LBBAP lead implants
Pacing at the LBB area can result in 3 possible outcomes
•Selective/pure LBBAP capture
•Non selective LBBAP capture (LBBAP and septum both captured)
•LV only septal capture (no LBBAP capture- should move lead)
Appearance and measurements on the 12 lead ECG are used to assist in evaluation of lead positon
•Peak R wave time (PRWT) in V1
•PRWT V5 or left ventricular activation time LVAT
•QRS duration
•No programming differences need to be made for an LBBAP lead
CSP equipment
Implant Process
Located ~1-1.5cm further down the septum from the HIS
Initial septal positioned is confirmed with a “w” pattern occurring in lead V1 when pacing (initial testing is all in unipolar) (some doctors recently stepping away from this methodology)
Lead is rotated perpendicular to the septum (LAO 30-45 degrees)
Paced complex changes from LBBB pattern to RBBB pattern
•Fixations beats (RBBB VPB) often seen during lead fixation
LBB potential may be observed (not always) 20-30ms prior to V
Impedance monitoring- should increase when entering the septum – unipolar imp should be >500 (may go lower with a perforation & loss of injury current)
Pacing at high output and low output occurs to assess whether the lead needs to go further into the septum
•No change in LVAT reflects ideal position
•If abrupt shortening in LVAT, lead depth can be increased
Lead Perforation
No capture in unipolar
Can still have capture in bipolar (anodal only capture)
Loss of injury current
Drop in impedance
Measurements
QRS duration
•the shorter the better
•Ideally <120ms
LVAT/V6 PRWT
•<75ms
•<80ms when left bundle branch block (LBBB)/intraventricular conduction delay/escape rhythm/asystole
•Still possible however to have LBB capture with LVAT 100ms
V1 PRWT
V1 PRWT – V6 PRWT
•Long >60ms selective LBB capture
•Intermediate >33ms non selective LBB capture
•Short <33ms LV septal capture
Programming considerations
Unlike HIS lead implants, there is no need for alternative programming
•Autocapture can remain on
•No change in pulse width duration
AV delay programming may need to be considered
•May need pacing if AV block
•May want to force pace to correct BBB
•May want back up only pacing