title: Right ventricular dyssynchrony in idiopathic pulmonary arterial hypertension: determinants and impact on pump function.
abstract: BACKGROUND
  Right ventricular (RV) dyssynchrony has been described in pulmonary arterial hypertension (PAH), but no evidence is available on its morphologic determinants and its effect on systolic function. The aim of this study was to evaluate the morphologic determinants of RV dyssynchrony by echocardiographic and cardiac magnetic resonance imaging and its effect on systolic function.
  
  
  METHODS
  In 60 consecutive idiopathic PAH (IPAH) patients with narrow QRS, RV dyssynchrony was evaluated by 2D speckle-tracking echocardiography, calculating the standard deviation of the times to peak systolic strain for the four mid-basal RV segments (RV-SD4). Patients were grouped by the median value of RV-SD4 (19 milliseconds) and compared for RV remodeling and systolic function parameters, WHO class, pulmonary hemodynamics and 6-minute walk test (6MWT).
  
  
  RESULTS
  Despite similar pulmonary vascular resistance and mean pulmonary arterial pressure, patients with RV-SD4 at >19 milliseconds had advanced WHO class and worse 6MWT, RV hemodynamics, RV remodeling and systolic function parameters compared with patients at ≤19 milliseconds. The morphologic determinants of RV dyssynchrony resulted RV end-diastolic area, LV diastolic eccentricity index and RV mass volume ratio (r = 0.69, r(2) = 0.47, p < 0.0001). Finally, we found a significant inverse correlation between RV mid-basal segments post-systolic shortening time and cardiac index (r = -0.64, r(2) = 0.41, p = 0.001), accounting for the significant correlation between RV-SD4 and cardiac index (r = 0.57, r(2) = 0.32, p = 0.003).
  
  
  CONCLUSIONS
  In IPAH with narrow QRS, RV dyssynchrony is associated with RV dilation and eccentric hypertrophy pattern, suggesting a role of segmental wall stress heterogeneity as the major determinant of mechanical delay. Post-systolic shortening, as inefficient contraction, contributes to pump dysfunction.
authors.affiliation: Departments of a?>Cardiovascular and Respiratory Science. Electronic address: roberto.badagliacca@uniroma1.it.
authors.forename: Roberto
authors.initials: R
authors.lastname: Badagliacca
authors.affiliation: Departments of a?>Cardiovascular and Respiratory Science.
authors.forename: Roberto
authors.initials: R
authors.lastname: Poscia
authors.affiliation: Departments of a?>Cardiovascular and Respiratory Science.
authors.forename: Beatrice
authors.initials: B
authors.lastname: Pezzuto
authors.affiliation: Departments of a?>Cardiovascular and Respiratory Science.
authors.forename: Silvia
authors.initials: S
authors.lastname: Papa
authors.affiliation: Departments of a?>Cardiovascular and Respiratory Science.
authors.forename: Cristina
authors.initials: C
authors.lastname: Gambardella
authors.affiliation: Radiological Science, Sapienza University of Rome, Rome, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Francone
authors.affiliation: Departments of a?>Cardiovascular and Respiratory Science.
authors.forename: Mario
authors.initials: M
authors.lastname: Mezzapesa
authors.affiliation: Departments of a?>Cardiovascular and Respiratory Science.
authors.forename: Martina
authors.initials: M
authors.lastname: Nocioni
authors.affiliation: Departments of a?>Cardiovascular and Respiratory Science.
authors.forename: Alfred
authors.initials: A
authors.lastname: Nona
authors.affiliation: Radiological Science, Sapienza University of Rome, Rome, Italy.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Rosati
authors.affiliation: Departments of a?>Cardiovascular and Respiratory Science.
authors.forename: Susanna
authors.initials: S
authors.lastname: Sciomer
authors.affiliation: Departments of a?>Cardiovascular and Respiratory Science.
authors.forename: Francesco
authors.initials: F
authors.lastname: Fedele
authors.affiliation: Departments of a?>Cardiovascular and Respiratory Science.
authors.forename: Carmine
authors.initials: C
authors.lastname: Dario Vizza
mesh_terms: D004452:Echocardiography; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006976:Hypertension, Pulmonary / Q000150:complications* / Q000175:diagnosis / Q000503:physiopathology; D019028:Magnetic Resonance Imaging, Cine; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011669:Pulmonary Wedge Pressure / Q000502:physiology*; D012189:Retrospective Studies; D013318:Stroke Volume / Q000502:physiology*; D014655:Vascular Resistance; D018497:Ventricular Dysfunction, Right / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology; D016278:Ventricular Function, Right / Q000502:physiology*; D020257:Ventricular Remodeling / Q000502:physiology*
keywords: 2D speckle-tracking echocardiography; echocardiography; pulmonary arterial hypertension; right ventricular dyssynchrony; right ventricular function; right ventricular wall stress