Circulation.  133(24):2413-22, 2016 Jun 14.

Tedford,Ryan J. From Divisions of Cardiology (S.H., B.A.H., E.T., A.C.B.,
P.S.R., D.A.K., R.J.T.), Pulmonary and Critical Care (S.C.M., R.L.D.,
T.M.K., P.M.H.), and Rheumatology (L.K.H., A.A.S., Z.M., F.M.W.),
Department of Medicine, Johns Hopkins Medical Institutions, Baltimore, MD;
and Departments of Radiology (C.P.C.-V., S.L.Z.) and Biomedical
Engineering (D.A.K.), Johns Hopkins Medical Institutions, Baltimore, MD.

Abstract
BACKGROUND: Right ventricular (RV) functional reserve affects functional
capacity and prognosis in patients with pulmonary arterial hypertension
(PAH). PAH associated with systemic sclerosis (SSc-PAH) has a
substantially worse prognosis than idiopathic PAH (IPAH), even though many
measures of resting RV function and pulmonary vascular load are similar.
We therefore tested the hypothesis that RV functional reserve is depressed
in SSc-PAH patients.

CONCLUSIONS: RV contractile reserve is depressed in SSc-PAH versus IPAH
subjects, associated with reduced calcium recycling. During exercise, this
results in ventricular-pulmonary vascular uncoupling and acute RV
dilation. RV dilation during exercise can predict adverse
ventricular-vascular coupling in PAH patient