Discussion
Participants were asked to simulate standard electrophysiology catheter movements by completing a short task in a challenging anatomical space produced by a pediatric size simulator. The study population included participants experienced with manipulating catheters as well as participants who do not regularly manipulate catheters. The addition of a novel torque tool resulted in reduced muscle activation with repeated movements and a subjective decrease in the task workload, including for participants who regularly manipulate catheters. There was no noticeable difference in measurable success as defined by time to complete the task with the use of the torque tool compared to the bare catheters. Likewise, participants were equally successful in their attempts to create a simulated 60-s ablation lesion. This held true for participants experienced with manipulating catheters. This suggests that the novel torque tool may be easier to use and preferred over bare catheters and does not add significant procedural time.
Based on self-reported scoring of the task workload, participants did not report a change in mental or temporal demand, indicating that the tool is not overly complex or difficult to use. Furthermore, reported reduction in physical demand, effort, and frustration and improvement in performance suggest that the torque tool improves the workload of electrophysiology and ablation procedures, even among participants highly experienced with manipulating catheters.
The left abductor pollicis was the primary muscle of interest given its heavy involvement in the pinching mechanics involved in torquing and manipulating catheters. The significant reduction in activation of this specific muscle suggests that the torque tool reduces not only the maximum activation required to grip and torque the catheter but also the overall work of the muscle when pinching and torquing catheters. This is further demonstrated by the significant reduction in the average activation of some of the other muscles recruited for pinching and torquing maneuvers. It should be noted that only one 60-s lesion was simulated in the study, while standard electrophysiology procedures often involve the creation of multiple lesions, culminating in the physician applying torquing and then isometrically holding the position many times throughout the procedure. This repeated muscle activity with limited rest between lesions may result in a rapid buildup of muscle fatigue [
10]. As such, the significant reduction in muscle activation provided by the catheter torque tool may prove to be even greater in a real case compared to this simulation.
Physicians not experienced with manipulating catheters are likely less skilled at maneuvering the catheters with smooth and relaxed movements. The reduction in muscle activation across all muscle groups evaluated was more prevalent when these participants were included in the analysis than when muscle usage was evaluated for participants experienced with manipulating catheters only. This may suggest the tool is more beneficial for physicians new to the specialty; however, the significant reduction in mean muscle activation for the abductor pollicis and brachioradialis seen in participants experienced with manipulating catheters suggests that all physicians may benefit from utilizing the torque tool.
The simulator setup used for this study is limited by a stationary, non-beating heart, providing a simpler environment than in clinical settings, making it difficult to fully assess catheter stability [
16]. The consistent measured performance metrics and improved perception with and without the torque tool, along with the reduction in muscle usage, suggests that the catheter torque tool may improve catheter control in a clinical environment, which has additional cardiac and respiratory movements that affect catheter stability [
11]. In more complex clinical settings, the reduction in muscle usage may be compounded in subsequent lesions, requiring physicians to hold catheters on lesion locations with more consistent contact. Improved catheter contact when creating lesions has been shown to produce more successful arrhythmia cures [
20] and reduce the risk of complications, especially in pediatric populations and patients with complex anatomy and CHD [
21]. Future work will be necessary to assess catheter stability and contact with the use of the novel torque tool in a clinical environment. Additionally, due to the short nature of this study, future work should be considered to evaluate the impact of using the novel torque tool when experienced physicians complete repetitive and/or more complex movements for an extended period of time as is typically experienced during cardiac ablation procedures.
The torque tool was not tested in conjunction with a long, steerable sheath, and future work may be of interest to compare performance differences between the two methods to improve catheter maneuverability and stability. Steerable sheaths have been shown to reduce procedure time for some procedures, though they do not appear to have an effect on procedural success and are noted to increase procedure cost [
22].