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The objective of the current study is to assess the feasibility of using a left ventricle (LV) model in order to reproduce myocardial strains in the case of ischemic heart disease (IHD). The proposed integrated LV model couples a finite element method (FEM) sub-model of the cardiac electrical activity, representing the propagation of the transmembrane potential through the LV, a FEM sub-model of the cardiac mechanical activity, and a lumped-parameter model of the circulatory system that improves the physiological definition of appropriate boundary conditions. Simulations were compared to myocardial strain data obtained from echocardiography, performed on two healthy subjects and two patients diagnosed with chronic IHD. Results show the model ability to simulate jointly the hemodynamic variables (Systolic and diastolic pressures respectively equal to 110 and 60 mmHg) and myocardial strain curves during each phase of the cardiac cycle. A close match is observed between minimum strains obtained from simulations and clinical data from healthy subjects and IHD patient, with a root mean square error around 2 , 81 % and 2 , 63 % respectively. The modifications of regional LV systolic strains observed from IHD patients with respect to healthy cases were partially explained by a decrease of regional cardiac stress. This paper provides a description of a new coupling algorithm between FEM and lumped-parameter models. Results are promising for the analysis of cardiac strains in the context of IHD. • Left ventricle model including electro-mechanical activity and loading conditions. • A coupling algorithm between the finite-element and lumped-parameter models. • Simulation of hemodynamic variables and myocardial strains in ischemic heart disease. [ABSTRACT FROM AUTHOR]

The excess mortality in HCM patients is mainly attributed to the occurrence of SCD. The prediction of ventricular arrhythmias remains challenging and could be improved. This study evaluated the added predictive value of a machine learning-based model combining clinical and conventional imaging parameters with information from left ventricular strain analysis to predict sudden cardiac death (SCD) in patients with hypertrophic cardiomyopathy (HCM). A total of 434 HCM patients (65% men, mean age 56 years) were retrospectively included from two referral centers (Oslo University Hospital, Rennes University Hospital) and followed longitudinally (mean duration 6 years). Mechanical and temporal parameters were automatically extracted from the left ventricle longitudinal strain (LV-LS) segmental curves of each patient and included in a Ridge Regression model alongside conventional clinical and imaging data. The composite endpoint included sustained ventricular tachycardia, appropriate implantable cardioverter defibrillator therapy, aborted cardiac arrest, or sudden cardiac death (Fig. 1). Thirty-four patients (7.8%) met the endpoint with an incidence of ventricular arrhythmias of 0.9%/years. From a subset of 18 most discriminating parameters, including 7 derived from LV-LS, and after n = 200 rounds of cross-validation, the final model showed superior predictive performance compared to conventional models with a mean area under the curve (AUC) of 0.83 ± 0.8. A machine learning model including automatically extracted left ventricular strain-derived parameters was superior in the prediction of sustained ventricular arrhythmias and SCD in patients with HCM compared to existing models. Machine learning model including LV-LS analysis could improve SCD risk stratification in HCM patients (Fig. 1). [ABSTRACT FROM AUTHOR]

The relationship between diastolic dysfunction (DD) and outcome after CRT is debated. The purpose of this study was to evaluate the role of DD in predicting all-cause mortality in heart failure patients undergoing CRT. One-hundred ninety-three patients (age: 67 ± 11 years, QRS width: 167 ± 21 ms, LVEF 28 ± 8%) were included in this multicentre prospective study. Mitral filling pattern, mitral tissue Doppler velocity, tricuspid regurgitation velocity, and indexed left atrial volume were used to classify DD from grade I to III according to the 2016 recommendations of the American Society of Echocardiography/European Association of Cardiovascular Imaging. A reduction of LV end-systolic volume > 15% at 6-month follow-up (FU) identified CRT-responders and was observed in 132 (68%) patients. During a median 35 months FU, 29 (15%) patients died. Through multivariable analysis, coronary artery disease [HR 2.21 (1.00–4.89) P = 0.05], NYHA [HR 2.92 (1.45–5.87), P = 0.003] and grade I DD [HR 0.34 (0.13–0.89)] were shown to be independent predictors of prognosis (Table 1). Grade I DD was associated with a longer survival rate in both responders and non-responders (Fig. 1). Non-responders with grade II-III DD had the worse outcome [HR 12.5 (3.56–44.04), P < 0.0001] Better diastolic function at baseline is associated with improved survival after CRT implantation, independently of CRT-response. [ABSTRACT FROM AUTHOR]

Non-invasive estimation of myocardial work by transthoracic echocardiography is a novel tool to analyse myocardial contraction efficiency during systole. Two methods are described, on using Left ventricular (LV) strain and a LV pressure estimation, and another with only LV strain integrals. The present study analyses their utility in prediction of CRT-response. In total, 243 patients implanted by a CRT according to current recommendations were retrospectively included in hospital university of Rennes. All patients had a complete transthoracic echocardiography at implantation and at 6-moths follow-up. Responders were defined as having a 15% decrease in indexed LV end-systolic volume at follow-up compared to baseline. Baseline characteristics are described in Table 1 ; 25.1% were non-responders. In this group, there were more men, more ischemic cardiomyopathies with more dilated LV. Strain signals were analysed only in the most informative loop, the apical 4 cavities. Myocardial work estimation with LV pressure estimation was previously described. The 3 different integral of strain signal were represented in Fig. 1. According to ROC curves, myocardial work (particularly wasted work in septal wall with AUC = 0.718 ± 0.04) estimated with LV pressure estimation is better than strain integrals to predict LV positive remodelling (best AUC 0.631 ± 0.040) after CRT-implantation. Left ventricular pressure estimation give useful information on top of strain curves for prediction for CRT-response. [ABSTRACT FROM AUTHOR]

Patients undergoing cardiac resynchronisation therapy are heterogeneous. Therefore, the prediction of CRT-response and outcome is challenging. The aim of this study was to evaluate the relative impact of clinical, electrocardiographic, and echocardiographic variables on the left ventricular (LV) remodelling and prognosis of CRT-candidates by the application of machine-learning (ML) approaches. In total, 193 patients undergoing CRT (mean age 67 ± 11 years, QRS width: 167 ± 21 msec) were prospectively included in this multicentre study. We used a combination of the Boruta algorithm and random forest methods (RF) to identify features predicting both CRT-volumetric response and prognosis. The model performance was tested by the area under the receiver-operating curve (AUC). We also applied the K-medoid method to identify clusters of phenotipically-similar patients. From 28 clinical, electrocardiographic, and echocardiographic-derived variables, 16 features were predictive of CRT-response, and 11 features were predictive of prognosis. Among the predictors of CRT-response, 6 variables (38%) pertained to right ventricular (RV) size or function. The tricuspid annular plane systolic excursion was the main feature associated with prognosis. The selected features were associated with a very good prediction of both CRT-response (AUC: 0.81, 95% CI: 0.74–0.87) and outcome (AUC 0.84, 95% CI: 0.75–0.93) (Fig. 1 A–B). An unsupervised ML approach allowed the identifications of two phenogroups of patients who differed significantly in clinical parameters, biventricular size and RV function and had significantly different prognosis (log-rank P < 0.0001; HR: 4.7, 95% CI: 2.1–10.0, P < 0.001) (Table 1). ML can reliably identify clinical and echocardiographic features associated with CRT-response and prognosis. Our results underscore the value of the assessment of RV-size and function parameters for the risk stratification of CRT-candidates. [ABSTRACT FROM AUTHOR]

Abstract: A model of the cardiovascular system (CSV) that consists of the ventricle, the circulatory system and the regulation of the cardiac action is presented. The model of the ventricle includes a description of the electromechanical phenomena occurring during cardiac contraction. It explains the global behaviour of the heart and is coupled with a model of the circulation. The whole cardiovascular system is under the influence of a regulation model. In fact, the cardiovascular system is regulated by the Autonomic Nervous System (ANS). In this work, only the influence of the short-term regulation of blood pressure (the baroreflex) is considered. The model allows the simulation of various physiological tests of the ANS, like the tilt test or the Valsalva manœuvre. These tests are usually used with patients to detect some pathology (syncope for example). But the interpretation of the signals obtained (blood pressure, heart rate) is often difficult because of the complexity of the SCV. It is then possible to improve the comprehension of the interaction between the SCV and the ANS thanks to the model; and to give a physiological interpretation of the signals obtained with the tilt test and the Valsalva manœuvre. [Copyright &y& Elsevier]

Abstract: The model of the cardiovascular system that is presented consists of the ventricle, the circulatory system and the regulation of the cardiac action. The model of the ventricle includes a description of the electromechanical phenomena occurring during cardiac contraction and is coupled with the model of the circulation. The whole cardiovascular system is under the influence of a regulation model. [Copyright &y& Elsevier]

This work aims to evaluate a novel semi-automatic tool for the assessment of volume-strain loops by transthoracic echocardiography (TTE). The proposed method was evaluated on a typical model of left ventricular (LV) diastolic dysfunction: the cardiac amyloidosis. Seventeen patients with proved cardiac amyloidosis and 18 patients with heart failure with preserved ejection fraction (HFpEF) were compared to 19 controls, from a local database. All TTE were performed using Vivid E9 or E95 ultrasound system (General Electrics Healthcare, Horten, Norway). The complete method includes several steps: 1) extraction of LV strain full traces from apical 4 and 2 cavities views, 2) estimation of LV volume from these two traces by spline interpolations, 3) resampling of LV strain curves, determined for the same cardiac beat, (in apical 4-, 2- and 3- cavities views) as a function of pre-defined percentage increments of LV-volume and 4) calculation of the LV volume-strain loop area. (Fig. 1 , panel A) (Table 1): LVEF was similar between all groups whereas global longitudinal strain was significantly lower in amyloidosis group than controls (−14.4 vs. −20.5%; P < 0.001). HFpEF and amyloidosis groups had a worse diastolic function than controls with a greater left atrial volume index (51 vs. 22 mL/m2), a faster tricuspid regurgitation (3.1 and 2.7 vs. 2.0 m/s), a greater E/e' ratio (13.7 and 17.3 vs. 5.9) with a P < 0.001 for all these indices. Simultaneously, the global area of volume-strain loop was significantly lower in HFpEF and amyloidosis group than controls (72 vs. 36 vs. 120.0% mL, respectively, P < 0.0001). HFpEF has an intermediate profile between controls and amyloidosis (Fig. 1 , panel B, HFpEF in green). This area was better correlated with mean e' (r = 0.650, P < 0.001) than all other indices. LV volume-strain loop area appears a very promising new tool to assess semi-automatically diastolic function. [ABSTRACT FROM AUTHOR]

Conflicting data exist about the relationship between cardiac resynchronization therapy (CRT) and diastolic function. Aims of the study are to assess diastolic patterns in patients undergoing CRT according to the 2016 recommendations of the American Society of Echocardiography/European Association of Cardiovascular Imaging and to evaluate the prognostic value of diastolic dysfunction (DD) in CRT candidates. One-hundred ninety-three patients (age: 67 ± 11 years, QRS width: 167 ± 21 ms) were included in this multicentre prospective study. Mitral filling pattern, mitral tissue Doppler velocity, tricuspid regurgitation velocity, and indexed left atrial volume were used to classify DD from grade I to III. CRT-response, defined as a reduction of left ventricular (LV) end-systolic volume > 15% at 6-month follow-up (FU), occurred in 132 (68%) patients. The primary endpoint was a composite of heart transplantation, LV assisted device implantation, or all-cause death during FU and occurred in 29 (15%) patients. CRT was associated with a degradation of DD in non-responders. At multivariable analysis corrected for clinical variables, QRS duration, mitral regurgitation, CRT-response and LV dyssynchrony, grade I DD was associated with a better outcome (HR 0.37, 95% CI: 0.14–0.96). Non-responders with grade II-III DD had the worse prognosis (HR 4.36, 95%CI: 2.10–9.06). The evaluation of DD in CRT candidates allows the prognostic stratification of patients, independently from CRT-response. • Conflicting data exist about the relationship between cardiac resynchronization therapy (CRT) and diastolic function. • CRT was associated with a degradation of diastolic dysfunction in non-responders. Grade I diastolic dysfunction was associated with a better outcome. • Non-responders with grade II or grade III diastiloc dysfunction had the worse prognosis (HR 4.36, 95%CI: 2.10–9.06). • So, the evaluation of diastolic dysfunction in CRT candidates is crucial for best stratification of patients according to their own risk of cardio-vascular event, independently from CRT-response. [ABSTRACT FROM AUTHOR]