Left cardiac support postcardiotomy requires a second operation for removal of the atrial cannula following weaning from assistance. To avoid the risk of this procedure, we used a transseptal cannula prototype. The cannula was introduced percutaneously through the femoral vein and advanced into the left atrium guided by the finger of the surgeon. Optimal positioning of the tip of the cannula was verified by perioperative transesophageal echocardiography. A long arterial cannula was positioned in the descending aorta via the femoral artery and a Carmeda circuit with a centrifugal pump was connected to both cannulas. This procedure was used in 3 patients with low cardiac output who underwent emergency surgery, a 63‐year‐old patient referred for aortic and mitral valve replacement, a 54‐year‐old man for aortic valve replacement, and a 64‐year‐old patient in the acute phase of myocardial infarction after myocardial revascularization. The assistance was used systematically at the end of the operation. The assist flow was 1.2–2.6 L/min. The patients were all weaned from support between 18 h and 8 days later. No complications related to the device occurred. Both cannulas were removed surgically from the femoral vessels without reopening the chest. This new procedure is of interest for 2 reasons: the systematic implantation allows for early assistance, and the use of a percutaneous approach avoids the risk of reopening the chest. More cases are needed to confirm this initial good impression.