Arnaud Hubert

Atrial function is altered in lone paroxysmal atrial fibrillation in male endurance veteran athletes

Aims Intensive endurance sport practice is associated with an increased risk of atrial fibrillation (AF) in male veteran athletes. Paroxysmal AF (PAF) is the very beginning step of this disease. The description of atrial remodelling occurring at this early stage might enable to depict predictive factors of AF in veteran athletes in order to give them personalized recommendation according to their sport practice. Methods and results Twenty-seven male endurance veteran athletes with documented PAF were retrospectively enrolled and compared with 30 control endurance athletes without documented AF, with similar training level, age, and cardiovascular risk factors. All subjects underwent a resting-electrocardiogram (ECG) to assess the electric remodelling of P-waves as well as an echocardiography, to evaluate the left and right atrial (LA, RA) anatomical and functional (assessed by 2D strain) remodelling. No difference was noted between groups for the ECG P-wave parameters. Atrial function was decreased in the PAF group, particularly the peak atrial longitudinal strain (L-ɛ-Max) of LA (29.3 ± 7.9% vs. 49.1 ± 7.8% respectively in the PAF group and in controls, P < 0.0001) and RA (36.5 ± 7.0% vs. 50.6 ± 10.2%, P < 0.0001). LA and RA volumes were also larger in the PAF group. Receiver operating characteristic analysis demonstrated that L-ɛ-Max of LA [area under curve (AUC): 0.957 ± 0.023] and RA (AUC: 0.901 ± 0.042) had the best ability to identify the athletes with PAF, far better than the anatomical parameters (AUC < 0.75 in all). Conclusion Atrial function analysed by strain in echocardiography is strongly associated with PAF and might enable to identify male endurance veteran athletes at risk to develop AF.

Role of myocardial constructive work in the identification of responders to CRT

Aims Cardiac resynchronization therapy (CRT) plays a pivotal role in the management of patients with heart failure (HF) and wide QRS complex. However, the treatment is plagued by numerous non-responders. Aim of the study is to evaluate the role myocardial work estimated by pressure-strain loops (PSLs) in the comprehension of physiological mechanisms associated with CRT and in the prediction of CRT response. Methods and results Ninety-seven patients with symptomatic HF (ejection fraction: 27 ± 6%, QRS duration 164 ± 18 ms) undergoing CRT implantation according to current recommendations were retrospectively included in the study. Standard 2D and speckle tracking echocardiography were performed before CRT and at the 6-month follow-up (FU). PSL analysis allowed the calculation of global and regional myocardial constructive work (CW) and wasted work (WW). A > 15% reduction in left ventricular (LV) end-systolic volume at FU defined CRT-positive response (CRT-PR). At FU, 63 (65%) patients responded to CRT. Global CW (CWtot) was significantly increased in CRT-responders. At multivariate analysis, CWtot > 1057 mmHg% (OR 14.69, P = 0.005) and septal flash (OR 8.05, P = 0.004) were the only significant predictors of CRT-PR. CWtot was associated with the entity of CRT-induced myocardial remodelling in both ischaemic (r = -0.55, P < 0.0001) and non-ischaemic patients (r = 0.65, P < 0.0001). A CWtot < 1057 mmHg% identified 85% of non-responders with a positive predictive value of 88%. Conclusion Patients with higher CWtot exhibit a favourable response to CRT. These data encourage further studies for the assessment of the myocardial substrate related to the functional response to CRT.

New indices of left ventricular function: let's move from ejection fraction to more physiological parameters

The assessment of myocardial function in the context of valvular heart disease (VHD) remains highly challenging. This article is protected by copyright. All rights reserved

Estimation of myocardial work from pressure–strain loops analysis: an experimental evaluation

Purpose The area of left ventricular (LV) pressure-strain loop (PSL) is used as an index of regional myocardial work. The purpose of the present work is to compare the main segmental PSL markers and the derived global work indices, when they are calculated using an estimated pressure signal or an observed pressure signal. Methods and results In nine patients implanted with a bi-ventricular pace-maker (CRT), LV pressure was invasively measured in five conditions: CRT-off, LV-pacing, right ventricular-pacing and two different CRT-pacing. For each condition, systolic blood pressure was measured by brachial artery cuff-pressure and transthoracic echocardiography loops were recorded simultaneously. The error and relative root mean square error (rRMSE) between measured and estimated pressure were calculated for each patient and each configuration. Correlation coefficient (R2) and Bland-Altman (BA) analysis were performed for PSL area and work indices. A total of 43 different haemodynamic conditions were compared (774 segmental PSL). The global rRMSE between estimated and measured LV-pressure was 12.3 mmHg. The estimated and measured segmental LV-PSL were strongly correlated, with an R2 of 0.98. BA analysis shows that the mean bias for the estimation of segmental LV-PSL area is 86.0 mmHg.%. A significant bias effect with linearly increasing error with pressure values is observed. R2 ≥ 0.88 and a mean bias in BA analysis ≤41.4 mmHg.% was observed for the estimation of global myocardial work indices. Conclusion The non-invasive estimation for LV pressure-strain loop area and the global myocardial work indices obtained from LV-PSL strongly correlates with invasive measurements.

Myocardial infarction and thrombophilia: Do not miss the right diagnosis!

Protein C deficiency is a coagulation cascade disorder often resulting in venous thromboembolic events but is also a possible contributor to arterial thrombosis. To date, approximately ten cases of myocardial infarction (MI) due to protein C deficiency have been reported in the literature. However, affirming this mechanism requires ruling out the most common causes of MI, i.e. the rupture or erosion of an atherosclerotic plaque. Intravascular imaging of coronary arteries can be of help to identify angiographically undetected atherosclerosis. We report a case of an ST-segment elevation myocardial infarction (STEMI) in a young man with apparent evidence of arterial thrombosis resulting from protein C deficiency and heterozygous factor Leiden mutation which was contradicted by intravascular imaging demonstrating atherosclerosis.

Imaging in the field of cardiac resynchronization therapy: a real additive value?

Editorial: Current guidelines on cardiac resynchronization therapy (CRT) justify the use of cardiac imaging only to estimate left ventricular ejection fraction (LV EF)...

Validation of a finite element method framework for cardiac mechanics applications.

Modeling cardiac mechanics is a particularly challenging task, mainly because of the poor understanding of the underlying physiology, the lack of observability and the complexity of the mechanical properties of myocardial tissues. The choice of cardiac mechanic solvers, especially, implies several difficulties, notably due to the potential instability arising from the nonlinearities inherent to the large deformation framework. Furthermore, the verification of the obtained simulations is a difficult task because there is no analytic solutions for these kinds of problems. Hence, the objective of this work is to provide a quantitative verification of a cardiac mechanics implementation based on two published benchmark problems. The first problem consists in deforming a bar whereas the second problem concerns the inflation of a truncated ellipsoid-shaped ventricle, both in the steady state case. Simulations were obtained by using the finite element software GETFEM++. Results were compared to the consensus solution published by 11 groups and the proposed solutions were indistinguishable. The validation of the proposed mechanical model implementation is an important step toward the proposition of a global model of cardiac electro-mechanical activity.

P697New indices for a best quantification of left ventricular function in heart valve diseases

Aims. The Assessment of left ventricular (LV) function remains a clinical challenge especially in patients with preserved LV ejection fraction (EF) and valvular heart diseases (VHD). Mechanical dispersion is supposed to be a strong predictor of events and, to be related to the extent of fibrosis. Regional cardiac work is a new validated and very promising approach to quantify LV-function. We investigated the differences in mechanical dispersions and global LV work (totW) and wasted work fraction (WWF) in normal subjects and in patients with severe primary mitral regurgitation (MR) and severe aortic stenosis (AS). Methods and Results A complete transthoracic echocardiography was performed in 21 normal subject, 97 patients with severe valvulopathy (47 AS, 50 MR) and preserved LV EF. Segmental strain analysis was performed in all patients and the dispersion of regional LV strain curves was computed automatically considering peaks and integrals. The LV-pressure was estimated non-invasively using a standard waveform fitted to valvular events and scaled to systolic blood pressure. Using pressure-strain loops, regional cardiac work indices were computed. LVEF was 66±12 in controls, 65±9 in MR and 65±4% in AS (p=0.125). Global longitudinal strain was -23±2.7 in controls, -24±2.9 in MR and -18±3.2% in AS (p < 0.001). The mechanical dispersion was 38±7.9 in controls, 36±11 in MR, and much higher in the hypertrophied LV of the AS: 60±19ms (p < 0.001). Cardiac work was 2200±260 in controls, 2100±270 in MR, and much lower in AS: 1700±280 mmHg.% (p < 0.001). The wasted work fraction (WWF) was even more describing how different the LV systolic function is in the 3 groups (figure1). Conclusion Longitudinal strain data are robusted and new indices might be calculated based on them. These seem especially promising for a more pathophysiological driven analyzing of LV-functions. Abstract P697 Figure. Abstract P697 Figure.