A 72 year old man with mechanical valves in both the mitral and aortic positions and a history of one reoperation was referred to our institution for signs of congestive heart failure and suspected valvar dysfunction. The transoesophageal Doppler showed periprosthetic mitral regurgitation that was technically unquantifiable. Under these circumstances the patient was referred to the cardiac catheterisation laboratory for haemodynamic assessment via direct left ventricular puncture. The left ventricular apex was identified with the patient in the modified left lateral decubitus position. Local anaesthetic was infiltrated down to the periosteum of the superior border of the rib at the point of maximal impulse. Then a 21 gauge needle, an introducer, and a stylet were advanced with fluoroscopic guidance toward the right second intercostal space until the left ventricular apex impulse was encountered (panels A, B). Once the left ventricle was entered the needle and stylet were withdrawn, and pressure measurements, dye curves, and ventriculography using a flexible 4 French catheter (panel C) were performed. Mitral regurgitation was found to be severe and periprosthetic in location (panel D). Surgery was subsequently performed with beneficial results.