Ventricular geometry, strain, and rotational mechanics in pulmonary hypertension

Abstract

Background: We tested the hypothesis that right ventricular (RV) pressure overload affects RV function and further influences left ventricular (LV) geometry, which adversely affects LV twist mechanics and segmental function.

Methods and results: Echocardiographic images were prospectively acquired in 44 patients (age, 46+/-12 years; 82% women) with evidence of pulmonary hypertension (estimated pulmonary artery systolic pressure, 71+/-23 mm Hg) and in 44 age- and gender-matched healthy subjects. Patients with intrinsic LV diseases were excluded. RV lateral wall longitudinal strain (LS) and interventricular septal (IVS) LS were reduced in the pulmonary hypertension group compared with control subjects (-15.9+/-7.6% versus -25.5+/-6.1%, P<0.001; and -17.3+/-4.4% versus -20.2+/-3.9%, P=0.002, respectively), whereas LV lateral wall LS was preserved. RV lateral wall LS and IVS LS, but not LV lateral wall LS, correlated with pulmonary artery systolic pressure (r=0.56, P<0.01; r=0.32, P<0.01) and LV eccentricity index (r=0.57, P<0.01; r=0.57, P<0.01). IVS and LV lateral wall circumferential strain (CS) were both reduced in the pulmonary hypertension group. Although IVS CS and LV lateral wall CS correlated with pulmonary artery systolic pressure and LV eccentricity index, after adjustment of CS for LV eccentricity index, differences between groups persisted for IVS CS (P<0.01) but not LV lateral wall CS (P=0.09). LV torsion was decreased in patients with pulmonary hypertension compared with control subjects (9.6+/-4.9 degrees versus 14.7+/-4.9 degrees , P<0.001). LV torsion inversely correlated with pulmonary artery systolic pressure (r=-0.39, P<0.01) and LV eccentricity index (r=-0.3, P<0.01). LV untwisting rates were similar in both groups (P=0.7).

Conclusions: Chronic RV pressure overload directly affects RV longitudinal systolic deformation. RV pressure overload further influences IVS and LV geometry, which impairs LV torsion and segmental LS and CS, more for the IVS than for the free wall of the LV.

Figure 1. Regression Analysis of RV and LV Longitudinal Strain vs. Estimated Pulmonary Systolic Pressures and LV Eccentricity Index

RV LAT LS, right ventricular lateral wall longitudinal strain; IVS LS, interventricular septal longitudinal strain; LV LAT LS, left ventricular lateral wall longitudinal strain; PASP, estimated pulmonary artery systolic pressure; LVED D1/D2, left ventricular end-diastolic eccentricity index. Closed circles, PH patients; open circles, controls.

Figure 2. Regression Analysis of LV Circumferential Strain vs. Estimated Pulmonary Systolic Pressures and LV Eccentricity Index

CS denotes circumferential strain. See abbreviation in Figure 1

Figure 3. Regression Analysis of LV Torsion vs. Estimated Pulmonary Systolic Pressures and LV Eccentricity Index

See abbreviation in Figure 1