Electrophysiology

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

2. 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

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

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

5. Current State of the ArtRobotic • Hansen Medical • Robotically Controlled Catheter ME294: Medical Device Design Autumn 2005 Bark, Dreissigacker, Sanchez, Santos

6. 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

7. 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

8. 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

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

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

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

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

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

14. 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

15. 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

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