Physiology of isolated anomalous pulmonary venous connection of a single pulmonary vein as determined by cardiac magnetic resonance imaging.

The physiology of isolated partially anomalous pulmonary venous connection of a single pulmonary vein has yet to be fully characterized. This study assessed the magnitude of the left-to-right shunt and right ventricular (RV) dilation from a single anomalous pulmonary vein using cardiac magnetic resonance imaging. Subjects with >1 anomalous pulmonary vein or associated lesions, including atrial septal defects, were excluded. In the 6 subjects identified, the median pulmonary-to-systemic flow ratio was 1.55 (range 1.3 to 1.6). The mean RV end-diastolic volume indexed to body surface area in the subjects was significantly larger than in a normal reference cohort (108 +/- 16 vs 78 +/- 18 cm(3)/m(2), p = 0.0009) and greater than the upper limit of normal in all 6 subjects. Older age did not correlate with increased magnitude of shunting (r = 0.3, p = 0.5), but increased age did correlate with RV end-diastolic volume indexed to body surface area (r = 0.96, p = 0.01). Isolated partially anomalous pulmonary venous connection with only 1 vein connecting anomalously results in a modest left-to-right shunt and mild RV dilation.