title: Left atrial mechanics strongly predict functional capacity assessed by cardiopulmonary exercise testing in subjects without structural heart disease.
abstract: Left atrium function is essential for cardiovascular performance and is evaluable by two-dimensional speckle-tracking echocardiography (2D-STE). Our aim was to determine how echocardiographic parameters interrelate with exercise capacity and ventilatory efficiency in subjects with no structural heart disease. Asymptomatic volunteers, in sinus rhythm and with normal biventricular size and function, were recruited from a community-based population. Individuals with moderate-to-severe valvular disease, pulmonary hypertension, and history of cardiac disease were excluded. We performed a transthoracic echocardiogram and assessed left atrial (LA) and left ventricular (LV) mechanics via 2D-STE. Cardiopulmonary exercise testing by treadmill took place immediately thereafter. Peak oxygen uptake (VO2) served as measure of functional capacity and ventilation/carbon dioxide output (VE/VCO2) slope as surrogate of ventilation/perfusion mismatch. 20 subjects were included (age 51 ± 14 years, male gender 65%). Peak VO2strongly correlated with age (r = -0.83; P < 0.01), with E/e' ratio (r = -0.72; P < 0.01), and with LA reservoir- and conduit-phase mechanics, particularly with LA conduit strain rate (SR) (r = -0.82; P < 0.01), but showed no correlation with LA volume index or LV mechanics. A similar pattern of associations was identified for VE/VCO2slope. In multivariate analysis, LA conduit SR (β = -0.69; P = 0.02) emerged as sole independent correlate of peak VO2, adjusted for age and for E/e' ratio (adjusted r2= 0.76; P < 0.01). Conduit and reservoir components of LA mechanics displayed strong associations with peak VO2and VE/VCO2slope. LA conduit-phase SR seems best suited as echocardiographic marker of functional capacity in subjects with no structural heart disease.
authors.affiliation: Cardiology Department, Centro Hospitalar e Universitário de Coimbra, Praceta Prof. Mota Pinto, 3000-075, Coimbra, Portugal. luispcleite@gmail.com.|Faculty of Medicine of the University of Coimbra, Coimbra, Portugal. luispcleite@gmail.com.
authors.forename: Luís
authors.identifier: http://orcid.org/0000-0002-8493-6935
authors.initials: L
authors.lastname: Leite
authors.affiliation: Cardiology Department, Centro Hospitalar e Universitário de Coimbra, Praceta Prof. Mota Pinto, 3000-075, Coimbra, Portugal.
authors.forename: Sofia Lázaro
authors.initials: SL
authors.lastname: Mendes
authors.affiliation: Cardiology Department, Centro Hospitalar e Universitário de Coimbra, Praceta Prof. Mota Pinto, 3000-075, Coimbra, Portugal.|Faculty of Medicine of the University of Coimbra, Coimbra, Portugal.
authors.forename: Rui
authors.initials: R
authors.lastname: Baptista
authors.affiliation: Cardiology Department, Centro Hospitalar e Universitário de Coimbra, Praceta Prof. Mota Pinto, 3000-075, Coimbra, Portugal.|Faculty of Medicine of the University of Coimbra, Coimbra, Portugal.
authors.forename: Rogério
authors.initials: R
authors.lastname: Teixeira
authors.affiliation: Cardiology Department, Centro Hospitalar e Universitário de Coimbra, Praceta Prof. Mota Pinto, 3000-075, Coimbra, Portugal.|Faculty of Medicine of the University of Coimbra, Coimbra, Portugal.
authors.forename: Manuel
authors.initials: M
authors.lastname: Oliveira-Santos
authors.affiliation: Cardiology Department, Centro Hospitalar e Universitário de Coimbra, Praceta Prof. Mota Pinto, 3000-075, Coimbra, Portugal.
authors.forename: Nelson
authors.initials: N
authors.lastname: Ribeiro
authors.affiliation: Cardiology Department, Centro Hospitalar e Universitário de Coimbra, Praceta Prof. Mota Pinto, 3000-075, Coimbra, Portugal.
authors.forename: Rosa
authors.initials: R
authors.lastname: Coutinho
authors.affiliation: Cardiology Department, Centro Hospitalar e Universitário de Coimbra, Praceta Prof. Mota Pinto, 3000-075, Coimbra, Portugal.
authors.forename: Victor
authors.initials: V
authors.lastname: Monteiro
authors.affiliation: Cardiology Department, Centro Hospitalar e Universitário de Coimbra, Praceta Prof. Mota Pinto, 3000-075, Coimbra, Portugal.
authors.forename: Rui
authors.initials: R
authors.lastname: Martins
authors.affiliation: Cardiology Department, Centro Hospitalar e Universitário de Coimbra, Praceta Prof. Mota Pinto, 3000-075, Coimbra, Portugal.
authors.forename: Graça
authors.initials: G
authors.lastname: Castro
authors.affiliation: Cardiology Department, Centro Hospitalar e Universitário de Coimbra, Praceta Prof. Mota Pinto, 3000-075, Coimbra, Portugal.|Faculty of Medicine of the University of Coimbra, Coimbra, Portugal.
authors.forename: Maria João
authors.initials: MJ
authors.lastname: Ferreira
authors.affiliation: Cardiology Department, Centro Hospitalar e Universitário de Coimbra, Praceta Prof. Mota Pinto, 3000-075, Coimbra, Portugal.
authors.forename: Mariano
authors.initials: M
authors.lastname: Pego
mesh_terms: D000328:Adult; D000368:Aged; D058070:Asymptomatic Diseases; D016279:Atrial Function, Left; D001696:Biomechanical Phenomena; D000072599:Cardiorespiratory Fitness; D002318:Cardiovascular Diseases / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology; D003430:Cross-Sectional Studies; D004452:Echocardiography; D005080:Exercise Test; D005260:Female; D006304:Health Status; D006325:Heart Atria / Q000000981:diagnostic imaging / Q000503:physiopathology; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D015588:Observer Variation; D010101:Oxygen Consumption; D011237:Predictive Value of Tests; D012123:Pulmonary Ventilation; D015203:Reproducibility of Results; D012307:Risk Factors; D016277:Ventricular Function, Left
keywords: Cardiopulmonary exercise testing; Functional capacity; Left atrium; Speckle-tracking echocardiography