SBIR-STTR Award

Sudden cardiac death kills 300,000 people in the United States yearly. More than half of these deaths are caused by arrhythmias including ventricular tachycardia. Currently there is no safe, effective and inexpensive method for treating most ventricular tachycardias. Thermal ablation using radiofrequency or laser heating can effectively treat supraventricular tachycardia, but the lesions are too small to treat most VTs, especially those that originate from infarct scars. Two effects limit the lesion size. First, the energy is absorbed in a thin layer of tissue surrounding the therapy tool. Second, thermal conduction is too small to carry the energy deeper into the tissue. We have developed saline-enhanced ablation, which uses infusion of warm saline through the myocardium (simultaneous with the application of heating energy) to increase the tissue thermal transport by a factor of 20 or more. We have shown that this method can increase the volume of thermal lesions in liver cancer by a factor of l00. We will adapt our system to test the improvement it provides to RF and laser heating of myocardium. The method that creates the largest, deepest lesions will be used for continued development in Phase 2. Proposed Commercial Applications: The goal of this project is to develop a system and associated therapy protocols that can safely heat large regions of myocardium. This will be useful for treating ventricular tachycardia, especially VT following myocardial infarction, which typically requires large ablation lesions.

Sudden cardiac death kills 300,000 people in the United States yearly. More than half of these deaths are caused by arrhythmias including ventricular tachycardia. Radiofrequency ablation, which successfully treats supraventricular tachycardia, is not successful at treating ventricular tachycardia because conventional RF ablation catheters cannot treat a large enough volume of myocardium. In Phase 1 of this project, we have demonstrated the feasibility of saline-enhanced ablation. We will have used infusion of warm saline through the myocardium (simultaneous with the application of radiofrequency or laser heating energy) to increase the tissue thermal transport by a factor of 20 or more. We have shown that this method can increase the volume of thermal lesions in myocardium by a factor of 12. These lesions are capable of treating the full thickness of the myocardium, and therefore show promise toward treatment of ventricular tachycardia. We will continue the development of this system during this Phase 2 project. Based on the Phase 1 results we will continue our development using saline enhanced radiofrequency ablations. We will develop a steerable catheter that will have a porous radiofrequency electrode at the tip, which will be inserted into the myocardium. The catheter will have a central lumen with an RF heater to heat the saline before injecting it into the myocardiurn. We will qualify this prototype catheter and system in preclinical studies of ventricular tachycardia in animal models at the Mayo Clinic and the Brigham and Women's Hospital.

Thesaurus Terms:
biomedical equipment development, heart catheterization, laser, radiowave radiation, saline, tachycardia electrode, laser therapy, method development, myocardium, temperature, thermometry swine