Electrophysiology Paul Wang, MD Amin Al-Ahmad, MD ME294: Medical Device Design Autumn 2005 Bark, Dreissigacker, Sanchez, Santos Power Steered Catheter Control System Karlin Bark, Marlo Dreissigacker, Gabriel Sanchez, Dan Santos

Electrophysiology and Arrhythmia Electro-physiologists detect abnormal electrical pathways in the heart by recording electrical activity within the heart chambers ME294: Medical Device Design Autumn 2005 Bark, Dreissigacker, Sanchez, Santos

Non-Surgical Procedure Catheter insertion point ME294: Medical Device Design Autumn 2005 Bark, Dreissigacker, Sanchez, Santos

Current State of the Art Manual ME294: Medical Device Design Autumn 2005 Bark, Dreissigacker, Sanchez, Santos Multi-Degree of Freedom – Bi-directional – Torsion Control – Telescoping Tip Increased Mapping Area – Ring of Contacts – Balloon Catheter

Current State of the Art Robotic Hansen Medical – Robotically Controlled Catheter ME294: Medical Device Design Autumn 2005 Bark, Dreissigacker, Sanchez, Santos

Clinical Need Finding Surgeon “wish-list” –More comfortable and simple to use –Easier control of distal tip –Finer positioning resolution of distal tip –Larger range of motion of distal tip –Tactile feedback Statements –“uncomfortable”, “tiring”, “fingers hurt”, “not intuitive at all” ME294: Medical Device Design Autumn 2005 Bark, Dreissigacker, Sanchez, Santos

Current design problems Simple mechanical designs: –Manual positioning limits accuracy –Physically taxing user-interface –Uncomfortable user-interface Advanced robotic designs: –Not intuitive –No direct tactile feedback –Requires re-training ME294: Medical Device Design Autumn 2005 Bark, Dreissigacker, Sanchez, Santos

Design Specifications Focus on manual input device that doctor uses Specifications: –Electromechanical - Smart Mechanical Drive –Bi-directional control –One-handed operation - familiar to doctors –In-line structure –Non-backdriveable ME294: Medical Device Design Autumn 2005 Bark, Dreissigacker, Sanchez, Santos

Smart Mechanical Drive ME294: Medical Device Design Autumn 2005 Bark, Dreissigacker, Sanchez, Santos Internal motor actuates push-pull cables based on doctor’s input Power Steering

Input Mechanism ME294: Medical Device Design Autumn 2005 Bark, Dreissigacker, Sanchez, Santos Linear Slide Axially Symmetric Low Friction

Electronics ME294: Medical Device Design Autumn 2005 Bark, Dreissigacker, Sanchez, Santos µController PIC Motor Driver Linear Sensor Limit Switches Power Supply Proportional Speed Control Dead-band Throttle Travel Limits

Demonstration ME294: Medical Device Design Autumn 2005 Bark, Dreissigacker, Sanchez, Santos

Design Improvements Decrease overall size Manual override Increase speed smaller diameter shorter length manual override larger pitch spring mechanism ME294: Medical Device Design Autumn 2005 Bark, Dreissigacker, Sanchez, Santos Advanced Control Self-Centering Ring

Conclusions Less physical effort to use Similar motion and interface: no additional training Could transition into real-world market easily –Minor change on existing, common device –Only a small increase in cost +$50 for a device that costs $600-$1000+ ME294: Medical Device Design Autumn 2005 Bark, Dreissigacker, Sanchez, Santos

Acknowledgements Dr. Paul Wang, Dr. Amin Al-Ahmed, Bryant Lin Craig Milroy and Raj Doshi Laura Melton ME294: Medical Device Design Autumn 2005 Bark, Dreissigacker, Sanchez, Santos

Questions? ME294: Medical Device Design Autumn 2005 Bark, Dreissigacker, Sanchez, Santos