1. Experimental Studies With a 9 French Forward-Looking Intracardiac Imaging and Ablation Catheter Developed in an NIH Supported Bioengineering Research Partnership Grant Program
David J. Sahn, 1Kalyanam Shivkumar, 1Aman Majahan, Muhammad Ashraf, Long Liu, 2Jonathan Cannata, 3Xunchang Chen, 4Raymond Chia, 5Aaron Dentinger, 6Matthew O'Donnell,
2K. Kirk Shung, 7Douglas N. Stephens, 5Kai Thomenius
Oregon Health & Science University, Portland, OR; 1University of California, Los Angeles, CA; 2University of Southern California, Los Angeles, CA; 3University of Michigan, Ann Arbor, MI; 4Irvine Biomedical, Inc., Irvine, CA; 5GE Global Research, Schenectady, NY; 6University of Washington, Seattle, WA; 7University of California, Davis, CA

2. Funded by NHLBI Bioengineering Research Partnership grant R01 HL67647
Disclosures
No relationships to disclose:
Kalyanam Shivkumar; Aman Majahan;
Muhammad Ashraf; Long Liu; Jonathan Cannata;
Xunchang Chen; Matthew O’Donnell; K. Kirk Shung;
Douglas N. Stephens
Employed by Irvine Biomedical, Inc.:
Raymond Chia
Employed by GE Global Research:
Aaron Dentinger; Kai Thomenius
Occasional consultant to IBI & GE:
David J. Sahn
Funded by NHLBI Bioengineering Research Partnership grant R01 HL67647

3. Background electromagnetic localization
Transcatheter treatment of arrhythmias by ablation has been targeted in more complex procedures in recent years
Fluoroscopy was the major alternative imaging method
To shorten long procedures, modern EP employs
electromagnetic localization
non-contact mapping
magnetic catheter manipulation
other means of imaging
multi-modality integration of 3D anatomy and intracardiac ultrasound

4. Background
Our Bioengineering Research Partnership has proposed and developed new intracardiac imaging and therapy devices for EP ablation and monitoring resynchronization lead placement
First device: side-looking catheter
very agile
64-element broadband phased array
EP recording electrodes
has been interfaced with NavX electrofield localization
to aid its positioning
This paper presents our results with the recently completed forward-looking 9 French catheter device which has a 24-element array on the tip of the catheter, extreme agility

5. Catheter Used Forward-looking 9 French catheter device
24-element array on the tip of the catheter
center frequency of 14 MHz
array pitch of 0.065
elements are 1.2 mm in elevation
extreme agility
Designed for near-field imaging
incorporates very high frame rates and …..
Bonding of elements to flex circuit extremely challenging
shorting occurred at bend points of original flex circuit
longer flex used

6. Catheter Used Enlarged headshaft Fitted with a second shaft electrode
used to provide anchoring ports
one to stabilize catheter in front of tissue
second port for thermister to verify temperature heating
Fitted with a second shaft electrode
allows integration of localization with NavX mapping

7. Methods Ultrasound imaging with single plane fluoroscopy
Microlinear probe introduced through both femoral artery and jugular veins
Three pigs (40-50 pounds) imaged from right atrium and right ventricle
One pig (40-50 pounds) imaged from two locations in right ventricle

8. Results Ablation could be localized by: tissue character change
vaporization
bubble formation
mechanical changes in behavior of tissue

9. Discussion First two devices built with piezoelectric ceramic
cMUT (computer micromachined ultrasound transducer) version of microlinear array completed
cMUTs are wave of the future for intraluminal, intracavitary ultrasound
Additional plans for microlinear array
extrudable RF ablation electrode
adaptation of both ceramic and cMUT versions for HIFU

10. Conclusion Efforts aimed at providing tools that offer
ultrasound guidance using 2D and 3D ultrasound
ability to deliver RF HIFU ultrasound energy from the same device
providing integrated ability to evaluate changes in mechanical properties, muscle function and tissue temperature
Changes in fundamental transducer materials and connectors as well as microflex low profile cabling with slip layers
improve steerability, flexibility and decrease the cost of providing intracardiac ultrasound guidance in patients.