We sought to evaluate the capability of the right ventricle to regain normal morphology and function after pulmonary endarterectomy, to correlate right ventricular reverse remodeling with functional status, and to identify independent predictors of clinical failure after surgical intervention.From December 2000 through August 2003, 45 patients underwent isolated pulmonary endarterectomy. Morphology and function of the right ventricle were studied by using a combination of right heart catheterization, cardiac magnetic resonance, and transthoracic echocardiography. Functional status was evaluated by using New York Heart Association class. Full preoperative data were available for 37 candidates. All patients were evaluated before discharge, at 3 months, and at 1, 2, and 3 years postoperatively using the same modalities.Immediately after surgical intervention, right ventricular cavitary dimensions decreased significantly, and tricuspid regurgitation radically improved. Right ventricular ejection fraction and functional status improved and right ventricular hypertrophy reversed over a longer time period. Higher ventricular dimensions and lower ejection fraction of the right ventricle were associated with poorer functional status at any time postoperatively. At discharge, pulmonary vascular resistance of greater than 509 dyne x sec x cm(-5) and right ventricular ejection fraction of 24% or less predicted clinical failure at 12 months' follow-up.After pulmonary endarterectomy, the right ventricle recovers and maintains normal architecture and function over time, regardless of the severity of preoperative disease. Accurate preoperative evaluation of the hemodynamics and anatomy of the thromboembolic lesions are mandatory. If pulmonary endarterectomy is not expected to decrease pulmonary vascular resistance to less than 509 dyne x sec x cm(-5), indication for surgical intervention needs to be carefully evaluated.