV global AS at baseline and BNP level 24 h after myocardial infarction (r = 0.423, p < 0.001). By multivariate logistic regression analysis, lack of improvement of global AS 1 week after PCI was found to be a powerful independent predictor of negative LV remodeling at follow-up (OR = 1.41, 95% CI 1.28–3.27, p = 0.003). In particular, a global AS ≤32% (absolute value) showed a sensitivity and a specificity of 86.1% and 68.0% in predicting negative LV remodeling. These data suggest that AS could be used to assess myocardial global and regional LV function with good feasibility and repeatability. Global AS 1 week after PCI is a good independent predictor of negative LV remodeling after 6-month follow-up.

Peak Power Output to Left Ventricular Mass: An Index to Predict Ventricular Pumping Performance and Morbidity in Advanced Heart Failure

Similar to power-to-weight ratio and weight-to-power ratio, which are measurements of the actual performance of any engine, the ratios of peak power output to left ventricular (LV) mass (peak power/mass) and of peak LV mass to power output (peak mass/power) are indices of LV performance potentially useful in heart failure (HF). This Doppler echocardiographic study was designed to evaluate peak power/mass and peak mass/power in patients with advanced HF compared with healthy subjects and to assess their prognostic value. Power output was measured at rest and at peak exercise in 75 subjects, 60 patients with advanced HF (LV ejection fraction ≤ 35%) and 15 controls. Peak LV power output (W) was calculated as the maximal product of (133 × 10⁻⁶) × stroke volume (mL) × mean arterial pressure (mm Hg) × heart rate (beats/min). LV mass was assessed using a standard M-mode echocardiographic method. Peak power/mass was 1.84 ± 0.46 W/100 g and 0.76 ± 0.31 W/100 g, and peak mass/power was 32 ± 10 g/m²/W and 84 ± 38 g/m²/W in controls and in patients with HF, respectively (both P values < .0001). Peak power/mass was a powerful predictor of outcome on multivariate logistic regression analysis (hazard ratio, 0.907; P = .009). On receiver operating characteristic curve analysis, the areas under the curve for HF-related events were greater for peak power/mass (P = .002) and peak mass/power (P = .011) with respect to resting ejection fraction. Comparisons of Cox models showed that peak power/mass added prognostic value to a model that included age, New York Heart Association class, etiology, ejection fraction, and diastolic dysfunction (P < .0001). Peak power/mass is useful to discriminate and risk stratify patients with advanced HF with additional power with respect to ejection fraction.

Reference Values and Distribution of Conventional Echocardiographic Doppler Measures and Longitudinal Tissue Doppler Velocities in a Population Free From Cardiovascular Disease

This study aimed to investigate the distribution of conventional Doppler measurements, pulsed wave tissue Doppler imaging (pwTDI)- and color tissue Doppler imaging-derived velocities, by age and sex in a healthy population. Longitudinal tissue Doppler velocities were determined in 1266 healthy individuals from standard apical 4- and 2-chamber views. By the pwTDI method, mean ± SD systolic mitral annular velocities were 8.2 ± 1.3 cm/s in women and 8.6 ± 1.4 cm/s in men, and by color tissue Doppler, they were 6.6 ± 1.1 cm/s in women and 6.9 ± 1.3 cm/s in men. With pwTDI, diastolic early mitral annular velocities were 11.8 ± 3.2 cm/s in women and 10.8 ± 3.0 cm/s in men, with corresponding ratios between mitral early flow velocity and early diastolic tissue velocity of 6.7 ± 0.8 in women and 6.4 ± 0.8 in men. By pwTDI, tricuspid annular systolic and early diastolic velocities were 12.5 ± 1.9 and 13.3 ± 3.0, respectively, in women and 12.8 ± 2.2 and 12.5 ± 3.3, respectively, in men. There was a significant decrease in left and right ventricular function with increasing age. Conclusions- The longitudinal mitral and tricuspid annular velocities from this population study are widely applicable as reference values. Reference values for annular velocities should be specified by sex and age. The average of inferoseptal and anterolateral wall velocities may be the preferred index of left ventricular performance.

Allometric scaling of echocardiographic measurements in healthy Spanish foals with different body weight

Scaling in biology is usually allometric, and therefore, the size of the heart may be expressed as a power function of body weight (BW). The present research analyses the echocardiographic measurements in 68 healthy Spanish foals weighed between 70 and 347 kg in order to determine the correct scaling exponent for the allometric equation. The echocardiographic parameters measured were: left ventricular internal dimensions (LVID), free wall thickness (LVFWT), interventricular septum thickness (IVST) at systole (s) and diastole (d), EPSS (distance between the point E of the mitral valve and the interventricular septum), and aorta diameters at the level of the aortic valve (AOD), base of valve leaflets (ABS), sinus of Valsalva (ASV) and sino-tubular junction (AJT). Indices of left ventricular performance were calculated. It was found that LVIDd, IVSTs, AOD, and ASV have a relationship to BW raised to 0.300–0.368 power, whereas left ventricular end-diastolic volume and stroke volume scaled to BW raised to 0.731–0.712 power. With these data, appropriate values can be calculated for normal Spanish foals.

Myocardial performance index during rapidly changing loading conditions

The myocardial performance index is a non-geometric, heart rate-independent echocardiography-derived index of left ventricular performance combining systolic and diastolic function. There is an ongoing debate whether the myocardial performance index is affected by preload or not. Moreover, a systematic evaluation of the effect of changing tidal volume ventilation on the myocardial performance index is still lacking. The aim of our study was to assess whether acute changes in preload and/or different depth of tidal volume ventilation affect the myocardial performance index. In all, 14 anesthetized pigs (35 +/- 2 kg) were studied during changing tidal volumes (VT 5, 10 and 15 mL kg(-1)) at baseline, after removal of 500 cm(3) of blood (haemorrhage) and after retransfusion of shed blood plus additional 500 cm(3) 6% hydroxyethyl starch (fluid loading). Echocardiographic measurements at each experimental stage included myocardial performance index, left ventricular end-diastolic area and fractional area change. Central venous pressure, pulmonary capillary wedge pressure, cardiac output and stroke volume index were obtained by a pulmonary artery catheter. Global end-diastolic volume was obtained by transpulmonary thermodilution. Comparing different loading conditions, we found significant changes in cardiac output, stroke volume index, central venous pressure, pulmonary capillary wedge pressure, global end diastolic volume and left ventricular end-diastolic area, indicating clinically relevant changes in preload. In the haemorrhage group, there was a significant reduction in the myocardial performance index (P < 0.05) independent of tidal volume applied and this was reversed after fluid loading. However, myocardial performance index was significantly impaired (P < 0.05) by high tidal volume ventilation (15 mL kg(-1)), while tidal volumes of 5 and 10 mL kg(-1) had no effect. The myocardial performance index is largely dependent on changes in preload. Moreover, high tidal volume ventilation significantly impaired the myocardial performance index.

Non-invasive assessment of load independent indices of left ventricular performance during cardiac surgery: Validation of a novel approach in an acute porcine model

Aims: Well established biomechanical indices calculated from pressure-volume loops are widely load independent and provide an accurate assessment of systolic and diastolic myocardial function. Routine clinical application has been limited due to the invasiveness and complexity of using combined pressure-volume conductance catheters (CC) in patients.

Papel relativo da remodelação geométrica do ventrículo esquerdo, morfológica e funcional do miocárdio na transição da hipertrofia compensada para a falência cardíaca em ratos com estenose aórtica supravalvar

To evaluate the relative contribution of left ventricular (LV) geometric remodeling and of morphological and functional myocardial changes in rats with induced supravalvar aortic stenosis (SAS), in the transition from compensated hypertrophy to congestive heart failure (CHF). Twenty one weeks after induction of SAS, the rats were classified as controls (CG, n=13), without congestive heart failure (SG, n=11), or with congestive heart failure (SG-HF, n=12). All groups were evaluated with echocardiographic, hemodynamic and morphological study of the myocardium. Twenty one weeks after SAS: mass index (SG-HF>SG>CG, p<0.05); systolic pressure (SG-HF= SG>CG, p<0.05); diastolic pressure (SG-HF>SG>CG, p<0.05); systolic and diastolic meridional stress (SG-HF>SG>CG, p<0.05); LV myocyte cross-sectional area (SG-HF>SG>CG, p<0.05) and hydroxyproline content (SG-HF>SG>CG, p<0.05). In the SG-HF group, LV geometric remodeling was characterized by a significant increase in dimensions and relative thickness of the normal wall (excentric remodeling), whereas the SG group presented a concentric remodeling. Indexes of LV performance in the SG-HF group were significantly lower than those of the SG group. The SG-HF and SG groups differed primarily in the LV geometric remodeling and structural myocardial remodeling process, which established a chronically compensated state in the SG group and triggered CHF in the SG-HF group in the presence of equivalent degrees of impaired contractility.

748 Peak systolic velocity not Tei index appears to be most reliable to differentiate coronary healthy subjects from those with coronary artery disease

Background: Left ventricular (LV) Tei index that is the ratio of isovolumic times and ejection time has been claimed to be a powerful index of LV performance. Tei index (lower the better; 0.9 being the cut-off) however has never been tested using colour tissue Doppler echocardiography, the modality that has excellent temporal resolution at high frame rates. The main purpose of the study was to investigate whether the index could differentiate coronary healthy from coronary artery disease (CAD). Methods: 17 non-consecutive patients with angiographically (CAG) confirmed CAD and 9 subjects without (No-CAD) were recruited from the stress echo archive. CAG was performed after the subjects were diagnosed as having positive velocity-enhanced dobutamine stress echocardiography (DSE). Digital images were post processed at rest and during peak stress on a GE VIVID system equipped with Echopac software. Isovolumic contraction (IVCT) and relaxation times (IVRT), ejection times (ET) along with isovolumic contraction velocity (IVCV) and peak systolic velocities (PSV) were computed from the 4 basal segments of LV. LV ejection fraction (EF) was estimated by modified Simpson’s approach. Tei index was calculated using the formula (IVCT + IVRT)/ET. Data are expressed as mean ± SD. A p value of 0.05). IVCV did not differ. Similar data were obtained during peak stress, average PSV (cm/s) being the most significant differentiating variable between CAD and No-CAD (7.2±1.3 vs 12.3±1.1; p<0.001). Conclusion: Tei index is feasible using colour tissue Doppler echocardiography. However it does not provide additional information on top of the velocity data, confirming that the latter variable is most reliable to differentiate between CAD and No-CAD. The data explains the excellent concordance between velocity quantified DSE and the CAG-diagnosis of CAD. LV FUNCTION – OTHER

Mechanical restitution curves reflect post-ischemic stunning in pigs

ObjectivesThe time constant of mechanical restitution (T(MRC)), proposed to reflect changes in calcium release and uptake, has been shown to increase in left ventriculariz (LV) failure. In this study, we tested the hypothesis that T(MRC) also can identify post-ischemic, reversible LV dysfunction (stunning).DesignStunning was induced by a series of left main coronary artery occlusions in eight anesthetized open chest pigs. Left ventricular pressure–volume relations were assessed using a pressure–volume catheter during right atrial pacing. Mechanical restitution curves (MRCs) were constructed using two different measures of contractile response: maximal first derivative of pressure (CR(dP/dtmax)) and stroke work (CR(SW)).ResultsMean arterial pressure, stroke volume and dP/dtmax were decreased 30 min after stunning. Slopes of end-systolic pressure volume relation and preload recruitable stroke work, however, showed no significant changes after stunning. For MRCs based on CR(dP/dtmax), T(MRC) increased in all eight animals. Using CR(SW), T(MRC) increased in seven out of eight pigs.ConclusionsIschemia–reperfusion induce changes in MRCs based on CR(dP/dtmax) and CR(SW). The MRC concept may have potential as a clinical left ventricular performance index.