Can Isovolumic Acceleration Be Used in Clinical Practice to Estimate Ventricular Contractile Function? Reproducibility and Regional Variation of a New Noninvasive Index

Usefulness of tissue Doppler-derived left ventricular isovolumic contraction velocity in patients with heart failure with preserved ejection fraction

BACKGROUND

Heart failure with preserved ejection fraction (HFpEF) is a group of diseases classified by left ventricular (LV) EF, a measure of pump function. However, LVEF does not reflect LV contractility. Previous studies have shown that tissue Doppler-derived LV isovolumic contraction velocity (IVCv) correlates well with the LV peak dP/dt, an index of LV contractility. We explored whether LV IVCv is associated with 1-year post-discharge outcomes in HFpEF.

METHODS

We enrolled 113 patients (median age, 86 years, 45 male) with HFpEF (EF on admission ≥ 50%) who were admitted to our hospital for the treatment of acute HF. Clinical characteristics including echocardiographic data were obtained before discharge. IVCv was obtained from the tissue Doppler waveforms of both the septal and lateral mitral annulus of the apical 4-chamber view and averaged data were used. Primary outcomes were all-cause death or unplanned hospitalization due to HF within the first year.

RESULTS

Among all patients, median LVEF was 61%, left atrial diameter was 47 mm, E/e' was 17.5, and IVCv was 4.5 cm/sec; mean tricuspid regurgitation velocity was 2.6 m/sec. Regarding laboratory data, the median plasma B-type natriuretic peptide level was 185 pg/mL. Thirty-four events occurred (15 deaths, 19 unplanned hospitalizations due to HF) within the first year. In multivariate Cox proportional hazards analyses, IVCv was significantly associated with outcomes (hazard ratio .68, 95% confidence interval .50-.89, p = .0095), independent of general characteristics, echocardiographic measures and pertinent laboratory parameters.

CONCLUSION

LV IVCv was independently associated with 1-year outcomes in patients with HFpEF.

Predictors of early cardiac changes in patients with type 1 diabetes mellitus: An echocardiography-based study

In patients with type 1 diabetes mellitus (T1DM) imaging studies have demonstrated an increased prevalence of left ventricular diastolic dysfunction and increased left ventricular mass (LVM) unrelated to arterial hypertension and ischemic heart disease. The aim of our study was to identify potential predictors of early subclinical changes in cardiac chamber size and function in such patients. Sixty-one middle-aged asymptomatic normotensive patients with T1DM were included in the study. Conventional and tissue Doppler echocardiography was performed and fasting serum levels of glucose, glycated hemoglobin (HbA1c), lipids, and creatinine were measured. We found moderate bivariate correlations of body mass index (BMI) with left atrial volume (r = 0.47, p < 0.01), LVM (r = 0.42, p < 0.01), left ventricular relative wall thickness (r = 0.32, p = 0.01), and all observed parameters of diastolic function of both ventricles. The five-year average value of HbA1c weakly correlated with the Doppler index of left ventricular filling pressure E/e´sept (r = 0.27, p = 0.04). We found no significant association of diabetes duration, five-year trend of HbA1c, serum lipids, and glomerular filtration rate with cardiac structure and function. After adjusting for other parameters, BMI remained significantly associated with left atrial volume, LVM as well as with the transmitral Doppler ratio E/A. In our study, BMI was the only observed parameter significantly associated with subclinical structural and functional cardiac changes in the asymptomatic middle-aged patients with T1DM.

A manifesto for cardiovascular imaging: addressing the human factor

Our use of modern cardiovascular imaging tools has not kept pace with their technological development. Diagnostic errors are common but seldom investigated systematically. Rather than more impressive pictures, our main goal should be more precise tests of function which we select because their appropriate use has therapeutic implications which in turn have a beneficial impact on morbidity or mortality. We should practise analytical thinking, use checklists to avoid diagnostic pitfalls, and apply strategies that will reduce biases and avoid overdiagnosis. We should develop normative databases, so that we can apply diagnostic algorithms that take account of variations with age and risk factors and that allow us to calculate pre-test probability and report the post-test probability of disease. We should report the imprecision of a test, or its confidence limits, so that reference change values can be considered in daily clinical practice. We should develop decision support tools to improve the quality and interpretation of diagnostic imaging, so that we choose the single best test irrespective of modality. New imaging tools should be evaluated rigorously, so that their diagnostic performance is established before they are widely disseminated; this should be a shared responsibility of manufacturers with clinicians, leading to cost-effective implementation. Trials should evaluate diagnostic strategies against independent reference criteria. We should exploit advances in machine learning to analyse digital data sets and identify those features that best predict prognosis or responses to treatment. Addressing these human factors will reap benefit for patients, while technological advances continue unpredictably.

Tissue Doppler imaging is a sensitive echocardiographic technique to detect subclinical systolic and diastolic dysfunction of both ventricles in type 1 diabetes mellitus

Background

Subclinical left (LV) and right ventricular (RV) dysfunction has been demonstrated in type 2 diabetes mellitus and evidence indicates impaired LV diastolic function in type 1 diabetes mellitus (T1DM) as well. The aim of our study was to evaluate the role of tissue Doppler imaging (TDI) in assessment of global LV and RV function in T1DM patients.

Methods

A detailed two-dimensional, pulsed wave Doppler and pulsed wave TDI analysis was performed in 53 normotensive middle-aged T1DM patients and compared to healthy controls.

Results

In T1DM patients TDI analysis revealed reduced mean mitral septal and lateral E’ velocities as well as reduced mean tricuspid E˙t velocity compared to healthy controls (E’sept 8.89 ± 1.89 cm/s vs. 11.50 ± 2.41 cm/s, p < 0.001; E’lat 12.29 ± 2.58 cm/s vs.15.30 ± 2.95 cm/s, p < 0,001; E’t 13.56 ± 2.91 cm/s vs. 15.60 ± 2.99 cm/s, p = 0.001). Mean ratios E/E’sept, E/E’lat and E/E’t were significantly higher in diabetics with cutoff value of 7.4 for E/E’sept and 3.4 for E/E’t, differentiating diabetics with LV and RV diastolic impairement from matched healthy controls (sensitivity 76.5 %, specificity 73.8 % for E/E’sept and sensitivity 72.1 %, specificity 66.7 % for E/E’t). Myocardial acceleration during isovolumetric contraction (IVA) measured at the septal mitral (LV IVA) and lateral tricuspid annulus (RV IVA) was the only parameter indicating reduced contractility of both ventricles in diabetics compared to controls (LV IVA 230.70 ± 61.26 cm/s² vs. 283.32 ± 59.74 cm/s², p < 0,001; RV IVA 275.48 ± 68.08 cm/s² vs. 316.86 ± 80.95 cm/s², p = 0.011). LV IVA had better diagnostic accuracy than RV IVA to predict early contractile impairement in T1DM patients (area under the curve 0.758, p < 0.001 for LV IVA and 0.648, p = 0.017 for RV IVA).

Conclusions

TDI is essential to detect subclinical diastolic deterioration of both ventricles in T1DM patients. TDI-derived IVA might be useful to assess early systolic alterations of both ventricles in T1DM patients.

Non-invasive measuring of the acceleration of contraction of the left ventricle with the Doppler echocardiography

BACKGROUND

Echocardiographically measured ejection fraction (EF) of the left ventricle (LV) is the most useful standard of the LV systolic function. Its limitations are poor delineation of the LV endocardium, pronounced regional disorders of contractility, dyssynchrony of the LV and in particular significant mitral regurgitation. The aim of this research is to evaluate the advantage of Doppler indices of left ventricular function such as index of acceleration of contraction of the LV (AccLV) over EF in patients with heart failure.

METHODS

We performed a prospective observational study. We included 45 patients with known chronic heart failure and 76 healthy subjects. We performed standard echocardiographic measurements. AccLV was calculated by the following formula: AccLV = Vmax LVOT/dt × EDV [cm/s(2) ml]. Vmax LVOT represents the maximum velocity during ejection in the left ventricular outflow tract (LVOT), dt stands for the interval from the beginning of the LV contraction to the achieved Vmax LVOT, EDV represents end-diastolic volume of the LV.

RESULTS

Between patients and healthy subjects we observed statistically significant differences in mean EF values (65.4 ± 6.7 % vs. 38.6 ± 18.0 %; p < 0.001) and of AccLV (12.1 ± 2.88 cm/s(2)ml vs. 4.4 ± 2.1 cm/s(2)ml; p < 0.001). Receiver operating characteristic (ROC) curve showed higher area under the curve values for AccLV in comparison to EF (0.996 vs. 0.897). In the patient group we observed more important correlation between AccLV index and the New York Heart Association (NYHA) functional classes (r = - 0.657; p < 0.001), than between EF and the NYHA classes (r = - 0.539; p < 0.001).

CONCLUSIONS

We could distinguish with higher accuracy between healthy subjects and patients with heart failure LV by calculated AccLV in comparison to EF. AccLV values correlated with NYHA functional classes in patients with heart failure better than EF values.

The effect of indapamide versus hydrochlorothiazide on ventricular and arterial function in patients with hypertension and diabetes: results of a randomized trial

OBJECTIVE

The objective of this study is to compare the effects of 2 types of diuretics, indapamide and hydrochlorothiazide, added to an angiotensin-converting enzyme inhibitor, on ventricular and arterial functions in patients with hypertension and diabetes.

METHODS

This is a prospective, randomized, active-controlled, PROBE design study in 56 patients (57 ± 9 years, 52% men) with mild-to-moderate hypertension and type 2 diabetes, with normal ejection fraction, randomized to either indapamide (1.5 mg Slow Release (SR)/day) or hydrochlorothiazide (25 mg/d), added to quinapril (10-40 mg/d). All patients had conventional, tissue Doppler and speckle tracking echocardiography and assessment of endothelial and arterial functions and biomarkers, at baseline and after 6 months.

RESULTS

Baseline characteristics were similar between groups; systolic and diastolic blood pressures decreased similarly, by 15% and 9% on indapamide and by 17% and 10% on hydrochlorothiazide (P < .05). Mean longitudinal systolic velocity and longitudinal strain increased by 7% and 14% on indapamide (from 5.6 ± 1.8 to 6.0 ± 1.1 cm/s and from 16.2% ± 1.8% to 18.5% ± 1.1%, both P < .05), but did not change on hydrochlorothiazide (P < .05 for intergroup differences), whereas ejection fraction and radial systolic function did not change. Similarly, mean longitudinal early diastolic velocity increased by 31% on indapamide (P < .05), but did not change on hydrochlorothiazide (P < .05 for intergroup differences). These changes were associated with improved endothelial and arterial functions on indapamide, but not on hydrochlorothiazide.

CONCLUSION

Indapamide was found to improve measures of endothelial and arterial functions and to increase longitudinal left ventricular function compared with hydrochlorothiazide in patients with hypertension and diabetes, after 6 months of treatment. This study suggests that indapamide, a thiazide-like diuretic, has important vascular effects that can improve ventriculoarterial coupling.

Ventricular performance after surgery for a congenital heart defect as assessed using advanced echocardiography: from doppler flow to 3D echocardiography and speckle-tracking strain imaging

A varying degree of impairment of ventricular performance is observed over the long-term after surgery for a congenital heart defect (CHD). Impaired ventricular performance has been shown to be of prognostic value for increased risk of cardiovascular events in adult CHD patients. This emphasizes the importance of delineating the timing and cause of this postoperative impairment. Impairment of ventricular performance could develop over time as a consequence of residua, sequelae and complications of the CHD or surgical procedure. Yet, impaired ventricular performance has also been observed immediately after surgery and can persist and/or worsen over time. This postoperative impairment of ventricular performance is the focus of this review. This article provides an overview of echocardiographic techniques currently used to assess ventricular performance. Furthermore, we review current literature describing ventricular performance, as assessed using echocardiography, after correction of a CHD. In general, a decrease in ventricular performance is observed directly after surgery for CHD’s. Subsequent follow-up of ventricular performance is characterized by a varying degree of postoperative recovery. A consistent observation is the persistent impairment of right-ventricular performance after repair in several different subgroups of CHD patients ranging from ventricular septal defect repair to surgery for Tetralogy of Fallot.

Tissue Doppler imaging in coronary artery diseases and heart failure

Recent studies have explored the prognostic role of TDI-derived parameters in major cardiac diseases, such as coronary artery disease (CAD) and heart failure (HF). In these conditions, myocardial mitral annular systolic (S’) and early diastolic (E’) velocities have been shown to predict mortality or cardiovascular events. In heart failure non invasive assessment of LV diastolic pressure by transmitral to mitral annular early diastolic velocity ratio (E/E’) is a strong prognosticator, especially when E/E’ is > or =15. Moreover, other parameters derived by TDI, as cardiac time intervals and Myocardial Performance Index, might play a role in the prognostic stratification in CAD and HF. Recently, a three-dimensional (3-D) TDI imaging modality, triplane TDI, has become available, and this allows calculation of 3-Dvolumes and LV ejection fraction. We present a brief update of TDI.

Right isovolumic contraction velocity predicts survival in pulmonary hypertension

BACKGROUND

Right ventricular function is a strong determinant of prognosis in severe pulmonary hypertension.

METHODS

The aim of this study was to evaluate the prognostic value of estimates of right ventricular function obtained by echocardiography and Doppler tissue imaging and of functional class and 6-min walk distance (6MWD) in 142 patients with either pulmonary arterial hypertension (n = 104) or chronic thromboembolic pulmonary hypertension (n = 38). Echocardiography was prospectively performed, and demographics, medications, associated medical conditions, New York Heart Association class, and 6MWD at inclusion in addition to vital status, transplantation, and hospital admission related to pulmonary hypertension at follow-up were then collected by review of the medical records.

RESULTS

Variables associated with overall survival by univariate analysis were 6MWD (P = .009), functional class (P = .024), tricuspid annular plane systolic excursion (P = .03) and isovolumic peak velocity at the tricuspid annulus (IVCv) (P = .003). On multivariate analysis, IVCv (P = .015) and 6MWD (P = .016) were the only independent predictors of survival. Kaplan-Meier estimates of survival at 1 year were 95% in patients with IVCv > 9 cm/sec and 80% in those with IVCv ≤ 9 cm/sec (P = .002). Intraobserver and interobserver variability of IVCv measurement were 5% and 9%, respectively.

CONCLUSIONS

Measurement of right ventricular function by Doppler tissue imaging, an easy, noninvasive, and reproducible method, is an independent predictor of clinical outcomes in patients with severe pulmonary hypertension.

Effects of atenolol, perindopril and verapamil on haemodynamic and vascular function in Marfan syndrome - a randomised, double-blind, crossover trial

BACKGROUND

Aortic dilatation is the main therapeutic target in patients with Marfan syndrome. Standard treatment with a β-blocker may not lower central pulse pressure - the major objective - because it does not do so in hypertension, unlike angiotensin-converting enzyme inhibitors and calcium-channel blockers. We therefore performed a prospective, randomised, double-blind, crossover trial to compare the effects of these three agents on large artery function and central aortic pressure in patients with Marfan syndrome.

METHODS AND RESULTS

Eighteen patients had applanation tonometry, pulse wave analysis and echocardiography, before and after atenolol 75 mg, perindopril 4 mg and verapamil 240 mg, each given for 4 weeks, in a random order, with 2 weeks between medications. Fourteen patients completed the study. Within-drug comparisons demonstrated that perindopril (-10·3 mmHg, P = 0·002), verapamil (-9·2 mmHg, P = 0·003) and atenolol (-7·1 mmHg, P = 0·01) all reduced central systolic pressure and brachial pressure; central changes were least, and peripheral changes greatest with atenolol but between-drug comparisons (analysis of covariance) were not significant. There was a trend for augmentation to be reduced by perindopril (-6·3%, P = 0·05), verapamil (-5·5%, P = 0·07) and atenolol (-3·2%, P = 0·09). Only atenolol reduced heart rate (by 16%) and delayed expansion in the arch and abdominal aorta (by 8% and 11%) (P < 0·001, P < 0·01 and P < 0·05, respectively, for between-drug comparisons).

CONCLUSIONS

Perindopril, verapamil and atenolol all reduced peripheral and central systolic pressure. As atenolol slowed heart rate and delayed aortic wave travel, β-blockade may have a continuing role in the treatment of patients with Marfan syndrome.

Tissue Doppler-derived measurement of isovolumic myocardial contraction in the pediatric population

Multiple echocardiographic techniques have been utilized to quantify systolic function. The shortening and ejection fraction remain the most commonly used and accepted methods. However, these measures are affected by altered loading conditions, and are not applicable when ventricular geometry differs from the prolate ellipsoid typical of a left ventricle. Mitral valve annular acceleration during isovolumic contraction (IVA) has been proposed as a load independent index of left ventricular contractility. However, published values for IVA demonstrating normal function vary. In addition, the value of IVA which may discern impaired systolic function has not been established. The purpose of this study is to determine a threshold IVA value for abnormal left ventricular function in the pediatric population. Structurally/functionally normal control (n = 90) and dilated cardiomyopathy (study = 64) patients were compared for differences in left ventricular: wall stress (WS), velocity of circumferential fiber shortening (VCFc), ejection fraction (EF), ejection force, and pulsed wave-derived medial and lateral wall IVA. No difference in body surface area (p = 0.61) or gender (p = 0.53) was noted. Left ventricular ejection fraction, ejection force, VCFc, and IVA were significantly lower and WS was significantly higher in the study group (p < 0.01). The medial IVA was 1.71 ± 0.89 m/s(2) for an EF <40%, 1.74 ± 0.70 m/s(2) for an EF = 40-50%, 2.46 ± 0.89 m/s(2) for an EF >50%. The lateral IVA was 1.81 ± 1.03 m/s(2) for an EF <40%, 2.07 ± 0.78 m/s(2) for an EF = 40-50%, 2.54 ± 0.99 m/s(2) for an EF >50%. ROC analysis demonstrated a medial IVA of 1.97 m/s(2) as the cut-off for predicting an EF <50% with a 77% sensitivity of and specificity of 66% (AUC = 0.75, CI = 0.67-0.83, p < 0.01). ROC analysis demonstrated a lateral IVA of 2.31 m/s(2) as the cut-off for predicting an EF <50% with a 73% sensitivity of and specificity of 63% (AUC = 0.72, CI = 0.63-0.82, p < 0.01). IVA lateral of 1.93 m/s(2) or less was associated with heart transplant and death. ICC analysis demonstrated some interobserver variability in IVA measurement (0.57-0.65). The normal IVA of the medial and lateral mitral valve annulus measure over 1.97 m/s(2) and 2.31 m/s(2), respectively; values less than this cut-off are associated with EF <50%. Despite some problems with reproducibility IVA remains a promising method of screening for diminished ventricular contractility in the setting of abnormal geometry.

Cardiac adaptation in acute hypertensive pulmonary edema

The aim of this study was to evaluate the role of left ventricular (LV) dysfunction (global and regional, systolic and diastolic) acute dyssynchrony, ischemic mitral regurgitation (MR), and afterload changes in acute hypertensive pulmonary edema (AHPE). Forty-four consecutive patients were evaluated by comprehensive echocardiography during clinical and radiologic pulmonary edema (63 ± 29 minutes after first dose of treatment) and after 48 to 92 hours. Twenty age- and gender-matched asymptomatic hypertensive and diabetic subjects served as controls. AHPE was associated with increased afterload (estimated arterial elastance 3.0 vs 2.3 mm Hg/ml, p = 0.024) and subsequent decreased longitudinal LV systolic function (mean strain of 6 basal segments -11.0% vs -15.4%; p = 0.015) compared to the stable follow-up state. However, global LV systolic function was maintained (estimated ventricular elastance 1.7 vs 1.6 mm Hg/ml, stroke work 76.7 vs 84.5 cJ, ejection fraction 0.33 vs 0.37, all nonsignificant). Except for diastolic filling time (ratio to cardiac cycle 0.41 vs 0.49, p <0.001), other indexes of diastolic function, dyssynchrony, and MR severity were similar between evaluations. Patients with AHPE had worse ventricular-arterial coupling, systolic function, estimated diastolic stiffness, and filling pressures compared to asymptomatic controls, suggesting a decreased capacity to adapt to changes in loading. In conclusion, acute alterations of systolic and diastolic LV function, myocardial synchrony, and ischemic MR are unlikely mechanisms of AHPE. Rather, AHPE is likely to develop in patients with decreased systolic and diastolic capacity to adapt to acute changes in loading.

Non-geometric echocardiographic indices of ventricular function in patients with a Fontan circulation

BACKGROUND

Complex anatomy and limited windows complicate echocardiographic assessments of ventricular function in Fontan patients. For the Pediatric Heart Network Fontan Cross-Sectional Study, data were acquired from which mean ventricular pressure change during isovolumetric contraction (dP/dt(ic)), Tei index, and maximal systolic annular velocity (S') could be measured. The purpose of this study was to compare these nongeometric indices of ventricular function to cardiac magnetic resonance (CMR) measurements of ventricular ejection fraction (EF).

METHODS

Echocardiographic and CMR studies were performed prospectively using standardized protocols; measurements were completed by core laboratories. Data from both modalities were available from 137 patients.

RESULTS

A weak but statistically significant correlation was observed between mean dP/dt(ic) and CMR-derived EF (r = 0.20, P = .022). This correlation was strengthened when preload was taken into account (r = 0.30, P = .001). Statistically significant correlations did not exist between CMR-derived EF and the Tei index or S'.

CONCLUSIONS

Among Fontan patients, the correlation between CMR-derived EF and nongeometric echocardiographic indices of ventricular function is not strong. Of the indices evaluated, however, mean dP/dt(ic) appears to be the best.

Developments in echocardiographic techniques for the evaluation of ventricular function in children

Echocardiography is a very important tool for the diagnosis and follow-up of children with congenital and acquired heart disease. One of the challenges that remains in paediatric heart disease is the assessment of systolic and diastolic function in children, as this is influenced by growth, morphology and loading conditions. New echocardiographic techniques, such as tissue Doppler, deformation imaging and three-dimensional echocardiography, have great potential application in this field. They may provide new insights into the influence of growth, morphology and loading on cardiac mechanics, and could become useful clinical tools. In this review, we discuss the potential use and limitations of these new echocardiographic techniques in paediatric and congenital heart disease.