Closing the cardioplegia cannulation site can be challenging in minimally invasive video-assisted cardiac surgery. The Cor-Knot system is used to tie down valve sutures within the heart efficiently, although erosions to neighboring structures are reported. We hypothesized that a modification of the Cor-Knot system could enable safe hemostasis of the cardioplegia aortic root site and avoid erosions of the aorta or right atrium. This is a single-arm prospective study including 20 consecutive patients operated through a video-assisted method at our clinic between January 2019 and February 2019. At the end of the procedure, the suture was passed through a Cor-Knot device and crimped on a band of Teflon-felt. The two tips of the Teflon-felt toward the right atrium were put together and tightened with a 5/0 Prolene suture in order to protect the sharp ends of the device. Hemostasis was achieved using the technique in all 20 patients, with no requirement for further suture placement to ensure hemostasis of the cardioplegia cannulation site. The device was protected from the right atrial appendage and there was no bleeding. At 6-month follow-up, no patients required a reoperation for aortic or right atrial erosion. The Cor-Knot system was used off-label to close the cardioplegia cannulation site in minimally invasive surgery. This appears safe and effective in our initial 20-patient experience.