Resistance may be increased by a severe, long-standing lung disorder, such as emphysema or pulmonary hypertension, by disorders involving the left side
of the heart, or rarely by narrowing
of the
pulmonary valve (pulmonic stenosis). To compensate, the right ventricle enlarges, stretching the tricuspid valve and causing regurgitation....You have some right ventricle enlargement, no narrowing of the tricuspid valve that would enlarge the right ventricle.