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.