Attempted pulmonary artery catheterization via the left internal jugular vein resulted in a misdiagnosis of pulmonary hypertension before transesophageal echocardiography revealed the catheter positioned in the ascending aorta. Inadvertent aortic cannulation through an unusual type of partial anomalous pulmonary venous connection was confirmed with transcatheter fluoroscopy and later at autopsy. Partial anomalous pulmonary venous connection describes one or more of the pulmonary veins draining into the right atrium or its tributaries instead of the left atrium.