Rationale for lumenless leads
Lumenless leads were first developed over 20 years ago with an aim to
reduce the diameter of pacing leads and allow precise catheter delivery
while improving reliability[1]. Smaller diameter leads reduce
subclavian crush, venous and valvular stenosis, and improve the ease of
extraction[1-3] . Currently, the model 3830 lead (Medtronic, Inc.,
Minneapolis, MN) is the only available lumenless pacing lead. This lead
has demonstrated excellent acute and long- term electrical
performance[4, 5]. Figure one depicts the difference between the
design of this lead and others. This lead utilizes a flexible inner
cable as the core conductor coupled to a fixed, electrically active
helix. The flexible central cable is intended to reduce the risk of
fracture, while also providing a stable platform for lead extraction.
There is now a similarly designed defibrillation lead in clinical
trial[6].
These leads were initially used for standard endocardial pacing but are
now commonly used for selective conduction system pacing. The
steerability of the delivery system allows for ease of site selection,
while the small diameter of the lead allows for ease of tissue
penetration. Interest in directly pacing the conduction system began in
1978[7]. Modern conduction system pacing first targeted the bundle
of His and now more commonly targets the matrix of the left bundle by
attempting to penetrate into the interventricular septum[8, 9].