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
  doctors 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
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