Cambridge Design Partnership recently announced it is working with Kings College London to further develop a new steerable catheter designed to treat complex cardiac arrhythmias such as atrial fibrillation and ventricular tachycardia. The catheter, created by a group of biomedical engineers from King’s College London, and now refined for commercial manufacture by Cambridge Design Partnership, will enable delivery of radiofrequency energy and is expected to quickly and efficiently reach specific ablation targets within the heart, with three degrees of freedom and the ability to be guided robotically under MRI imaging.
Cardiac Rhythm News spoke to Kawal Rhode, lead for development of novel technologies for minimally-invasive cardiac interventions at King’s College London, and Matt Brady, head of Medical Therapy at Cambridge Design Partnership, in more detail about this novel catheter.
What is the need to develop this type of ablation catheter?
Cardiac arrhythmias affect two million people a year in the UK alone, with atrial fibrillation being the most common. Arrhythmias which are resistant to early (cardioversion) treatment are treated by catheter ablation to eliminate spurious conduction paths within the heart tissue itself.
The future of this treatment is likely to require more precise and sparing delivery, thereby providing a much-needed boost to success rates whilst retaining greater cardiac function. The new catheter is able to quickly and efficiently reach specific ablation targets within the heart, with three degrees of freedom and the ability to be guided robotically under MRI imaging.
What type of arrhythmias can be treated with this catheter?
The King’s College London (KCL) device has been designed to treat more efficiently both atrial fibrillation and even more challenging conditions such as ventricular tachycardia, for which the emerging consensus for earlier intervention by ablation (Aliot EM et al, Europace 2009 (11):771‒817) must be set alongside an acknowledgement of the significant demands catheter ablation of ventricular tachycardia currently places on the skill and experience of the electrophysiologist.
How many years has the technology been in development for?
The technology was devised by a group of senior King’s College London staff in the Biomedical Engineering Department, in 2011. In 2013, the King’s Commercialisation Institute selected the project to receive their financial and staff support to translate the project into clinical use, which enabled the development of the current prototype.
What are the main features of this catheter?
The KCL catheter has been developed to access the full inner surface of the targeted chamber of the heart and consistently deliver the contact forces necessary to create transmural lesions with a highly repeatable behaviour, enhancing consistency of both position and contact force in the hands of a skilled electrophysiologist. The design of this catheter also leads the way towards robotically enhanced control and imaging for challenging procedures not feasible today.
In order to achieve these goals, the KCL catheter is steerable in all four directions, whilst allowing adjustment of the length of the steerable section in real time to access a full 360-degree sphere without torqueing or excessive axial repositioning. The materials and construction have been developed to significantly reduce the positional inconsistency introduced by “material set” which means, for example, that existing catheters do not return to straight when steering force is removed. Therefore, the KCL catheter should be capable of reaching targets in more challenging topographies, more quickly and consistently, and with increased control of contact force – which remains a crucial ingredient for success even after the advent of “force-time integral” ablation controls.
What are the main differences compared with other ablation catheters in the market?
Competitor catheters examined during the development were not MRI-compatible, and were limited to single-direction bending of a fixed steerable length plus twisting of the catheter shaft itself to access different areas. In addition, the “material set” behaviour inherent in the construction of these catheters meant that even without twisting repeated actuation led to different catheter positions. All this leads to variability in tip position response and tip force control, even in response to identical proximal inputs. Whilst highly skilled electrophysiologists are capable of adapting to these issues to a significant extent in current procedures, overcoming these limitations is likely to be a key step towards more efficient procedures, better access to challenging topologies, and ultimately, the effective robotically enhanced controls that are likely to be required for effective ablation treatment of ventricular tachycardia.
Have you performed any pre-clinical studies with this catheter?
The product is currently at a prototype stage and is undergoing performance verification in the lab. The next step will be to carry out pre-clinical trials.
What are the next steps of development?
Once laboratory performance testing is completed, it is likely that a further design iteration will be necessary to ensure the device is suitable for pre-clinical trials. These will consist of validating the manoeuvrability, position and force control in-vivo. Future pre-clinical trials could involve modifying the catheter to make electrophysiological measurements or ablation studies.
Kawal Rhode is professor of Biomedical Engineering at King’s College London, London, UK. Matt Brady is head of Medical Therapy, Cambridge Design Partnership, Cambridge, UK
