Scientific Data

Venice Arrhythmias 2007
Venice, Italy
Presented by Arjun Sharma, MD

CyberHeart: Total Non-invasive Therapy for Cardiac Arrhythmias using Stereotactic
Radiosurgery: Ablation lesion creation

Arjun Sharma, MD, Patrick Maguire, MD, PhD, Douglas Wong, MD, Thilaka Sumanaweera, PhD, James Marshall, DVM, James Steele, Louis Fajardo, MD, Patricia Takeda, MD and Thomas Fogarty, MD. Sutter Medical Research Institute, Sacramento, CA, CyberHeart, Menlo Park, CA, The Community Medical Center, Fresno, CA, Stanford University, Palo Alto, CA, and Regional Cardiology, Sacramento, CA. USA

Introduction: Catheter based techniques for arrhythmia ablations require intravascular intervention with limitations, and potential complications. We used externally focused stereotactic radiation to alter cardiac electrophysiologic and histologic properties, for the future clinical application of ablating arrhythmias.

Methods: Externally focused radiation of atrial tissue was studied in Hanford-Sinclair mini swine (n=8)(40-70kg). The radiation (x-rays, 20-60 Gy) was targeted (pulmonary vein orifice and cavo-tricuspid isthmus) using a computer controlled robotic arm, which directed a linear accelerator (Cyberknife). Cardiac and respiratory motion compensation was used. Post treatment, cardiac assessment with TEE and cardiac mapping with CARTO (Biosense) took place. The animals were sacrificed and pathology specimens taken.

Summary of Results: All animals survived treatment. Radiation effects appeared to be time and dose dependent. Radiation directed at specific areas resulted in uniform attenuation of signal amplitude. No pulmonary vein stenosis was seen. Cardiac function was preserved. No adverse effect was noted in surrounding tissues.

Conclusions: External stereotactic radiosurgery produces focused electrophysiologic and histologic change. Energy can be directed to any cardiac tissue with 1-2 mm accuracy.