Discussion
The MTPS is an expanding technology with various advantages over TTPS.
Conventional pacemaker therapy requires transvenous leads, commonly
implanted via the upper central veins. In patients with occlusion of
this transvenous axis epicardial permanent pacing has traditionally been
the only viable alternative, even if encumbered by the risks of surgical
approach, especially for frail patients, and increasing pacing
thresholds over the time1. LP, since requiring only
femoral vein access, represents a modern approach to permanent pacing in
case of upper central venous obstruction involving the traditional
venous access route for pacing leads3,4.
However, clinical condition underlying complete obstruction of great
venous vessels may be the most disparate and severe highlighting the
possibility of unpredictable and challenging intraoperative conditions
that are difficult to manage. An adequate preoperative imaging and a
scrupulous study of the case may be very helpful to provide all the
informations required for safe management of the procedure. In our case,
multidetector computed tomographic and three-dimensional reconstruction
provided a detailed image of the right atrium, allowing a precise
evaluation of the extension of the cancer mass and the thrombotic
expansion from the roof inside the right atrium. This information was
essential to establish in advance the probability of a successful
manoeuvrablity of the delivery catheter inside the atrial chamber
without mobilizing thrombotic or neoplastic emboli.
In addition, we injected a small amount of contrast media through a
pigtail catheter previously advanced over the wire up to the right
atrium to obtain a real time imaging of the residual atrial chamber
before advancing the large steerable MTPS delivery system.
This case describes a quite rare condition in which a LP is the only
reasonable option to treat an atrioventricular block, although the
patient was in sinus rhythm and the MTPS was a single chamber pacing
system. LP therapy is a groundbreaking field in rapid development. With
the recent introduction of AV Micra technology, with an
accelerometer-based atrial sensing allowing a good atrioventricular
synchrony, expanding indications are expected5,6.
Appliability of LP technology is a field in continuous evolution and the
operator might face complex and unexplored procedural situation.
Awareness of potentiality and operative limits of this technology is
still growing.