Methods and endocardial screw-in leads for enabling provision of electrical
stimulation to the heart, particularly the His Bundle in the intraventricular septal
wall. An endocardial screw-in lead having a distal end coupled to a retractable
fixation helix wherein a distal portion of the fixation helix extends beyond the
lead distal end when the fixation helix is fully retracted or partially extended
is positioned in proximity to the His Bundle in the septal wall. The lead body
is rotated to attach the distal portion of the fixation helix into the septal wall.
The fixation helix is rotated with respect to the lead body to fully extend the
fixation helix so that a portion of the fixation helix is in proximity to the His
Bundle, enabling provision of electrical stimulation to the His Bundle and/or to
sense electrical signals of the heart traversing the His Bundle through the fixation helix.