Right intraventricular dyssynchrony in idiopathic, heritable, and anorexigen-induced pulmonary arterial hypertension. Cllinical impact and reversibility

Objectives: The 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. Background: Right ventricular dyssynchrony has been described in pulmonary arterial hypertension, but no evidence is available on its prognostic impact and evolution after therapy. Methods: In 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 [6 MWT]), a second assessment was performed after 12 months or when clinical worsening occurred. Results: Patients with right ventricular dyssynchrony (RV-SD4 >18 ms) had advanced WHO class, worse 6 MWT, 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 (r(2) = 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, 6 MWT, 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%). Conclusions: Right ventricular dyssynchrony is frequent in pulmonary arterial hypertension, is an independent predictor of clinical worsening, and might regress during effective treatments.