Right ventricular dyssynchrony in idiopathic pulmonary arterial hypertension: Determinants and impact on pump function

• Published in: The Journal of heart and lung transplantation Vol. 34; no. 3; pp. 381 - 389
• Main Authors: Badagliacca, Roberto, MD, PhD, Poscia, Roberto, MD, PhD, Pezzuto, Beatrice, MD, Papa, Silvia, MD, Gambardella, Cristina, MD, Francone, Marco, MD, Mezzapesa, Mario, MD, Nocioni, Martina, MD, Nona, Alfred, MD, Rosati, Riccardo, MD, Sciomer, Susanna, MD, Fedele, Francesco, MD, FESC, Dario Vizza, Carmine, MD
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01-03-2015
• Subjects: 2D speckle-tracking echocardiography; Echocardiography; Female; Follow-Up Studies; Humans; Hypertension, Pulmonary - complications; Hypertension, Pulmonary - diagnosis; Hypertension, Pulmonary - physiopathology; Magnetic Resonance Imaging, Cine; Male; Middle Aged; Prognosis; pulmonary arterial hypertension; Pulmonary Wedge Pressure - physiology; Retrospective Studies; right ventricular dyssynchrony; right ventricular function; right ventricular wall stress; Stroke Volume - physiology; Surgery; Vascular Resistance; Ventricular Dysfunction, Right - diagnosis; Ventricular Dysfunction, Right - etiology; Ventricular Dysfunction, Right - physiopathology; Ventricular Function, Right - physiology; Ventricular Remodeling - physiology; 2D speckle-tracking echocardiography; right ventricular wall stress; right ventricular dyssynchrony; pulmonary arterial hypertension; right ventricular function; echocardiography
• ISSN: 1053-2498; 1557-3117
• DOI: 10.1016/j.healun.2014.06.010

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, r2 = 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, r2 = 0.41, p = 0.001), accounting for the significant correlation between RV-SD4 and cardiac index ( r = 0.57, r2 = 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.