Personne :
Tizón-Marcos, Helena

En cours de chargement...
Photo de profil
Adresse électronique
Date de naissance
Projets de recherche
Structures organisationnelles
Nom de famille
Institut universitaire de cardiologie et de pneumologie de Québec, Université Laval
Identifiant Canadiana

Résultats de recherche

Voici les éléments 1 - 6 sur 6
  • Publication
    Accès libre
    Trabeculated myocardium in healthy adults : a first step in understanding the diagnosis of non-compaction cardiomyopathy by magnetic resonance
    (2012) Tizón-Marcos, Helena; Larose, Éric
    La cardiomyopathie non-compacté (NCC) est une maladie rare avec des critères diagnostiques basés sur la détection de l’augmentation du myocarde trabeculé par échocardiographie. L’imagerie par résonance magnétique (IRM) est devenue la méthode de référence pour étudier la fonction et la morphologie du cœur compte tenu de sa meilleure résolution spatiale et temporale. Toutefois, les critères diagnostiques de NCC que nous utilisons en ce moment en IRM ont été tirés d’études en échocardiographie. Ceci pourrait impliquer une augmentation de l’incidence de nouveaux cas de NCC, de même que la positivité chez les adultes en santé. Le présent travail a voulu étudier la “normalité” par IRM en termes de présence et de distribution de myocarde trabeculé chez les adultes en santé et déterminer la présence des associations entre le myocarde trabeculé et les paramètres de fonction cardiaque.
  • Publication
    Accès libre
    Prevalence of left ventricle non-compaction criteria in adult patients with bicuspid aortic valve versus healthy control subjects
    (BMJ Publishing Group, 2018-10-07) Guzzetti, Ezequiel; Tizón-Marcos, Helena; Larose, Éric; Shen, Mylène; Le Ven, Florent; Chetaille, Philippe; Bédard, Élisabeth; Capoulade, Romain; Pibarot, Philippe; Clavel, Marie-Annick; Tastet, Lionel; Salaun, Erwan; Arsenault, Marie
    Objective The aim of this study was to compare the prevalence of left ventricle non-compaction (LVNC) criteria (or hypertrabeculation) in a cohort of patients with bicuspid aortic valve (BAV) and healthy control subjects (CTL) without cardiovascular disease using cardiovascular MR (CMR). Methods 79 patients with BAV and 85 CTL with tricuspid aortic valve and free of known cardiovascular disease underwent CMR to evaluate the presence of LVNC criteria. The left ventricle was assessed at end-systole and end-diastole, in the short-axis, two-chamber and four-chamber views and divided into the 16 standardised myocardial segments. LVNC was assessed using the non-compacted/compacted (NC/C) myocardium ratio and was considered to be present if at least one of the myocardial segments had a NC/C ratio superior to the cut-off values defined in previous studies: Jenni et al (>2.0 end-systole); Petersen et al (>2.3 end-diastole); or Fazio et al (>2.5 end-diastole). Results 15 CTL (17.6%) vs 8 BAV (10.1%) fulfilled Jenni et al’s criterion; 69 CTL (81.2%) vs 49 BAV (62.0%) fulfilled Petersen et al’s criterion; and 66 CTL (77.6%) vs 43 BAV (54.4%) fulfilled Fazio et al’s criterion. Petersen et al and Fazio et al’s LVNC criteria were met more often by CTL (p=0.006 and p=0.002, respectively) than patients with BAV, whereas this difference was not statistically significant according to Jenni et al’s criterion (p=0.17). In multivariable analyses, after adjusting for age, sex, the presence of significant valve dysfunction (>mild stenosis or >mild regurgitation), indexed LV mass, indexed LV end-diastolic volume and LV ejection fraction, BAV was not associated with any of the three LVNC criteria. Conclusion Patients with BAV do not harbour more LVNC than the general population and there is no evidence that they are at higher risk for the development of LVNC cardiomyopathy.
  • Publication
    Cardiac morphology and function reference values derived from a large subset of healthy young Caucasian adults by magnetic resonance imaging
    (European Association of Echocardiography, 2015-09-09) De Larochellière, Élianne; Tizón-Marcos, Helena; Larose, Éric; Bibeau, Karine; Le Ven, Florent; Pibarot, Philippe; Deschepper, Christian F.; Bissonnette, Stéphanie.
    Aims: Assessment of cardiac anatomy and function by cardiovascular magnetic resonance (CMR) is accurate and reproducible and is commonly performed to clarify borderline results obtained by other techniques. Normal reference values are lacking in a large sample of young healthy adults. As CMR is increasingly solicited to discriminate normality from equivocal disease in this population, we sought to determine reliable reference values. Methods and results: A sample of 434 Caucasian adults aged 26 ± 4 years (45% male) without cardiovascular disease or risk factors (including obesity and smoking) underwent CMR. Blood pressure, electrocardiogram, and plasma markers (lipid profile, fasting glucose, troponin, and Nt-pro-BNP) were within normal limits and typical of a low-cardiometabolic-risk profile. End-diastolic (ED), end-systolic (ES), and stroke volumes were greater in men for left and right atria and ventricles. Left ventricular (LV) mass was higher in men. ED wall thickness of all segments was greater in men, whereas ES wall thickening (segmental function) was similar in both genders. After normalization to body surface area, all gender differences remained. Left and right ventricular volumes were lower, and left atrial volumes were higher in older individuals. In contrast, LV mass was not associated with age. Conclusion: This is the first large database of reference ranges for ventricular and atrial functions, volumes, and mass in young Caucasian men and women devoid of cardiovascular disease and risk factors. These data will contribute to improving the accuracy of CMR interpretation for clinical and research applications.
  • Publication
    Valve tissue characterization by magnetic resonance imaging in calcific aortic valve disease
    (Canadian Cardiology Publications., 2014-10-07) Tizón-Marcos, Helena; Larose, Éric; Le Ven, Florent; Fuchs, Christina; Pibarot, Philippe; Mathieu, Patrick
    Background: Calcific aortic valve disease affects 10%-15% of the elderly population, causing considerable morbidity and mortality. There is no imaging technique that allows for the assessment of tissue composition of the valve in vivo. We thus investigated whether multiparametric magnetic resonance imaging (MRI) could characterize and quantify lipid, fibrous, and mineralized tissues within aortic valve (AV) cusps. Methods: AV leaflets were explanted from patients with severe aortic stenosis at the time of valve replacement surgery. Aortic cusps were imaged ex vivo using 1.5 T MRI using 3 gradient-echo sequences with T1, moderate T2, and proton density weightings (T1w, T2w, and PDw). Histopathologic analysis was performed on coregistered slices to identify and measure mineralized tissue, fibrous tissue, and lipid-rich tissue. Area and mean grey values were measured in all 3 weightings by standardized software. Results: Four hundred ninety-two regions of interest from 30 AV leaflets were studied. Total leaflet surface and the areas of mineralized (P < 0.0001), fibrous (P = 0.002), and lipid-rich (P = 0.0001) tissues measured by MRI matched closely those measured by histopathologic examination. All 3 weightings provided significant discrimination between median grey values for mineralized, fibrous, and lipid-rich tissues (P < 0.0001 for T1w, moderate T2w, and PDw). A best-fit equation integrating the grey value data from all 3 weightings allowed multiparametric MRI to identify valve leaflet components with areas under the receiver operating characteristic curve of 0.92, 0.81, and 0.72, respectively. Conclusions: AV leaflet characteristics, including tissue composition, distribution, and area, may be successfully measured by multiparametric MRI with good to excellent accuracy.
  • Publication
    Characteristics of trabeculated myocardium burden in young and apparently healthy adults
    (American College of Cardiology, 2014-07-18) Bertrand, Olivier; Paz Ricapito, Maria de la; Tizón-Marcos, Helena; Larose, Éric; Bibeau, Karine; Le Ven, Florent; Bédard, Élisabeth; Sinha, Swapnil; Pasian, Sergio; Engert, James; Pibarot, Philippe; Deschepper, Christian
    Increased myocardial trabeculations define noncompaction cardiomyopathy (NCC). Imaging advancements have led to increasingly common identification of prominent trabeculations with unknown implications. We quantified and determined the impact of trabeculations' burden on cardiac function and stretch in a population of healthy young adults. One hundred adults aged 18 to 35 years (28 ± 4 years, 55% women) without known cardiovascular disease were prospectively studied by cardiovascular magnetic resonance. Left ventricular (LV) volumes, segmental function, and ejection fraction (EF) and left atrial volumes were determined. Thickness and area of trabeculated (T) and dense (D) myocardium were measured for each standardized LV segment. N-terminal pro-brain natriuretic peptide (Nt-pro-BNP) was measured. Eighteen percent of the subjects had ≥1 positive traditional criteria for NCC, and 11% meet new proposed NCC cardiovascular magnetic resonance criteria. Trabeculated over dense myocardium ratio (T/D) ratios were uniformly greater at end-diastole versus end-systole (0.90 ± 0.25 vs 0.42 ± 0.13, p <0.0001), in women versus men (0.85 ± 0.24 vs 0.72 ± 0.19, p = 0.006), at anterior versus nonanterior segments (1.41 ± 0.59 vs 0.88 ± 0.35, p <0.0001), and at apical versus nonapical segments (1.31 ± 0.56 vs 0.87 ± 0.38, p <0.0001). The largest T/D ratios were associated with lower LVEF (57.0 ± 5.3 vs 62 ± 5.5, p = 0.0001) and greater Nt-pro-BNP (203 ± 98 vs 155 ± 103, p = 0.04). Multivariable regression identified greater end-systolic T/D ratios as the strongest independent predictor of lower LVEF, beyond age and gender, left atrial or LV volumes, and Nt-pro-BNP (β = −9.9, 95% CI −15 to 4.9, p <0.001). In conclusion, healthy adults possess variable amounts of trabeculations that regularly meet criteria for NCC. Greater trabeculations are associated with decreased LV function. Apparently healthy young adults with increased trabecular burden possess evidence of mildly impaired cardiac function.
  • Publication
    Transient myocardial tissue and function changes during a marathon in less fit marathon runners
    (Elsevier, 2013-10-01) Bertrand, Olivier; Gaudreault, Valérie; Tizón-Marcos, Helena; Larose, Éric; Rodés-Cabau, Josep; Gilbert, Philippe; Amyot, Marc; Poirier, Paul; Pibarot, Philippe; Després, Jean-Pierre
    Background : Although regular physical activity improves health, strenuous exercise might transiently increase cardiac risk. Training and fitness might provide protection. Methods : We prospectively studied 20 recreational marathon runners without known cardiovascular disease or symptoms: at peak training before, immediately after, and 3 months after a 42.2-km marathon. Changes in global/segmental myocardial function, edema, resting perfusion, and fibrosis were measured. Results : At peak training, runners exercised 8.1 ± 2.3 hours and 62 ± 18 km per week with mean maximal oxygen consumption (VO2max) of 53.2 ± 8.3 mL/kg/min. In response to the marathon, global left ventricular and right ventricular ejection fraction decreased in half of the runners; these runners had poorer peak training distance, training time, and fitness level. Change in global left ventricular ejection fraction was associated with VO2max. Overall, 36% of segments developed edema, 53% decreased function, and 59% decreased perfusion. Significant agreement was observed between segment decreasing function, decreasing perfusion, and developing edema. Myocardial changes were reversible at 3 months. Conclusions : Completing a marathon leads to localized myocardial edema, diminished perfusion, and decreased function occurring more extensively in less trained and fit runners. Although reversible, these changes might contribute to the transient increase in cardiac risk reported during sustained vigorous exercise.