Comparative analysis of left ventricle function and deformation imaging in short and long axis plane in cardiac magnetic resonance imaging

Background

Advancements in cardiac imaging have revolutionized our understanding of ventricular contraction. While ejection fraction (EF) is still the gold standard parameter to assess left ventricle (LV) function, strain imaging (SI) has provided valuable insights into ventricular mechanics. The lack of an integrative method including SI parameters in a single, validated formula may limit its use. Our aim was to compare different methods for evaluating global circumferential strain (GCS) and their relationship with global longitudinal strain (GLS) and EF in CMR and how the different evaluations fit in the theoretical relationship between EF and global strain.

Methods

Retrospective monocenter study. Inclusion of every patient who underwent a CMR during a 15 months period with various clinical indication (congenital heart defect, myocarditis, cardiomyopathy). A minimum of three LV long-axis planes and a stack of short-axis slices covering the LV using classical steady-state free precession cine sequences. A single assessment of GLS on long axis (LAX) slices and a double assessment of GCS and EF with both short axis (SAX) and LAX slices were made by a single experienced CMR investigator.

Results

GCS-SAX and GCS-LAX were correlated (r = 0.77, P < 0.001) without being interchangeable with a high reproducibility for GCS, GLS and EF. EF calculated from LAX images showed an overestimation compared to EF derived from SAX images of 7%. The correlation between calculated EF and theoretical EF derived from SI was high (r = 0.88 with EF-SAX, 0.95 with EF-LAX).

Data conclusion

This study highlights the need to integrate strain imaging techniques into clinical by incorporating strain parameters into EF calculations, because it gives a deeper understanding of cardiac mechanics.

Left ventricular remodeling in twin pregnancy, noninvasively assessed using hemodynamic forces and pressure-volume relation analysis: prospective, cohort study

This study was designed to prospectively investigate the pattern of intraventricular hemodynamic forces (HDFs) associated with left ventricular (LV) function and remodeling in women with uncomplicated twin pregnancy. Transthoracic echocardiography was performed on 35 women (aged 35.9 ± 4.7-yr old) during gestation (T1, <14 wk; T2, 14-27 wk; T3, >28 wk) and 6-7 mo after delivery (T0). LV HDFs were computed from echocardiography long-axis data sets using a novel technique based on endocardial boundary tracking, both in apex-base (A-B) and latero-septal (L-S) directions. HDF distribution was evaluated by L-S over A-B HDF ratio (L-S:A-B HDF ratio). At T1, L-S:A-B HDF ratio was higher than in T0 (P < 0.05) indicating HDF misalignment. At T2, a slight impairment of cardiac function was then recorded with a reduction of global longitudinal strain (GLS) and left ventricular end-systolic elastance (Ees) at pressure-volume relationship analysis versus T1 (both P < 0.05). Finally, at T3, when HDF misalignment and LV contractility reduction (GLS and Ees) were all restored, a rightward shift of the end-diastolic pressure-volume relationship (EDPVR) with an increase of ventricular capacitance was documented. In twin pregnancy, HDF misalignment in the first trimester precedes the slight temporary decrease in left ventricular systolic function in the second trimester; at the third trimester, a rightward shift of the EDPVR was associated with a realignment of HDF and normalization of ventricular contractility indexes. These coordinated changes that occur in the maternal heart during twin pregnancy suggest the role of HDFs in cardiac remodeling.NEW & NOTEWORTHY These changes indicate that 1) the misalignment of hemodynamic forces (HDFs) precedes a mild reduction in systolic function in twin pregnancy and 2) the positive left ventricular (LV) response to hemodynamic stress is mainly due to an improved diastolic function with enhanced LV cavity compliance.

Impact of left ventricular hemodynamic forces in adult patients with treated aortic coarctation and preserved left ventricular systolic function

BACKGROUND

The LV myocardial strain and hemodynamic forces (HDFs) are innovative markers of LV function. Aortic coarctation is safely repaired in infancy; however, mortality and morbidity remain increased in later life. The study investigated the role of left ventricular myocardial deformation and HDFs in asymptomatic patients who underwent successful aortic coarctation repair.

METHODS

Clinical and echocardiographic data were analyzed from 42 repaired CoA, 32 ± 20 years after surgery, 2D echocardiographic global longitudinal strain (GLS), circumferential strain (GCS) and HDFs were determined. CoA patients were compared with 42 patients affected by blood hypertension and 84 healthy controls; all matched for age and gender.

RESULTS

All groups had normal LV ejection fraction (LVEF), dimensions, and volumes. CoA patients showed a significantly higher rate of LV mass indexed (p < .001) and left atrial volumes indexed (p < .001). LV myocardial and endocardial global longitudinal and circumferential strain were decreased in CoA patients (p < .001, p < .001; p = .032 and p < .001, respectively). HDF parameters such as LV longitudinal force, LV systolic longitudinal force and LV impulse (LVim) were uniformly reduced (p = .006, p = .001, and p = .001, respectively). LV myocardial strain and HDF parameter values were independently associated with hospitalization for heart failure on univariable Cox regression analysis.

CONCLUSION

Despite preserved LVEF, patients with CoA had lower LV myocardial strain and HDF parameters values, independently associated with hospitalization for heart failure.

Evolution of Echocardiography-Derived Hemodynamic Force Parameters After Cardiac Resynchronization Therapy

Echocardiography-derived hemodynamic forces (HDF) allow calculation of intraventricular pressure gradients from routine transthoracic echocardiographic images. The evolution of HDF after cardiac resynchronization therapy (CRT) has not been investigated in large cohorts. The aim was to assess HDF in patients with heart failure implanted with CRT versus healthy controls. HDF were assessed before and 6 months after CRT. The following HDF parameters were calculated: (1) apical-basal strength, (2) lateral-septal strength, (3) the ratio of lateral-septal to apical-basal strength ratio, and (4) the force vector angle (1 and 2 representing the magnitude of HDF, 3 and 4 representing the orientation of HDF). In the propulsive phase of systole, the apical-basal impulse and the systolic force vector angle were measured. A total of 197 patients were included (age 64 ± 11 years, 62% male), with left ventricular ejection fraction ≤35%, QRS duration ≥130 ms and left bundle branch block. The magnitude of HDF was significantly lower and the orientation was significantly worse in patients with heart failure versus healthy controls. Immediately after CRT implantation, the apical-basal impulse and systolic force vector angle were significantly increased. Six months after CRT, improvement of apical-basal strength, lateral-septal to apical-basal strength ratio and the force vector angle occurred. When CRT was deactivated at 6 months, the increase in the magnitude of apical-basal HDF remained unchanged while the systolic force vector angle worsened significantly. In conclusion, HDF in CRT recipients reflect the acute effect of CRT and the effect of left ventricular reverse remodeling on intraventricular pressure gradients. Whether HDF analysis provides incremental value over established echocardiographic parameters, remains to be determined.

Haemodynamic forces predicting remodelling and outcome in patients with heart failure treated with sacubitril/valsartan

AIMS

A novel tool for the evaluation of left ventricular (LV) systo-diastolic function through echo-derived haemodynamic forces (HDFs) has been recently proposed. The present study aimed to assess the predictive value of HDFs on (i) 6 month treatment response to sacubitril/valsartan in heart failure with reduced ejection fraction (HFrEF) patients and (ii) cardiovascular events.

METHODS AND RESULTS

Eighty-nine consecutive HFrEF patients [70% males, 65 ± 9 years, LV ejection fraction (LVEF) 27 ± 7%] initiating sacubitril/valsartan underwent clinical, laboratory, ultrasound and cardiopulmonary exercise testing evaluations. Patients experiencing no adverse events and showing ≥50% reduction in plasma N-terminal pro-B-type natriuretic peptide and/or ≥10% LVEF increase over 6 months were considered responders. Patients were followed up for the composite endpoint of HF-related hospitalisation, atrial fibrillation and cardiovascular death. Forty-five (51%) patients were responders. Among baseline variables, only HDF-derived whole cardiac cycle LV strength (wLVS) was higher in responders (4.4 ± 1.3 vs. 3.6 ± 1.2; p = 0.01). wLVS was also the only independent predictor of sacubitril/valsartan response at multivariable logistic regression analysis [odds ratio 1.36; 95% confidence interval (CI) 1.10-1.67], with good accuracy at receiver operating characteristic (ROC) analysis [optimal cutpoint: ≥3.7%; area under the curve (AUC) = 0.736]. During a 33 month (23-41) median follow-up, a wLVS increase after 6 months (ΔwLVS) showed a high discrimination ability at time-dependent ROC analysis (optimal cut-off: ≥0.5%; AUC = 0.811), stratified prognosis (log-rank p < 0.0001) and remained an independent predictor for the composite endpoint (hazard ratio 0.76; 95% CI 0.61-0.95; p < 0.01), after adjusting for clinical and instrumental variables.

CONCLUSIONS

HDF analysis predicts sacubitril/valsartan response and might optimise decision-making in HFrEF patients.

CMR-derived left ventricular intraventricular pressure gradients identify different patterns associated with prognosis in dilated cardiomyopathy

AIMS

Left ventricular (LV) blood flow is determined by intraventricular pressure gradients (IVPG). Changes in blood flow initiate remodelling and precede functional decline. Novel cardiac magnetic resonance (CMR) post-processing LV-IVPG analysis might provide a sensitive marker of LV function in dilated cardiomyopathy (DCM). Therefore, the aim of our study was to evaluate LV-IVPG patterns and their prognostic value in DCM.

METHODS AND RESULTS

LV-IVPGs between apex and base were measured on standard CMR cine images in DCM patients (n = 447) from the Maastricht Cardiomyopathy registry. Major adverse cardiovascular events, including heart failure hospitalisations, life-threatening arrhythmias, and sudden/cardiac death, occurred in 66 DCM patients (15%). A temporary LV-IVPG reversal during systolic-diastolic transition, leading to a prolonged transition period or slower filling, was present in 168 patients (38%). In 14%, this led to a reversal of blood flow, which predicted outcome corrected for univariable predictors [hazard ratio (HR) = 2.57, 95% confidence interval (1.01-6.51), P = 0.047]. In patients without pressure reversal (n = 279), impaired overall LV-IVPG [HR = 0.91 (0.83-0.99), P = 0.033], systolic ejection force [HR = 0.91 (0.86-0.96), P < 0.001], and E-wave decelerative force [HR = 0.83 (0.73-0.94), P = 0.003] predicted outcome, independent of known predictors (age, sex, New York Heart Association class ≥ 3, LV ejection fraction, late gadolinium enhancement, LV-longitudinal strain, left atrium (LA) volume-index, and LA-conduit strain).

CONCLUSION

Pressure reversal during systolic-diastolic transition was observed in one-third of DCM patients, and reversal of blood flow direction predicted worse outcome. In the absence of pressure reversal, lower systolic ejection force, E-wave decelerative force (end of passive LV filling), and overall LV-IVPG are powerful predictors of outcome, independent of clinical and imaging parameters.

Effect of Aging on Intraventricular Kinetic Energy and Energy Dissipation

In recent years, analysis of kinetic energy (KE) and the rate of kinetic energy dissipation (KED) or energy loss (EL) within the cardiac chambers, obtained by cardiac imaging techniques, has gained increasing attention. Thus, there is a need to clarify the effect of physiological variables, specifically aging, on these energetic measures. To elucidate this aspect, we reviewed the literature on this topic. Overall, cardiac magnetic resonance and echocardiographic studies published so far indicate that aging affects the energetics of left and right intraventricular blood flow, although not all energy measures during the cardiac cycle seem to be affected by age in the same way. Current studies, however, have limitations. Additional large, multicenter investigations are needed to test the effect of physiological variables on intraventricular KE and KED/EL measures.

Acute Modification of Hemodynamic Forces in Patients with Severe Aortic Stenosis after Transcatheter Aortic Valve Implantation

Transcatheter aortic valve implantation (TAVI) is the established first-line treatment for patient with severe aortic stenosis not suitable for surgery. Echocardiographic evaluation of hemodynamic forces (HDFs) is a growing field, holding the potential to early predict improvement in LV function. A prospective observational study was conducted. Transthoracic echocardiography was performed before and after TAVI. HDFs were analyzed along with traditional left ventricular (LV) function parameters. Twenty-five consecutive patients undergoing TAVI were enrolled: mean age 83 ± 5 years, 74.5% male, mean LV Ejection Fraction (LVEF) at baseline 57 ± 8%. Post-TAVI echocardiographic evaluation was performed 2.4 ± 1.06 days after the procedure. HDF amplitude parameters improved significantly after the procedure: LV Longitudinal Forces (LF) apex-base [mean difference (MD) 1.79%; 95% CI 1.07-2.5; p-value < 0.001]; LV systolic LF apex-base (MD 2.6%; 95% CI 1.57-3.7; p-value < 0.001); LV impulse (LVim) apex-base (MD 2.9%; 95% CI 1.48-4.3; p-value < 0.001). Similarly, HDFs orientation parameters improved: LVLF angle (MD 1.5°; 95% CI 0.07-2.9; p-value = 0.041); LVim angle (MD 2.16°; 95% CI 0.76-3.56; p-value = 0.004). Conversely, global longitudinal strain and LVEF did not show any significant difference before and after the procedure. Echocardiographic analysis of HDFs could help differentiate patients with LV function recovery after TAVI from patients with persistent hemodynamic dysfunction.

Cardiovascular magnetic resonance-derived left ventricular intraventricular pressure gradients among patients with precapillary pulmonary hypertension

AIMS

Precapillary pulmonary hypertension (pPH) affects left ventricular (LV) function by ventricular interdependence. Since LV ejection fraction (EF) is commonly preserved, LV dysfunction should be assessed with more sensitive techniques. Left atrial (LA) strain and estimation of LV intraventricular pressure gradients (IVPG) may be valuable in detecting subtle changes in LV mechanics; however, the value of these techniques in pPH is unknown. Therefore, the aim of our study is to evaluate LA strain and LV-IVPGs from cardiovascular magnetic resonance (CMR) cines in pPH patients.

METHODS AND RESULTS

In this cross-sectional study, 31 pPH patients and 22 healthy volunteers underwent CMR imaging. Feature-tracking LA strain was measured on four- and two-chamber cines. LV-IVPGs (from apex-base) are computed from a formulation using the myocardial movement and velocity of the reconstructed 3D-LV (derived from long-axis cines using feature-tracking). Systolic function, both LV EF and systolic ejection IVPG, was preserved in pPH patients. Compared to healthy volunteers, diastolic function was impaired in pPH patients, depicted by (i) lower LA reservoir (36 ± 7% vs. 26 ± 9%, P < 0.001) and conduit strain (26 ± 6% vs. 15 ± 8%, P < 0.001) and (ii) impaired diastolic suction (-9.1 ± 3.0 vs. ‒6.4 ± 4.4, P = 0.02) and E-wave decelerative IVPG (8.9 ± 2.6 vs. 5.7 ± 3.1, P < 0.001). Additionally, 11 pPH patients (35%) showed reversal of IVPG at systolic-diastolic transition compared to none of the healthy volunteers (P = 0.002).

CONCLUSIONS

pPH impacts LV function by altering diastolic function, demonstrated by an impairment of LA phasic function and LV-IVPG analysis. These parameters could therefore potentially be used as early markers for LV functional decline in pPH patients.

500 HEMODYNAMIC FORCES AS PREDICTORS OF CARDIAC REMODELING AND OUTCOME IN PATIENTS WTH HEART FAILURE WITH REDUCED EJECTION FRACTION TREATED WITH SACUBITRIL/VALSARTAN

Aims

To evaluate the predictive value of echo-derived hemodynamic forces (HDF) compared to other echocardiographic, biohumoral and cardiopulmonary parameters on: a) angiotensin receptor-neprilysin inhibition (ARNI) response to 6-months treatment; b) cardiovascular events at follow-up.

Methods

Eighty-nine consecutive patients with heart failure with reduced ejection fraction (HFrEF) performed clinical, laboratory, ultrasound, and cardiopulmonary exercise testing. Patients experiencing no adverse events and showing ≥50% reduction in plasma N-terminal pro-B-type natriuretic peptide (NT-proBNP) and/or ≥10% increase in left ventricle ejection fraction over 6 months were considered responders to ARNI. We conducted a clinical follow-up for the composite endpoint of HF-related hospitalization, new-onset atrial fibrillation and cardiovascular death.

Results

Out of 89 patients, 45 (51%) were ARNI-responders. Among several variables evaluated at baseline, only the whole cardiac cycle left ventricle strength (wLVS) calculated from HDF was found to be higher in responders (4.4±1.3 vs 3.6±1.2; p=0.01) and the only independent predictor of ARNI-response at multivariate logistic regression analysis (odds ratio 1.36; 95% confidence interval 1.10–1.67; p=0.004), with good accuracy at receiver operating characteristic (ROC) analysis (optimal cut-off ≥3.7%; area under the curve [AUC]=0.736, 0.607–0.840; p&lt;0.0001). During a median follow-up of 33 months (interquartile range 23-41), 6-month wLVS increase (ΔwLVS) showed a high discrimination ability at time-dependent ROC analysis (optimal cut-off ≥0.5%; AUC=0.811, 0.69–0.90; p&lt;0.0001), stratified prognosis (log-rank p&lt;0.0001) and remained an independent prognostic predictor for the composite endpoint (hazard ratio 0.76, 0.61–0.95; p&lt;0.01), after adjusting for all clinical, functional and conventional echocardiographic parameters (Figure).

Conclusions

HDF analysis helps in predicting ARNI-response and optimizing follow-up and medical/device decision-making in patients with HFrEF.

Haemodynamic forces as predictors of cardiac remodelling and outcome in heart failure with reduced ejection fraction treated with sacubitril/valsartan

Background

Angiotensin receptor-neprilysin inhibitor (ARNI) is a cornerstone of treatment in heart failure (HF) with reduced ejection fraction (HFrEF), but its effectiveness shows interindividual differences.

Objectives

To evaluate the predictive value of echo-derived hemodynamic forces (HDF), together with other echocardiographic, biohumoral and cardiopulmonary parameters on a) response to ARNI after 6 months; b) adverse cardiovascular events at follow-up.

Methods

Eighty-nine consecutive HFrEF patients from two HF centers performed clinical evaluation, laboratory analyses, rest echocardiography and cardiopulmonary exercise testing. Response to ARNI at 6 months was considered in patients without HF admissions, death, or urgent heart transplant and with a ≥50% reduction in NT-proBNP levels and/or ≥10% increase in left ventricle ejection fraction. After 6 months, patients were followed up for a composite endpoint of cardiovascular death, HF-related hospitalization and new-onset atrial fibrillation.

Results

Response to ARNI was documented in 45/89 (51%) of patients. At baseline, responders and non-responders were paired in clinical assessment, conventional echocardiography, functional status and therapy. At multivariate logistic regression analysis, HDF-derived whole cardiac cycle left ventricle strength (wLVS) was the only independent predictor of ARNI response at 6 months (odds ratio 1.36, 95% confidence interval 1.10–1.67; p=0.004). A wLVS ≥3.7% showed a good accuracy in predicting ARNI response (AUC = 0.736, 0.607–0.840; p&lt;0.0001). During a median of 33 (IQR 23–41) months, wLVS increase from baseline to 6-month (ΔwLVS) showed a high discrimination ability at time-dependent ROC analysis (optimal cut-off: ≤0.5%; AUC=0.811, 0.69–0.90; p&lt;0.0001), stratified prognosis at Kaplan-Meier analysis (log-rank p&lt;0.0001), and remained an independent prognostic predictor of the composite endpoint (hazard ratio 0.76, 0.61–0.95; p&lt;0.01) even after adjusting for clinical, functional and conventional echocardiographic parameters.

Conclusions

HDF analysis may help predict ARNI response and optimize follow-up and medical/device strategies in patients with HfrEF.

Funding Acknowledgement

Type of funding sources: Public hospital(s). Main funding source(s): Fondazione Toscana Gabriele Monasterio, Pisa, Italy

CMR derived left ventricular intraventricular pressure gradients identify different patterns associated with prognosis in patients with dilated cardiomyopathy

Introduction

The direction of blood flow in the left ventricle (LV) is determined by intraventricular pressure gradients (IVPGs) between apex and base, which are altered when cardiac function declines. New cardiac magnetic resonance (CMR) post-processing software enables estimating LV-IVPGs. To date, the prognostic value of CMR derived IVPGs in patients with dilated cardiomyopathy (DCM) remains unknown.

Methods

DCM patients from the Maastricht Cardiomyopathy Registry, who underwent a CMR, were included. The software estimates the LV-IVPGs (between apex and base) by using the myocardial movement and velocity of a reconstructed 3D-LV model (derived from feature-tracking strain analysis of 2-, 3- and 4-chamber cine images). The primary outcome was a combined endpoint of heart failure (HF) hospitalisations, life-threatening arrhythmias and (sudden) cardiac death.

Results

In total, 447 DCM patients were included (age 55 interquartile range [46–63] years; 60% male). During a median follow-up of 6 [4–9] years, 66 patients (15%) reached the primary endpoint. In 168 patients (38%), a temporary pressure reversal from base-apex to apex-base during the systolic-diastolic transition was observed (figure). After correction for covariates that were univariably associated with outcome (p&lt;0.100, age, NYHA-class≥3, and left atrial (LA) conduit strain), flow reversal from base-apex to apex-base in the diastole was independently associated with outcome in the total cohort (HR 2.91, 95%-Confidence interval (95%-CI) [1.16–7.32], p=0.023; Table). In patients without pressure reversal (N=279) in the systolic-diastolic transition, IVPG during the total cardiac cycle (HR 0.88 [0.81–0.96], p=0.003), the systolic ejection force (HR 0.92 [0.87–0.97], p=0.003), and the E-wave decelerative force “C” (passive diastolic filling, HR 0.85 [0.74–0.97], p=0.013) were predictors of outcome, independent of other covariates (age, sex, NYHA class ≥3, LV ejection fraction, late gadolinium enhancement, LV longitudinal strain, LA volume index and LA conduit strain, table).

Conclusion

CMR-derived LV-IVPG analysis showed pressure reversal in the systolic-diastolic transition in one-third of DCM patients, and flow reversal was an independent predictor of worse outcome in these patients. In patients without this pressure reversal, LV-IVPG during the total cardiac cyle, the systolic ejection force, and the E-wave decelerative force were predictors of outcome, independent of all evauluated clinical and imaging parameters.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Netherlands Cardiovascular Research Initiative (initiative with support of the Dutch Heart Foundation) and CVON (She-PREDICTS, grant 2017-21 & CVON-DCVA Double Dosis 2021)

Abnormal Diastolic Hemodynamic Forces: A Link Between Right Ventricular Wall Motion, Intracardiac Flow, and Pulmonary Regurgitation in Repaired Tetralogy of Fallot

Background and Objective

The effect of chronic pulmonary regurgitation (PR) on right ventricular (RV) dysfunction in repaired Tetralogy of Fallot (RTOF) patients is well recognized by cardiac magnetic resonance (CMR). However, the link between RV wall motion, intracardiac flow and PR has not been established. Hemodynamic force (HDF) represents the global force exchanged between intracardiac blood volume and endocardium, measurable by 4D flow or by a novel mathematical model of wall motion. In our study, we used this novel methodology to derive HDF in a cohort of RTOF patients, exclusively using routine CMR imaging.

Methods

RTOF patients and controls with CMR imaging were retrospectively included. Three-dimensional (3D) models of RV were segmented, including RV outflow tract (RVOT). Feature-tracking software (QStrain 2.0, Medis Medical Imaging Systems, Leiden, Netherlands) captured endocardial contours from long/short-axis cine and used to reconstruct RV wall motion. A global HDF vector was computed from the moving surface, then decomposed into amplitude/impulse of three directional components based on reference (Apical-to-Basal, Septal-to-Free Wall and Diaphragm-to-RVOT direction). HDF were compared and correlated against CMR and exercise stress test parameters. A subset of RTOF patients had 4D flow that was used to derive vorticity (for correlation) and HDF (for comparison against cine method).

Results

68 RTOF patients and 20 controls were included. RTOF patients had increased diastolic HDF amplitude in all three directions (p<0.05). PR% correlated with Diaphragm-RVOT HDF amplitude/impulse (r = 0.578, p<0.0001, r = 0.508, p < 0.0001, respectively). RV ejection fraction modestly correlated with global HDF amplitude (r = 0.2916, p = 0.031). VO2-max correlated with Septal-to-Free Wall HDF impulse (r = 0.536, p = 0.007). Diaphragm-to-RVOT HDF correlated with RVOT vorticity (r = 0.4997, p = 0.001). There was no significant measurement bias between Cine-derived HDF and 4D flow-derived HDF by Bland-Altman analysis.

Conclusion

RTOF patients have abnormal diastolic HDF that is correlated to PR, RV function, exercise capacity and vorticity. HDF can be derived from conventional cine, and is a potential link between RV wall motion and intracardiac flow from PR in RTOF patients.

Cardiac and Vascular Remodeling After 6 Months of Therapy With Sacubitril/Valsartan: Mechanistic Insights From Advanced Echocardiographic Analysis

Background

Effects of Sacubitril/Valsartan (S/V) on left ventricular (LV) mechanics and ventricular-arterial coupling in patients with heart failure with reduced ejection fraction (HFrEF) are not completely understood. The aim of this study was to evaluate both cardiac and vascular remodeling in a group of HFrEF patients undergoing S/V therapy.

Methods

Fifty HFrEF patients eligible to start a therapy with S/V were enrolled. Echocardiographic evaluation was performed at baseline and after 6 months of follow-up (FU). Beside standard evaluation, including global longitudinal strain (GLS), estimated hemodynamic forces (HDFs) and non-invasive pressure-volume curves (PV loop) were assessed using dedicated softwares. HDFs were evaluated over the entire cardiac cycle, in systole and diastole, both in apex to base (A-B) and latero-septal (L-S) directions. The distribution of LV HDFs was evaluated by L-S over A-B HDFs ratio (L-S/A-B HDFs ratio). Parameters derived from estimated PV loop curves were left ventricular end-systolic elastance (E_es), arterial elastance (E_a), and ventricular-arterial coupling (VAC).

Results

At 6 months of FU indexed left ventricular end-diastolic and end-systolic volumes decreased (EDVi: 101 ± 28 mL vs. 86 ± 30 mL, p < 0.001; ESVi: 72 ± 23 mL vs. 55 ± 24 mL, p < 0.001), ejection fraction and GLS significantly improved (EF: 29 ± 6% vs. 37 ± 7%, p < 0.001; GLS: −9 ± 3% vs. −13 ± 4%, p < 0.001). A reduction of E_a (2.11 ± 0.91 mmHg/mL vs. 1.72 ± 0.44 mmHg/mL, p = 0.008) and an improvement of E_es (1.01 ± 0.37 mmHg/mL vs. 1.35 ± 0.6 mmHg/mL, p < 0.001) and VAC (2.3 ± 1.1 vs. 1.5 ± 0.7, p < 0.001) were observed. Re-alignment of HDFs occurred, with a reduction of diastolic L-S/A-B HDFs ratio [23 (20–35)% vs. 20 (11–28) %, p < 0.001].

Conclusion

S/V therapy leads to a complex phenomenon of reverse remodeling involving increased myocardial contractility, HDFs distribution improvement, and afterload reduction.

Left ventricle myocardial deformation in olympic athletes assessed by cardiac magnetic resonance: does the sex and discipline matter?

Funding Acknowledgements

Type of funding sources: None.

Background

Sport induces structural and functional cardiac adaptation with different entity related to several factors including type of training and gender. Cardiovascular Magnetic Resonance (CMR) is the gold standard for morpho-functional evaluation of athletes’ heart and commonly relies on ventricular volume, wall thickness and ejection fraction (EF) assessment. Data on myocardial deformation (MD) are limited to echocardiography and are scarce.

Purpose

To assess MD in Olympic athletes and to evaluate the possible influence of sport categories and gender.

Methods

A group of Olympic athletes evaluated prior the Olympic games with unremarkable cardiovascular pre-participation screening tests underwent CMR without contrast administration. A group of sedentary subjects was enrolled as a control group. Cine-images were post-processed for volume and function evaluation and to assess global longitudinal strain (GLS) and global circumferential strain (GCS) by feature-tracking software. Athletes were divided in subgroups according to ESC sport classification. Male and female athletes were compared. Athletes were also divided based on EF (≤53% or &gt;53%).

Results

93 elite athletes (33% power, 33% mixed, 33% endurance) and 18 controls were enrolled. No differences in terms of EF were observed, while endurance athletes showed the greater LV remodeling (Table). GLS and GCS values of the entire population were -22.5±2.7% and -30.7±3.4%, respectively. No significant differences were found comparing athletes of different sport categories and sedentary controls for GLS (p= 0.940) and GCS (p=0.072). Female athletes showed higher GLS compared to male (-23.5±2.8% vs-21.9±2.8%, p=0.002) but not differences in terms of GCS (-31.5±3.1% vs-30.2±3.5%, p=0.076). Athletes with EF≤53% had lower GLS values compared with those with &gt;53% but within normal limits (Figure).

Conclusion

No differences were observed in MD assessed by CMR between different sport categories and controls. Female athletes showed higher longitudinal but not circumferential strain compared with male. Athletes with lower EF presented lower values of strain but within normal range with the potentiality to be used as a tool for differential diagnosis between normal adaptation and disease.

Hemodynamic forces in olympic athletes assessed by cardiac magnetic resonance: a new non-invasive screening tool?

Funding Acknowledgements

Type of funding sources: None.

Background

Non-invasive evaluation of left ventricular hemodynamic forces (HDFs) by Cardiac Magnetic Resonance (CMR) is a promising tool to improve systolic and diastolic evaluation. No data are available on athletic population.

Purpose

To provide the range of normal values of HDFs in Olympic athletes and to evaluate the possible influence of different sport categories.

Methods

A group of Olympic athletes evaluated prior the Olympic games with unremarkable cardiovascular pre-participation screening tests underwent CMR without contrast administration. A group of sedentary subjects was enrolled as a control group. Cine-images were post-processed by a feature-tracking based software to estimate HDFs. HDFs were measured in apex-base (AB) and latero-septal (LS) directions, over the entire heartbeat, in systole and diastole. Athletes were divided in subgroups according to ESC sport classification for comparison. They were also divided according to the ejection fraction (EF ≤ or &gt;53%).

Results

93 elite athletes (33% power, 33% mixed, 33% endurance) were enrolled. HDFs in AB and LS direction were 20.5%± 4.3 and 2.9%± 0.7 in the entire heartbeat, 32.6% ± 7 and 3.6%± 1 in systole, 11%± 4.1 and 2.3%± 0.8 in diastole. Comparing athletes of different sport category and sedentary controls no significant differences were found between groups (Table). Comparing athletes with ejection fraction (EF) £ 53% and &gt; 53%, the former showed lower values of AB-HDFs assessed in the entire heartbeat and in systole (18.9 ± 4.6 % vs 20.9 ± 4.1; p= 0.024 and 29.6 ± 6.3 vs 33.3 ± 7; p= 0.024, respectively), but within the normal range.

Conclusion

We provide normal range for HDFs assessed by CMR in elite athletes and no differences were observed between sedentary controls and athletes involved in different sport categories. Comparing athletes with low-normal and normal ejection fraction, the former showed lower values of AB-HDFs but within the normal range.

Difference in cardiac remodeling between female athletes and pregnant women: a case control study

Objectives

The aim of this study was to detect possible differences in reversible cardiac remodeling occurring in sport training and twin pregnancy. Background: cardiac remodeling occurs in athletes and pregnant women due to training and fetal requirements, respectively. These changes could be apparently similar.

Methods

21 female elite athletes (23.2 ± 5.3 years), 25 women with twin pregnancies (35.4 ± 5.7 years) and 25 healthy competitive female athletes (controls), age-matched with pregnant women (34.9 ± 7.9 years), were enrolled. This latter group was included to minimize the effect of age on cardiac remodeling. All women evaluated through anamnestic collection, physical examination, 12 leads ECG, standard echocardiogram and strain analysis. Sphericity (SI) and apical conicity (ACI) indexes were also calculated.

Results

Pregnant women showed higher LA dimension (p < 0.001) compared to both groups of athletes. LV e RV GLS were significantly different in pregnant women compared to female athletes (p = 0.02 and 0.03, respectively). RV GLS was also different between pregnant women and controls (p = 0.02). Pregnant women showed significantly higher S′ wave compared to female athletes (p = 0.02) but not controls. Parameters of diastolic function were significantly higher in athletes (p = 0.08 for IVRT and p < 0.001 for E/A,). SI was lower in athletes in both diastole (p = 0.01) and systole (p < 0.001), while ACIs was lower in pregnant women (p = 0.04).

Conclusions

Cardiac remodeling of athletes and pregnant women could be similar at first sight but different in LV shape and in GLS, highlighting a profound difference in longitudinal deformation between athletes and pregnant women. This difference seems not to be related with age. These findings suggest that an initial maternal cardiovascular maladaptation could occur in the third trimester of twin pregnancies.

Cardio-vascular remodelling during sacubitril/valsartan therapy in patients with heart failure and reduced ejection fraction

Funding Acknowledgements

Type of funding sources: None.

Background

Sacubitril/valsartan (S/V) benefits in patients with heart failure and reduced ejection fraction (HFrEF) are partially related to cardiac reverse remodelling, in terms of volumes reduction and function improvement.  Effects on vascular remodeling are less investigated.

Purpose

To evaluate cardiac and vascular remodelling in a cohort of patients with HFrEF after six months of therapy with S/V.

Methods

50 patients with HFrEF eligible to start a therapy with sacubitril/valsartan were enrolled. Clinical evaluation and standard and advanced echocardiography were performed at baseline and after six months of follow up (FU). Standard left ventricular dimension and function parameters, global longitudinal strain (GLS) were calculated. Non-invasive pressure-volume curves (P-V loop) estimation was assessed with an off-line dedicated software using ST-E derived time-resolved LV volumes and brachial pressure as input. The following hemodynamic parameters were calculated based on P-V loop curves: left ventricular elastance (Ees), arterial elastance (Ea) and ventricular-arterial coupling (VAC).

Results

At six months F/U, a reduction of NYHA class in the vast majority of patients was detected (NYHA Class ≥ II, baseline vs F/U = 100% vs 50%; p&lt; 0,001). Systolic and diastolic blood pressure were lower, in comparison with baseline values (119 ± 16 vs 126  ± 11 mmHg; p = 0,002 and 71 ±  8 vs 78 ±  8 mmHg; p = 0,001, respectively). At echocardiographic evaluation, left ventricular end-diastolic and end-systolic volumes decreased (p&lt; 0.001 and p&lt; 0,001, respectively) and ejection fraction and GLS significantly improved (p&lt; 0.001 and p &lt; 0.001, respectively). Moreover, a significant reduction of Ea and a significant improvement of Ees and VAC were observed (p = 0.008, p&lt; 0,001 and p&lt; 0,001, respectively).

Conclusion

Therapy with S/V in HFrEF patients determines both cardiac and vascular remodelling reflecting the complex mechanisms behind clinical improvement. Abstract Figure.

Left ventricular forces distribution in patients with heart failure and reduced ejection fraction

Funding Acknowledgements

Type of funding sources: None.

Background

Hemodynamic forces (HDFs) are the forces exchanged between the blood and the myocardium. Estimation of their magnitude and alignment could be a novel marker of cardiac dysfunction.

Purpose

To describe left ventricular (LV) HDFs values and distribution in patients with heart failure with reduced ejection fraction (HFrEF) and to compare them with those of a group of healthy controls.

Methods

A cohort of 26 non-ischemic patients with an initial diagnosis of HFrEF was enrolled. All of them underwent basal 2D echocardiography evaluation.  Off-line HDFs estimation using a dedicated software based on speckle-tracking echocardiography was conducted. HDFs were normalized for the LV volume and expressed as a percentage of the force of gravity. HDFs were assessed over the entire cardiac cycle, in systole and diastole, both in apex to base (A-B) and latero-septal (L-S) directions. The distribution of LV HDFs was evaluated by L-S over A-B HDFs ratio (L-S/A-B HDFs ratio). HDFs of HFrEF patients were compared with those of 24 healthy volunteers.

Results

HFrEF patients showed smaller values of A-B HDFs during the entire cardiac cycle (5,2 ± 1,24% vs 12,3 ± 3,6%; p = 0,001), in systole (7,2 ± 2% vs 16,6 ± 6,3%; p = 0,001) and diastole (3,3 ± 0,8% vs 7,1 ± 3,6%; p = 0,001). Moreover, comparing HFrEF subjects with healthy volunteers , the former had lower L-S HDFs during the entire cardiac cycle (1,6 ± 0,4% vs 2 ± 0,7%; p= 0,022) and in systole (1,6 ± 0,5% vs 2,3 ± 0,8%; p = 0,003), while in diastole they showed inappropriate high values of L-S HDFs (1,7 ± 0,6% vs 1,8 ± 0,9%; p = 0,999). Consequently, HFrEF patients had higher  values of L-S/A-B ratio during the entire cardiac cycle (32 ± 6,9 vs 15 ± 7,7; p = 0,001), in systole (23,5 ± 7,4 vs 14,7± 4,2; p = 0,001), but particularly in diastole (52 ± 10,8 vs 28 ± 13,6; p = 0,001), showing an important HDFs misalignment.

Conclusion

When compared with healthy controls, HFrEF patients presented intraventricular fluid alterations characterized by lower HDFs magnitude and a significant HDFs misalignment, especially in diastole. Further studies are needed to confirm these initial results and to assess the effects of therapy on these new parameters. Abstract Figure.  Abstract Figure.

Impact of intraventricular haemodynamic forces misalignment on left ventricular remodelling after myocardial infarction

AIMS

Altered left ventricular (LV) haemodynamic forces (HDFs) have been associated with positive and negative remodelling after pathogenic or therapeutic events. We aimed to identify LV HDFs patterns associated with adverse LV remodelling (aLVr) in reperfused segment elevation myocardial infarction (STEMI) patients.

METHODS AND RESULTS

Forty-nine acute STEMI patients underwent cardiac magnetic resonance (CMR) at 1 week (baseline) and after 4 months (follow-up). LV HDFs were computed at baseline from cine CMR long axis data sets, using a novel technique based on endocardial boundary tracking, both in apex-base (A-B) and latero-septal (L-S) directions. HDFs distribution was evaluated by L-S over A-B HDFs ratio (L-S/A-B HDFs ratio %). HDFs parameters were computed over the entire heartbeat, in systole and diastole. At baseline, aLVr patients had lower systolic L-S HDF (2.7 ± 0.9 vs. 3.6 ± 1%; P = 0.027) and higher diastolic L-S/A-B HDF ratio (28 ± 14 vs. 19 ± 6%; P = 0.03). At univariate logistic regression analysis, higher infarct size [odds ratio (OR) 1.05; 95% confidence interval (CI) 1.01-1.1; P = 0.04], higher L-S/A-B HDFs ratio (OR 1.1; 95% CI 1.01-1.2; P = 0.05) and lower L-S HDFs (OR 0.41; 95% CI 0.2-0.9; P = 0.04) were associated with aLVr at follow-up. In the multivariable logistic regression analysis, diastolic L-S/A-B HDF ratio remained the only independent predictor of aLVr (OR 1.1; 95% CI 1.01-1.2; P = 0.04).

CONCLUSIONS

Misalignment of diastolic haemodynamic forces after STEMI is associated with aLVr after 4 months.

Introduction to Hemodynamic Forces Analysis: Moving Into the New Frontier of Cardiac Deformation Analysis

The potential relevance of blood flow for describing cardiac function has been known for the past 2 decades, but the association of clinical parameters with the complexity of fluid motion is still not well understood. Hemodynamic force (HDF) analysis represents a promising approach for the study of blood flow within the ventricular chambers through the exploration of intraventricular pressure gradients. Previous experimental studies reported the significance of invasively measured cardiac pressure gradients in patients with heart failure. Subsequently, advances in cardiovascular imaging allowed noninvasive assessment of pressure gradients during progression and resolution of ventricular dysfunction and in the setting of resynchronization therapy. The HDF analysis can amplify mechanical abnormalities, detect them earlier compared with conventional ejection fraction and strain analysis, and possibly predict the development of cardiac remodeling. Alterations in HDFs provide the earliest signs of impaired cardiac physiology and can therefore transform the existing paradigm of cardiac function analysis once implemented in routine clinical care. Until recently, the HDF investigation was possible only with contrast‐enhanced echocardiography and magnetic resonance imaging, precluding its widespread clinical use. A mathematical model, based on the first principle of fluid dynamics and validated using 4‐dimensional‐flow‐magnetic resonance imaging, has allowed HDF analysis through routine transthoracic echocardiography, making it more readily accessible for routine clinical use. This article describes the concept of HDF analysis and reviews the existing evidence supporting its application in several clinical settings. Future studies should address the prognostic importance of HDF assessment in asymptomatic patients and its incorporation into clinical decision pathways.

311 A new color Doppler-based echocardiographic technique for evaluation of intraventricular flow dynamics: first application to normal subjects, athletes, and patients

Aims

A new echocardiographic, color Doppler-based technique, named HyperDoppler, has been recently introduced for non-invasive evaluation of intracardiac flow dynamics. The aim of this study was to verify the feasibility and reproducibility of this technique and its capability to differentiate geometrical and energy measures of vortex flow within the left ventricle (LV) in normal subjects, athletes and patients with heart failure.

Methods and results

Two Italian cardiology centres enrolled each one 100 unselected, consecutive patients presenting at the echocardiography laboratory for a clinical examination, regardless of the indication to echocardiography. In these patients, the feasibility, repeatability, reproducibility, and inter-centre reproducibility of the HyperDoppler technique were tested using the intraclass correlation coefficient (ICC) and Bland–Altman analysis. In addition, 50 normal subjects, 30 professional athletes, and 50 patients with stabilized chronic heart failure and LV ejection fraction &lt;40% were enrolled. Images were acquired using a MyLab X8 echo-scanner and analysed to provide the following vortex flow measures: vortex area, normalized with the LV area; vortex intensity (i.e. the integral of the vorticity inside the vortex), normalized with the total vorticity; vortex depth (the distance of its centre from the LV base) and length along the base-apex direction, both normalized with the LV length; and the total kinetic energy dissipation (KED). Feasibility of HyperDoppler was very high (94.5%). According to the ICC values, at Centre 1 repeatability and reproducibility of vortex flow measures in unselected patients were good for vortex area (0.82, 0.85), length (0.83, 0.82) and depth (0.87, 0.84) and excellent for vortex intensity (0.92, 0.90) and KED (0.98, 0.98). Results of the Bland–Altman analysis showed no bias nor consistent under/overestimations of flow measures, with 95% of points always lying within the limits of agreement for each flow measure. Centre 2 provided similar repeatability and reproducibility evaluations for all the vortex measures, thus supporting a good-to-excellent inter-centre reproducibility. Athletes had greater vortex area, intensity, and KED compared to healthy subjects while they had smaller vortex length and depth and greater KED compared to patients with heart failure and reduced LV ejection fraction. In comparison with healthy subjects, heart failure patients showed greater vortex area, length, depth, and intensity but smaller KED. Combining vortex flow measures, the LV flow profile of healthy individuals, athletes, and heart failure patients could be differentiated.

Conclusions

HyperDoppler is a new ultrasound technique which is feasible, reliable, and practical for assessment of LV flow dynamics. It can quantitate several measures of the LV vortex and may distinguish normal subjects and patients. Future studies are needed to clarify how to implement this technique in cardiology clinical practice.

511 Cardio-vascular remodelling during sacubitril/valsartan therapy in patients with heart failure and reduced ejection fraction

Aims

Sacubitril/valsartan (S/V) benefits in patients with heart failure and reduced ejection fraction (HFrEF) are partially related to cardiac reverse remodelling, in terms of volumes reduction and function improvement. Effects on vascular remodelling are less investigated. To evaluate cardiac and vascular remodelling in a cohort of patients with HFrEF after 6 months of therapy with S/V.

Methods and results

50 patients with HFrEF eligible to start a therapy with sacubitril/valsartan were enrolled. Clinical evaluation and standard and advanced echocardiography were performed at baseline and after 6 months of follow-up (FU). Standard left ventricular dimension and function parameters and global longitudinal strain (GLS) were calculated. Non-invasive pressure-volume curves (P-V loop) estimation was assessed with an off-line dedicated software using ST-E derived time-resolved LV volumes and brachial pressure as input. The following haemodynamic parameters were calculated based on P–V loop curves: left ventricular elastance (Ees), arterial elastance (Ea), and ventricular-arterial coupling (VAC). At 6 months F/U, a reduction of NYHA class in the vast majority of patients was detected (NYHA Class ≥ II, baseline vs. F/U = 100% vs. 50%; P &lt; 0.001). Systolic and diastolic blood pressure were lower, in comparison with baseline values (119 ± 16 vs. 126 ± 11 mmHg; P = 0.002 and 71 ± 8 vs. 78 ± 8 mmHg; P = 0.001, respectively). At echocardiographic evaluation, left ventricular end-diastolic and end-systolic volumes decreased and ejection fraction and GLS significantly improved (Table). Moreover, a significant reduction of Ea and a significant improvement of Ees and VAC was observed (Table). 511 Table 1

Conclusions

Therapy with S/V in HFrEF patients determines both cardiac and vascular remodelling reflecting the complex mechanisms behind clinical improvement.

Home-based exercise program improves normal Right Ventricle function in Renal Transplant Recipients

BACKGROUND

Right ventricular function is strongly associated with clinical outcomes in populations at high cardiovascular risk. Renal Transplant Recipients have multiple coexisting comorbidities potentially involved in the biventricular dysfunction including the right ventricular chamber. Speckle tracking echocardiography is recently used to investigate the normal function of this chamber. The study aims to verify whether global longitudinal strain carries clinical and prognosis implications in the renal transplant recipients during 1 year of regular unsupervised physical activity and compared to a control group.

METHODS

a group of 50 transplant recipients, aged 49.6±11.5 was submitted for 1 year to a moderate intensity of mixed exercise. All the subjects were followed by echocardiographic exam every 6 months, only 25 subjects with a high quality of image were investigated by 2D Speckle tracking strain analysis with the measurement calculated at T0, T6, and T12 months.

RESULTS

renal transplant recipients started with low values of right ventricle global longitudinal strain compared to health controls; it increased significantly (p<0.01) after 12 months of exercise, restoring the normal range.

CONCLUSIONS

moderate intensity of physical exercise, despite unsupervised, support a normal RV ventricular performance in renal transplant recipients. strain analysis contribute to plan a correct follow-up, with prognostic impact in these patients practicing physical exercise.

A Novel Approach to Left Ventricular Filling Pressure Assessment: The Role of Hemodynamic Forces Analysis

Background: Diastolic function in patients with heart failure is usually impaired, resulting in increased left ventricular (LV) filling pressures, whose gold standard assessment is right heart catheterization (RHC). Hemodynamic force (HDF) analysis is a novel echocardiographic tool, providing an original approach to cardiac function assessment through the speckle-tracking technology. The aim of our study was to evaluate the use of HDFs, both alone and included in a new predictive model, as a potential novel diagnostic tool of the diastolic function.

Methods: HDF analysis was retrospectively performed in 67 patients enrolled in the “Right1 study.” All patients underwent RHC and echocardiography up to 2 h apart. Increased LV filling pressure (ILFP) was defined as pulmonary capillary wedge pressure (PCWP) ≥ 15 mmHg.

Results: Out of 67 patients, 33 (49.2%) showed ILFP at RHC. Diastolic longitudinal force (DLF), the mean amplitude of longitudinal forces during diastole, was associated with the presence of ILFP (OR = 0.84 [0.70; 0.99], p = 0.046). The PCWP prediction score we built including DLF, ejection fraction, left atrial enlargement, and e' septal showed an AUC of 0.83 [0.76–0.89], with an optimal internal validation. When applied to our population, the score showed a sensitivity of 72.7% and a specificity of 85.3%, which became 66.7 and 94.4%, respectively, when applied to patients classified with “indeterminate diastolic function” according to the current recommendations.

Conclusion: HDF analysis could be an additional useful tool in diastolic function assessment. A scoring system including HDFs might improve echocardiographic accuracy in estimating LV filling pressures. Further carefully designed studies could be useful to clarify the additional value of this new technology.

Comparative Analysis of Right Ventricle Fluid Dynamics

The right and left sides of the human heart operate with a common timing and pump the same amount of blood. Therefore, the right ventricle (RV) presents a function that is comparable to the left ventricle (LV) in terms of flow generation; nevertheless, the RV operates against a much lower arterial pressure (afterload) and requires a lower muscular strength. This study compares the fluid dynamics of the normal right and left ventricles to better understand the role of the RV streamlined geometry and provide some physics-based ground for the construction of clinical indicators for the right side. The analysis is performed by image-based direct numerical simulation, using the immersed boundary technique including the simplified models of tricuspid and mitral valves. Results demonstrated that the vortex formation process during early diastole is similar in the two ventricles, then the RV vorticity rapidly dissipates in the subvalvular region while the LV sustains a weak circulatory pattern at the center of the chamber. Afterwards, during the systolic contraction, the RV geometry allows an efficient transfer of mechanical work to the propelled blood; differently from the LV, this work is non-negligible in the global energetic balance. The varying behavior of the RV, from reservoir to conduct, during the different phases of the heartbeat is briefly discussed in conjunction to the development of possible dysfunctions.

The hemodynamic power of the heart differentiates normal from diseased right ventricles

Cardiac mechanics is primarily described by the pressure-volume relationship. The ventricular pressure-volume loop displays the instantaneous relationship between intraventricular pressure and volume throughout the cardiac cycle; however, it does not consider the shape of the ventricles, their spatiotemporal deformation patterns, and how these balance with the flowing blood. Our study demonstrates that the pressure-volume relationship represents a first level of approximation for the mechanical power of the ventricles, while, at a further level of approximation, the importance of hemodynamic power emerges through the balance between deformation patterns and fluid dynamics. The analysis is preliminarily tested in a healthy subject's right ventricle and two patients. Moreover, patients' geometry was then rescaled to present a normal volumetric profile to verify whether results were affected by volume size or by the spatiotemporal pattern of how that volume profile was achieved. Results show that alterations of hemodynamic power were found in the abnormal ventricles and that they were not directly caused by the ventricular size but by changes in the ability of intraventricular pressure gradient to generate blood flow. Therefore, hemodynamic power represents a physics-based measure that takes into account the dynamics of the space-time shape changes in combination with blood flow. Hemodynamic power is assessed non-invasively using cardiac imaging techniques and can be an early indicator of cardiac dysfunction before changes occur in volumetric measurements. These preliminary results provide a physical ground to evaluate its diagnostic or prognostic significance in future clinical studies.

Left ventricular force adaptation and cardiac deformation in the progression of aortic stenosis

Funding Acknowledgements

Type of funding sources: None.

Introduction. Aortic stenosis (AS) is one of the most common valvular heart diseases; however, the association between left ventricular (LV) myocardial deformation and hemodynamic forces (HDFs) is still mostly  unexplored.

Purpose. This study aimed to assess the differences in LV myocardial deformation and HDFs in a large cohort of patients with aortic stenosis retrospectively.

Methods. Two-hundred fifty-four subjects (median age 77 years, 50% women) with preserved LV ejection fraction (LVEF), and mild (n = 87), moderate (n = 92) or severe (n = 75) AS, were included in the study. The 2D LV global longitudinal strain (GLS), circumferential strain (GCS), and HDFs were measured with new software that allowed us to calculate all these values and parameters from the three apical views.

Results. When comparing severe AS to mild AS, LV mass appeared increased while the LV hypertrophy phenotype was concentric (p &lt;0.0001). Along with the progression of the AS, LVEF was decreased. All GLS, GCS, and HDFs parameters were uniformly reduced in severe AS compared to mild AS (p &lt;0.0001), in the same way, LV longitudinal force, LV longitudinal systolic force, and LV impulse have proven to be accurate on ROC curves (AUC 70%, 73% and 73% respectively).

Conclusion. The integrated approach of deformation and cardiac mechanics allows the description of pathophysiological changes during the progression of mild to severe aortic stenosis.

Abstract Figure. Strain parameters and aortic stenosis

Misalignment of hemodynamic forces in the left ventricle is associated with adverse remodeling following STEMI

Funding Acknowledgements

Type of funding sources: None.

Background

Infarct size (IS), area at risk (AAR) and microvascular obstruction (MVO) are well known predictors of adverse remodeling (aLVr) following acute myocardial infarction, while the pathogenic role of left ventricular (LV) hemodynamic forces (HDFs) is still unknown. Recent evidence suggests the role of HDFs in negative remodeling after pathogenic events. 

Purpose

To identify LV HDFs patterns associated with aLVr in reperfused ST-segment elevation MI (STEMI) patients.

Methods

Forty-nine acute STEMI patients underwent CMR at 1 week (baseline) and 4 months (follow-up) after MI.  The following parameters were measured: left ventricular end-diastolic and end-systolic volume index for body surface area (LVEDVi and LVESVi), left ventricular ejection fraction (LVEF) and LV mass index, AAR and IS. LV HDFs were computed at baseline from cine CMR long axis datasets using a novel method based on LV endocardial boundary tracking. LV HDFs were calculated both in apex-base (A-B) and latero-septal (L-S) directions. The distribution of LV HDFs were evaluated by L-S over A-B HDFs ratio (L-S/A-B HDFs ratio %). All HDFs parameters are computed over the entire heartbeat, in systole and diastole. aLVr was defined as an absolute increase in LVESV of at least 15% (ΔLV-ESV ≥15%).

Results

Patients with aLVr (n = 18; 37%) had significant greater value of AAR (32 ± 23 vs 22 ± 18; p = 0.03) and slightly larger IS (23 ± 16 vs 15 ± 11; p= 0.07) at baseline. In patients with aLVr at FU, baseline systolic L-S HDF were lower (2.7 ± 0.9 vs 3.6 ± 1; p = 0.027) while diastolic L-S/A-B HDF ratio was significantly higher (28 ± 14 vs 19 ± 6; p = 0.03), reflecting higher grade of diastolic HDFs misalignment. At univariate logistic regression analysis, higher IS [Odd ratio (OR) 1.05; 95% confidence interval (95% CI) 1.01-1.1; p= 0.04] L-S HDFs (OR 0.41; 95% CI 0.2-0.9; p= 0.04] and higher diastolic L-S/A-B HDFs ratio (OR 1.1; 95% CI 1.01-1.2; p= 0.05) were associated with aLVr at FU (Table).  At multivariate logistic regression analysis, L-S/A-B HDF ratio remained the only independent predictor of adverse LV remodeling after correction for other baseline determinants.

Conclusion

Misalignment of diastolic HDFs following STEMI is associated with aLVr observed after 4 months.

Predictors of adverse remodeling Univariate Multivariate Parameter OR (95% CI) P OR (95% CI) P IS (%) 1.05 (1.01-1.1) 0.042 - - Systolic L-S HDF 0.41 (0.2-0.9) 0.04 - - Diastolic L-S/A-B HDF Ratio 1.1 (1.01-1.2) 0.05 1.1 (1.01-1.2) 0.04 A-B:apex-base; L-S: latero-septal; HDFs: hemodynamic forces Abstract Figure. Diastolic HDFs distribution and aLVr

Impact of synchronous atrioventricular delay optimization on left ventricle flow force angle evaluated by echocardiographic particle image velocimetry

PURPOSE

To evaluate the improvement in electrical synchrony and left ventricle (LV) hemodynamics provided by combining the dynamic atrioventricular delay (AVD) of SyncAV^TM CRT and the multiple LV pacing sites of MultiPoint pacing (MPP).

METHODS

Patients with LBBB and QRS duration (QRSd) > 140 ms implanted with a CRT-D or CRT-P device and quadripolar LV lead were enrolled in this prospective study. During a post-implant follow-up visit, QRSd was measured from 12-lead surface electrograms by experts blinded to pacing configurations. QRSd reduction relative to intrinsic rhythm was evaluated during biventricular pacing (BiV) and MPP for two AVDs: nominal (140/110 ms paced/sensed) and SyncAV (patient-optimized SyncAV offset [10-60 ms] minimizing QRSd). Echocardiography particle imaging velocimetry (Echo-PIV) analysis was performed for each configuration. The resulting hemodynamic force LV flow angle (φ) was analyzed, which ranges from 0^o (predominantly base-apex forces) to 90^o (predominantly transverse forces). Higher angles indicate more energy dissipation at lateral walls due to transverse flow; lower angles indicate healthier flow aligned with the longitudinal base-apex path of the pressure gradient.

RESULTS

Twelve patients (58% male, 17% ischemic, 32±7% ejection fraction, 165 ± 18 ms intrinsic QRSd) completed QRSd and Echo-PIV assessment. Relative to intrinsic rhythm, BiV and MPP with nominal AVD reduced QRSd by 10 ± 9% and 12 ± 9%, respectively. BiV+SyncAV and MPP+SyncAV further reduced QRSd by 19 ± 8%, (p < 0.05 vs. BiV with nominal AVD) and 23 ± 9% (p < 0.05 vs BiV+SyncAV), respectively. Echo-PIV showed similar sequential hemodynamic improvements. LV flow angular orientation during intrinsic activation (46 ± 3^o) reduced with BiV+SyncAV (37 ± 4^o, p < 0.05 vs intrinsic) and further with MPP+SyncAV (34 ± 4^o, p < 0.05 vs BiV+SyncAV).

CONCLUSION

These results suggest that SyncAV may improve electrical synchrony and influence LV flow patterns in patients suffering from heart failure compared to conventional CRT with a fixed AVD, with further improvement observed by combining with MPP.

A new integrated approach to cardiac mechanics: reference values for normal left ventricle

The association between left ventricular (LV) myocardial deformation and hemodynamic forces is still mostly unexplored. The normative values and the effects of demographic and technical factors on hemodynamic forces are not known. The authors studied the association between LV myocardial deformation and hemodynamic forces in a large cohort of healthy volunteers. One-hundred seventy-six consecutive subjects (age range, 16-82; 51% women), with no cardiovascular risk factors or any relevant diseases, were enrolled. All subjects underwent an echo-Doppler examination. Both 2D global myocardial and endocardial longitudinal strain (GLS), circumferential strain (GCS), and the hemodynamic forces were measured with new software that enabled to calculate all these values and parameters from the three apical views. Higher LV mass index and larger LV volumes were found in males compared to females (85 ± 17 vs 74 ± 15 g/m² and 127 ± 28 vs 85 ± 18 ml, p < 0.0001 respectively) while no differences of the mean values of endocardial and myocardial GLS and of myocardial GCS were found (p = ns) and higher endocardial GCS in women (- 30.6 ± 4.2 vs - 31.8 ± 3.7; p = 0.05). LV longitudinal force, LV systolic longitudinal force and LV impulse were higher in men (16.2 ± 5.3 vs 13.2 ± 3.6; 25.1 ± 7.9 vs 19.4 ± 5.6 and 20.4 ± 7 vs 16.6 ± 5.2, p < 0.0001, respectively). A weak but statistically significant decline with age (p < 0.0001) was also found for these force parameters. This new integrated approach could differentiate normality from pathology by providing average deformation values and hemodynamic forces parameters, differentiated by age and gender.

P737 Left ventricular hemodynamic forces: towards establishing reference values for healthy adults

Introduction

Left ventricular hemodynamic forces (LV-HDF) have been recently demonstrated to be promising markers of sub-clinical dysfunction and potential predictors of disease outcome. However, there is a lack of reference values in healthy subjects. Knowledge of physiologic ranges is mandatory towards the use of LV-HDF-based indices for disease assessment in future clinical applications.

Purpose

Aim of the current study is to define the normal reference values for LV-HDF parameters in a large cohort of healthy adults. Here we present preliminary results for the initial set of enrolled subjects.

Methods

We enrolled 82 healthy subjects [mean age 44 ± 13.2 years (range 18-88), 41 men]. All participants underwent standard transthoracic echocardiography (TTE) examination, as recommended by current guidelines, including apical two-, three- and four-chamber windows, acquired at a frame rate above 40 Hz. These were then analyzed by tri-plane tissue tracking, measuring LV volume and LV ejection fraction (EF) as reference parameters. The same tracking method was used to evaluate the global hemodynamic force by a novel mathematical calculation technique applied to the three-dimensional endocardial contour. Physical-based LV-HDF parameters were then extracted for clinical application; these included the amplitude (root mean square) of the longitudinal and transversal force components (FL and FT) and their alignment angle relative to the LV axis. Parameters were computed as average over the whole cardiac cycle as well as limited to the systolic phase. Forces were normalized with LV volume to reduce variability with LV dimension, and divided by specific weight to yield a dimensionless measure.

Results

Mean EF was 63 ± 9%. Whole cycle LV-HDF parameters were: FL = 16.0 ± 5.6%, FT = 2.3 ± 0.8%, with significant longitudinal alignment FT/FL = 0.15 ± 0.04, angle = 13.0°±3.1°. Systolic HDF parameters were: FL = 22.7 ± 8.2%, FT = 2.9 ± 1.1%, with longitudinal alignment FT/FL = 0.13 ± 0.04, angle = 11.2°±3.1°. Importantly, dimensionless physical-based LV-HDF parameters showed no significant variation with age, gender or BSA.

Conclusions

We report the physiologic range of LV-HDF parameters measured by TTE. Knowledge of age- and gender-specific reference values, for a combination of standard, mechanical and hemodynamic indices, can improve the global assessment of the LV function and may help to detect sub-clinical stages of LV dysfunction.

P795 Intraventricular fluid patterns during dobutamine stress echo in patients with significant coronary stenosis

Background

Dobutamine stress echo (DSE) is a useful tool for the evaluation of patients with suspected stable coronary artery disease (CAD). There has been no detailed investigation about the effects of exercise or pharmacological stress on intraventricular fluid dynamics. The possible association between significant CAD and abnormal fluid patterns has not been studied yet.

Purpose

Aim of the study was to evaluate the intraventricular vortices during dobutamine stress and to find fluid-dynamic patterns associated with the presence of significant CAD.

Methods

36 patients scheduled for coronary angiography (CA) and with clinical indication for DSE for suspected CAD were enrolled. Each patient underwent 2D, 3D and contrast echocardiography for Echo-PIV analysis and vortex quantification, both at rest and at peak stress. Vortex geometric and energetic parameters were evaluated using a post- processional software. Intraventricular pressure gradients were evaluated as well. Positive CA for significant CAD was defined as the presence of at least one epicardial coronary stenosis with ≥70% luminal narrowing.

Result

CA was positive in 58% of patients while DSE in 33%. In the whole population, at peak stress a reduction in vortex area (from 0.36 ± 0.01 to 0.21 ± 0.02; p= 0.001) and in absolute value of vortex intensity (from 0.36 ± 0.1 to 0.26 ± 0.12; p= 0.001) were detected. Vorticity fluctuation and kinetic energy (KE) fluctuation showed a significant increment at peak stress (respectively 0.84 ± 0.17 to 0.93 ± 0.07; p= 0.005; from 1.76 ± 0.37 to 2.47 ± 0.82; p= 0.001), as well as a deviation of flow force momentum angle (φ: from 36 ± 8 to 44 ±9; p= 0.001). Patients with positive CA showed during DSE an higher decrease of the absolute value of vortex intensity (Δ% |vortex intensity| -1.7 ± 0.39 vs -1.3 ± 0.56 vs; p= 0.021), and higher increase of flow force angle (Δ% φ 0.48 ± 0.6 vs 0.1 ± 0.27; p= 0.042). A reversal in the main direction of the vortical flow occurred in 9 patients (25%) at peak stress and 7 of them (64%) were found to have significant right coronary stenosis. This unexpected change in the vortical flow and the presence of right coronary artery stenosis were found significantly associated (X2 p= 0,02). Moreover, patients with circumflex artery stenosis were less likely to have a decrease of vortex length at peak stress (Δ% Vortex length - 0,06 ± 0, 36 vs - 0,34 ± 0,28, p= 0,034).

Conclusion

Significant changes in intraventricular vortices occur during DSE. The presence of significant CAD evaluated with CA was associated with different behavior of fluid dynamics during DSE. Further studies are needed to assess normal and pathological intraventricular flow patterns evaluated during DSE.

Abstract P795 Figure. Vortex reversal at peak stress

Combined flow-based imaging assessment of optimal cardiac resynchronization therapy pacing vector: a case report

Background

There are still many pendent issues about the effective evaluation of cardiac resynchronization therapy impact on functional mitral regurgitation. In order to reduce the intrinsic difficulties of quantification of functional mitral regurgitation itself, an automatic quantification of real-time three-dimensional full-volume color Doppler transthoracic echocardiography was proposed as a new, rapid, and accurate method for the assessment of functional mitral regurgitation severity. Recent studies suggested that images of left ventricle flow by echo-particle imaging velocimetry could be a useful marker of synchrony. Echo-particle imaging velocimetry has shown that regional anomalies of synchrony/synergy of the left ventricle are related to the alteration, reduction, or suppression of the physiological intracavitary pressure gradients.

Case summary

We describe a case in which the two technologies are used in combination during acute echocardiographic optimization of left pacing vector in a 63-year-old man, Caucasian, who showed worsening heart failure symptoms a few days after an implant, and the effect of the device’s optimization at 6-month follow-up.

Discussion

The degree of realignment of hemodynamic forces, with quantitative analysis of the orientation of blood flow momentum (φ), can represent improvement of fluid dynamics synchrony of the left ventricle, and explain, with a new deterministic parameter, the effects of cardiac resynchronization therapy on functional mitral regurgitation. Real-time three-dimensional color flow Doppler quantification is feasible and accurate for measurement of mitral inflow, left ventricular outflow stroke volumes, and functional mitral regurgitation severity.

Conclusion

This clinical case offers an innovative and accurate approach for acute echocardiographic optimization of left pacing vector. It shows clinical utility of combined three-dimensional full-volume color Doppler transthoracic echocardiography/echo-particle imaging velocimetry assessment to increase response to cardiac resynchronization therapy, in terms of reduction of functional mitral regurgitation, improving fluid dynamics synchrony of the left ventricle.

Electronic supplementary material

The online version of this article (10.1186/s13256-019-2048-1) contains supplementary material, which is available to authorized users.

Range Variability in CMR Feature Tracking Multilayer Strain across Different Stages of Heart Failure

Heart failure (HF) is associated with progressive ventricular remodeling and impaired contraction that affects distinctly various regions of the myocardium. Our study applied cardiac magnetic resonance (CMR) feature tracking (FT) to assess comparatively myocardial strain at 3 distinct levels: subendocardial (Endo-), mid (Myo-) and subepicardial (Epi-) myocardium across an extended spectrum of patients with HF. 59 patients with HF, divided into 3 subgroups as follows: preserved ejection fraction (HFpEF, N = 18), HF with mid-range ejection fraction (HFmrEF, N = 21), HF with reduced ejection fraction (HFrEF, N = 20) and a group of age- gender- matched volunteers (N = 17) were included. Using CMR FT we assessed systolic longitudinal and circumferential strain and strain-rate at Endo-, Myo- and Epi- levels. Strain values were the highest in the Endo- layer and progressively lower in the Myo- and Epi- layers respectively, this gradient was present in all the patients groups analyzed but decreased progressively in HFmrEF and further on in HFrEF groups. GLS decreased with the severity of the disease in all 3 layers: Normal > HFpEF > HFmrEF > HFrEF (Endo-: −23.0 ± 3.5 > −20.0 ± 3.3 > −16.4 ± 2.2 > −11.0 ± 3.2, p < 0.001, Myo-: −20.7 ± 2.4 > −17.5.0 ± 2.6 > −14.5 ± 2.1 > −9.6 ± 2.7, p < 0.001; Epi-: −15.7 ± 1.9 > −12.2 ± 2.1 > −10.6 ± 2.3 > −7.7 ± 2.3, p < 0.001). In contrast, GCS was not different between the Normal and HFpEF (Endo-: −34.5 ± 6.2 vs −33.9 ± 5.7, p = 0.51; Myo-: −21.9 ± 3.8 vs −21.3 ± 2.2, p = 0.39, Epi-: −11.4 ± 2.0 vs −10.9 ± 2.3, p = 0.54) but was, as well, markedly lower in the systolic heart failure groups: Normal > HFmrEF > HFrEF (Endo-: −34.5 ± 6.2 > −20.0 ± 4.2 > 12.3 ± 4.2, p < 0.001; Myo-: −21.9 ± 3.8 > −13.0 ± 3.4 > −8.0 ± 2.7. p < 0.001; Epi-: −11.4 ± 2.0 > −7.9 ± 2.3 > −4.5 ± 1.9. p < 0.001). CMR feature tracking multilayer strain assessment identifies large range differences between distinct myocardial regions. Our data emphasizes the importance of sub-endocardial myocardium for cardiac contraction and thus, its predilect role in imaging detection of functional impairment. CMR feature tracking offers a convenient, readily available, platform to evaluate myocardial contraction with excellent spatial resolution, rendering further details about discrete areas of the myocardium. Using this technique across distinct groups of patients with heart failure (HF), we demonstrate that subendocardial regions of the myocardium exhibit much higher strain values than mid-myocardium or subepicardial and are more sensitive to detect contractile impairment. We also show comparatively higher values of circumferential strain compared with longitudinal and a higher sensitivity to detect contractile impairment. A newly characterized group of patients, HF with mid-range ejection fraction (EF), shows similar traits of decompensation but has relatively higher strain values as patients with HF with reduced EF.

Assessment of Global Longitudinal and Circumferential Strain Using Computed Tomography Feature Tracking: Intra-Individual Comparison with CMR Feature Tracking and Myocardial Tagging in Patients with Severe Aortic Stenosis

In this study, we used a single commercially available software solution to assess global longitudinal (GLS) and global circumferential strain (GCS) using cardiac computed tomography (CT) and cardiac magnetic resonance (CMR) feature tracking (FT). We compared agreement and reproducibility between these two methods and the reference standard, CMR tagging (TAG). Twenty-seven patients with severe aortic stenosis underwent CMR and cardiac CT examinations. FT analysis was performed using Medis suite version 3.0 (Leiden, The Netherlands) software. Segment (Medviso) software was used for GCS assessment from tagged images. There was a trend towards the underestimation of GLS by CT-FT when compared to CMR-FT (19.4 ± 5.04 vs. 22.40 ± 5.69, respectively; p = 0.065). GCS values between TAG, CT-FT, and CMR-FT were similar (p = 0.233). CMR-FT and CT-FT correlated closely for GLS (r = 0.686, p < 0.001) and GCS (r = 0.707, p < 0.001), while both of these methods correlated moderately with TAG for GCS (r = 0.479, p < 0.001 for CMR-FT vs. TAG; r = 0.548 for CT-FT vs. TAG). Intraobserver and interobserver agreement was excellent in all techniques. Our findings show that, in elderly patients with severe aortic stenosis (AS), the FT algorithm performs equally well in CMR and cardiac CT datasets for the assessment of GLS and GCS, both in terms of reproducibility and agreement with the gold standard, TAG.

Analysis of mitral valve regurgitation by computational fluid dynamics

The clinical syndrome of mitral insufficiency is a common consequence of mitral valve (MV) prolapse, when the MV leaflets do not seal the closed orifice and blood regurgitates back to the atrium during ventricular contraction. There are different types of MV prolapse that may influence the degree of regurgitation also in relation to the left ventricle (LV) geometry. This study aims to provide some insight into the fluid dynamics of MV insufficiency in view of improving the different measurements available in the clinical setting. The analysis is performed by a computational fluid dynamics model coupled with an asymptotic model of the MV motion. The computational fluid dynamics solution uses the immersed boundary method that is efficiently integrated with clinical imaging technologies. Healthy and dilated LVs obtained by multislice cardiac MRI are combined with simplified models of healthy and pathological MVs deduced from computed tomography and 4D-transesophageal echocardiography. The results demonstrated the properties of false regurgitation, blood that did not cross the open MV orifice and returns into the atrium during the backward motion of the MV leaflets, whose entity should be accounted when evaluating small regurgitation. The regurgitating volume is found to be proportional to the effective orifice area, with the limited dependence of the LV geometry and type of prolapse. These affect the percentage of old blood returning to the atrium which may be associated with thrombogenic risk.

Intraventricular flow patterns during right ventricular apical pacing

Objectives

To assess differences in blood flow momentum (BFM) and kinetic energy (KE) dissipation in a model of cardiac dyssynchrony induced by electrical right ventricular apical (RVA) stimulation compared with spontaneous sinus rhythm.

Methods

We cross-sectionally enrolled 12 consecutive patients (mean age 74±8 years, 60% male, mean left ventricular ejection fraction 58%±6 %), within 48 hours from pacemaker (PMK) implantation. Inclusion criteria were: age>18 years, no PMK-dependency, sinus rhythm with a spontaneous narrow QRS at the ECG, preserved ejection fraction (>50%) and a low percentage of PMK-stimulation (<20%). All the participants underwent a complete echocardiographic evaluation, including left ventricular strain analysis and particle image velocimetry.

Results

Compared with sinus rhythm, BFM shifted from 27±3.3 to 34±7.6° (p=0.016), while RVA-pacing was characterised by a 35% of increment in KE dissipation, during diastole (p=0.043) and 32% during systole (p=0.016). In the same conditions, left ventricle global longitudinal strain (LV GLS) significantly decreased from 17±3.3 to 11%±2.8% (p=0.004) during RVA-stimulation. At the multivariable analysis, BFM and diastolic KE dissipation were significantly associated with LV GLS deterioration (Beta Coeff.=0.54, 95% CI 0.07 to 1.00, p=0.034 and Beta Coeff.=0.29, 95% CI 0.02 to 0.57, p=0.049, respectively).

Conclusions

In RVA-stimulation, BFM impairment and KE dissipation were found to be significantly associated with LV GLS deterioration, when controlling for potential confounders. Such changes may favour the onset of cardiac remodelling and sustain heart failure.