Its presence was associated with RV enlargement at rest and an exaggerated increase in right-ventricular-to-right-atrial pressure gradient ( @ @ mm Hg vs @ @ mm Hg , P < @ ) and a blunted increase in fractional area change of the right ventricle ( @ % -LSB- -@ % , @ % -RSB- vs @ % -LSB- @ % , @ % -RSB- , P = @ ) during mild exercise .