What mechanism does active fixation in lead positioning involve?

Active fixation in lead positioning specifically involves the use of screw-in technology, which allows for more flexible and secure placement of the lead within the heart tissue. This mechanism provides a reliable method for anchoring the lead by allowing the clinician to screw the lead into the myocardium, which enhances stability and minimizes the risk of displacement over time. The ability to adjust the positioning during the implantation process is a key advantage, as it facilitates precise placement in the desired cardiac chamber, accommodating variations in the anatomy of each patient.

The other choices do not accurately reflect how active fixation works. Adhesive bonding, automatic adaptation to chamber sizes, or reliance solely on manual force do not represent the mechanical advantage and precision offered by screw-in technology, making this option the most appropriate choice to describe the active fixation mechanism in lead positioning.