Right Intraventricular Dyssynchrony in Idiopathic, Heritable, and Anorexigen-Induced Pulmonary Arterial Hypertension: Clinical Impact and Reversibility

Abstract

ObjectivesThe aim of this study was to determine the prevalence of right intraventricular dyssynchrony, its determinants and prognostic impact in idiopathic, heritable, and anorexigen-induced pulmonary arterial hypertension. BackgroundRight ventricular dyssynchrony has been described in pulmonary arterial hypertension, but no evidence is available on its prognostic impact and evolution after therapy. MethodsIn 83 consecutive therapy-naïve patients, right ventricular dyssynchrony was evaluated by 2-dimensional speckle-tracking echocardiography calculating the standard deviation of the times to peak-systolic strain for the 4 mid-basal right ventricular segments (RV-SD4). After baseline (World Health Organization [WHO] class, pulmonary hemodynamics, 6-min walk test [6MWT]), a second assessment was performed after 12 months or when clinical worsening occurred. ResultsPatients with right ventricular dyssynchrony (RV-SD4 >18 ms) had advanced WHO class, worse 6MWT, right ventricular remodeling, and hemodynamic profile compared with patients ≤18 ms. Determinants of dyssynchrony included pulmonary vascular resistance, QRS duration, and right ventricular end-diastolic area (r2 = 0.38; p < 0.000001). At 12 months, 32.5% of patients presented clinical worsening (actuarial rates: 19% at 6 months, 31% at 1 year). Multivariable models for clinical worsening prediction showed that the addition of RV-SD4 to clinical and hemodynamic variables (WHO IV, 6MWT, and cardiac index) significantly increased the prognostic power of the model (0.74 vs. 0.81; p = 0.005, 95% confidence interval [CI]: 0.02 to 0.11). Receiver operating characteristic analysis identified RV-SD4 ≥ 23 ms as the best cutoff value for clinical worsening prediction (95% negative predictive value). At 12 months, normalization of dyssynchrony was achieved in patients with a large reduction of pulmonary vascular resistance (–42 ± 4%). ConclusionsRight ventricular dyssynchrony is frequent in pulmonary arterial hypertension, is an independent predictor of clinical worsening, and might regress during effective treatments.