Left ventricular (LV) atrophic remodelling was described for chronic thromboembolic pulmonary hypertension (PH) but not in other forms of PH. We aimed to assess LV morphometric changes in idiopathic pulmonary arterial hypertension (IPAH) and Eisenmenger's syndrome(ES).

Fifteen patients with IPAH, 15 patients with ES and 15 healthy volunteers were included. Magnetic resonance was used to measure masses of LV, interventricular septum (IVS), LV free wall (LVFW), and LV end diastolic volume (LVEDV) indexed for body surface area.

Between patients with IPAH, ES and controls no differences in LVmass_index (54.4[45.2-63.3] vs 58.7[41.5-106.1] vs 52.8[46.5-59.3], p=0.50), IVSmass_index (21.6[18.2-21.9)] vs 27.4[18.0-32.9] vs 20.7[18.2-23.2], p=0.18), and LVFWmass_index ([32.4[27.1-40.0] vs 36.7[30.9-62.1] vs 32.5[26.9-36.1], p=0.29) were found. LVEDV_index was lower in IPAH patients than in controls and in ES patients (54.9[46.9-58.5] vs 75.2[62.4-88.9] vs 73.5[62.1-77.5], p<0.001). In IPAH LVEDV but not LV mass correlated with pulmonary vascular resistance (r=-0.56, p=0.03) and cardiac output (r=0.59, p=0.02).

LV mass is not reduced in patients with IPAH and with ES and is not affected by haemodynamic severity of PH. LVEDV is reduced in IPAH patients in proportion to reduced pulmonary flow but preserved in patients with ES, where reduced pulmonary flow to LV is compensated by right-to left shunt.