Evaluation of Right Intraventricular Dyssynchrony by Two-Dimensional Strain Echocardiography in Patients With Pulmonary Arterial Hypertension

Background Right ventricular (RV) function has major prognostic implications for patients with pulmonary arterial hypertension (PAH). Intraventricular dyssynchrony might play an important role in RV dysfunction in these patients. Methods Thirty-six patients with PAH without right bundle branch block (mean age 44 ± 14 yr, 24 women) and 39 controls (mean age 43 ± 18 yr, 26 women) were evaluated. Global and segmental RV longitudinal deformation parameters were recorded by 2-dimensional strain echocardiography from apical 4-chamber views using a 6-segment RV model. The standard deviation of the heart rate–corrected intervals from QRS onset to peak strain for the 6 segments (RV-SD6) was used to quantify right intraventricular dyssynchrony. Results RV-SD6 was significantly higher in patients with PAH compared with controls (63 ± 21 vs 25 ± 15ms, P < .001). Dyssynchrony in patients with PAH was found to derive mainly from delayed contraction of the basal and mid RV free wall. In patients with PAH, RV-SD6 was strongly correlated with RV fractional area change (β = −.519, P = .002), RV myocardial performance index (β = .427, P = .009), and RV global strain (β = .512, P = .002); in models controlling for RV systolic pressure, RV size, and QRS duration, RV-SD6 was still an independent predictor of RV fractional area change (β = −.426, P = .005) and RV global strain (β = .358, P = .031). RV function was significantly worse in the subgroup of patients with PAH (n = 25) with RV-SD6 > 55 ms (the upper 95% limit in controls). Conclusion Right intraventricular dyssynchrony, as quantified by 2-dimensional strain echocardiography, is prevalent in PAH and is associated with more pronounced RV dysfunction. The clinical implications of these findings remain to be determined in follow-up studies. Right ventricular (RV) function has major prognostic implications for patients with pulmonary arterial hypertension (PAH). Intraventricular dyssynchrony might play an important role in RV dysfunction in these patients. Thirty-six patients with PAH without right bundle branch block (mean age 44 ± 14 yr, 24 women) and 39 controls (mean age 43 ± 18 yr, 26 women) were evaluated. Global and segmental RV longitudinal deformation parameters were recorded by 2-dimensional strain echocardiography from apical 4-chamber views using a 6-segment RV model. The standard deviation of the heart rate–corrected intervals from QRS onset to peak strain for the 6 segments (RV-SD6) was used to quantify right intraventricular dyssynchrony. RV-SD6 was significantly higher in patients with PAH compared with controls (63 ± 21 vs 25 ± 15ms, P < .001). Dyssynchrony in patients with PAH was found to derive mainly from delayed contraction of the basal and mid RV free wall. In patients with PAH, RV-SD6 was strongly correlated with RV fractional area change (β = −.519, P = .002), RV myocardial performance index (β = .427, P = .009), and RV global strain (β = .512, P = .002); in models controlling for RV systolic pressure, RV size, and QRS duration, RV-SD6 was still an independent predictor of RV fractional area change (β = −.426, P = .005) and RV global strain (β = .358, P = .031). RV function was significantly worse in the subgroup of patients with PAH (n = 25) with RV-SD6 > 55 ms (the upper 95% limit in controls). Right intraventricular dyssynchrony, as quantified by 2-dimensional strain echocardiography, is prevalent in PAH and is associated with more pronounced RV dysfunction. The clinical implications of these findings remain to be determined in follow-up studies.