RESUMO
The pulmonary circulation after one and one-half ventricle repair is complex because of the direct connection of two sources of blood flow. Associated pulmonary regurgitation further complicates the pulmonary circulation. We report the complex hemodynamics depicted by phase-contrast magnetic resonance imaging in a patient with one and one-half ventricle circuit and severe pulmonary regurgitation. Antegrade superior vena caval flow occurred almost exclusively during diastole and regurgitated into the right ventricle. Consequently, the entire systemic venous return reached the right ventricle during diastole and is pumped back into the pulmonary arteries in systole. The case highlights the importance of analyzing flow patterns phase-by phase throughout the cardiac cycle instead of relying on the net flow volumes through each source of pulmonary blood flow.