Methods and apparatus are provided for renal neuromodulation using a pulsed electric field to effectuate electroporation or electrofusion. It is expected that renal neuromodulation (e.g., denervation) may, among other things, reduce expansion of an acute myocardial infarction, reduce or prevent the onset of morphological changes that are affiliated with congestive heart failure, and/or be efficacious in the treatment of end stage renal disease. Embodiments of the present invention are configured for percutaneous intravascular delivery of pulsed electric fields to achieve such neuromodulation.

Methods and apparatus for renal neuromodulation

A device and method for ablating tissue is disclosed comprising the steps of acquiring an anatomical image of a patient, correlating the image to the patient, guiding an ablating member within the patient while tracking the position of the ablating member in the patient, positioning the ablating member in a desired position to ablate tissue, emitting ablating energy from the ablating member to form an ablated tissue area and removing the ablating member from the patient.

Methods of using high intensity focused ultrasound to form an ablated tissue area containing a plurality of lesions

The Journal of the Acoustical Society of America

A method and apparatus for treatment of heart failure, hypertension and renal failure by stimulating the renal nerve. The goal of therapy is to reduce sympathetic activity of the renal nerve. Therapy is accomplished by at least partially blocking the nerve with drug infusion or electrostimulation. Apparatus can be permanently implanted or catheter based.

Renal nerve stimulation method and apparatus for treatment of patients

Inferring upper-mantle temperatures from seismic velocities

A cardiac ablation device treats atrial fibrillation by directing and focusing ultrasonic waves into a ring-like ablation region (A). The device desirably is steerable and can be moved between a normal disposition, in which the ablation region lies parallel to the wall of the heart for ablating a loop-like lesion, and a canted disposition, in which the ring-like focal region is tilted relative to the wall of the heart, to ablate only a short, substantially linear lesion. The ablation device desirably includes a balloon reflector structure (18, 1310) and an ultrasonic emitter assembly (23, 1326), and can be steered and positioned without reference to engagement between the device and the pulmonary vein or ostium. A contrast medium (C) can be injected through the ablation device to facilitate imaging, so that the device can be positioned based on observation of the images.

Cardiac ablation devices

Ultrasonic interferometric measurements of the shear elastic properties of MgSiO3 perovskite were conducted on three polycrystalline specimens at conditions up to pressures of 8 gigapascals and temperatures of 800 kelvin. The acoustic measurements produced the pressure (P) and temperature (T) derivatives of the shear modulus (G), namely (∂G/∂P)T = 1.8 ± 0.4 and (∂G/∂T)P = −2.9 ± 0.3 × 10−2 gigapascals per kelvin. Combining these derivatives with the derivatives that were measured for the bulk modulus and thermal expansion of MgSiO3 perovskite provided data that suggest lower mantle compositions between pyrolite and C1 carbonaceous chondrite and a lower mantle potential temperature of 1500 ± 200 kelvin.

http://science.sciencemag.org/content/sci/281/5377/677.full.pdf

Ultrasonic shear wave velocities of MgSiO3 perovskite at 8 GPa and 800 K and lower mantle composition

Garnets with compositions between majorite and pyrope, Mj38, Mj48, Mj75 and Mj79 were synthesized at high pressures and temperatures in a 2000-ton uniaxial split-sphere apparatus (USSA-2000) and investigated using high resolution synchrotron X-ray powder diffraction and transmission electron microscopy. The results from both techniques are consistent with the tetragonal field for these garnets extending to a majorite composition just below Mj75. The cubic-tetragonal structural phase transition in garnet along the majorite-pyrope join is sensitive to both composition and temperature and is expected to result in anomalous behavior in elastic shear moduli. This phase transition may occur in the transition zone of the earth's mantle and will have important effects on the elastic and rheological properties of this region where these garnets are stable phases.

The symmetry of garnets on the pyrope (Mg3Al2Si3O12)-majorite (MgSiO3) join

Polycrystalline specimens in the CaTiO3–CaSiO3 perovskite system have been hot-pressed in a 2000-ton uniaxial split-sphere apparatus (USSA-2000) at pressures up to 15 GPa and temperature of 1550°C, for the compositions CaTiO3, Ca(Ti0.75Si0.25)O3, Ca(Ti0.5Si0.5)O3. For the specimens with the bulk densities within 1% of the X-ray density, compressional and shear wave velocity measurements have been conducted using ultrasonic interferometry. The measured adiabatic bulk moduli (K

 s
 ) for the CaTiO3 and Ca(Ti0.5Si0.5)O3 perovskites are 175(1) and 188(1) GPa and shear moduli (G) of 106(1) and 109(1) GPa. In situ X-ray diffraction studies at high pressure and temperature resulted in isothermal values for K
0 of 170(5) and 185(5) GPa, respectively. For the unquenchable CaSiO3 perovskite, elasticity theory and systematics were used to predict K
0=212(7) GPa and G
0=112(5) GPa; this shear modulus is 37% less than that for (Mg,Fe)SiO3 perovskite, suggesting that CaSiO3 perovskite cannot be ignored in modeling the composition of the Earth’s lower mantle.

Elasticity of CaTiO 3 –CaSiO 3 perovskites

Acoustic measurements of compressional (P) and shear (S) wave travel times were performed in a 1000-ton uniaxial split-cylinder apparatus (USCA-1000) of the Kawai-type up to 10 GPa at room temperature, using dual mode lithium niobate transducers and ultrasonic interferometry. The cell pressures were calibrated continuously by in-situ measurements of the travel times in a single crystal San-Carlos olivine buffer rod inside the cell assembly. Elastic compressional and shear wave velocities in a dense, fine-grained polycrystalline Al2O3 were measured simultaneously to 10 GPa; from these data, the elastic moduli and their pressure derivatives were obtained for the longitudinal modulus {L 0 = 461(3) GPa, L 0′ = 7.0(1)}, the shear modulus {G 0 = 162(2) GPa, G 0′ = 1.9(1)} and the bulk modulus {K 0 = 245(3) GPa, K 0′ = 4.5(1)}.

Yegor Sinelnikov

Papers

Cardiac ablation devices

Ultrasonic shear wave velocities of MgSiO3 perovskite at 8 GPa and 800 K and lower mantle composition

The symmetry of garnets on the pyrope (Mg3Al2Si3O12)-majorite (MgSiO3) join

Elasticity of CaTiO 3 –CaSiO 3 perovskites

Dual mode ultrasonic interferometry in multi-anvil high pressure apparatus using single-crystal olivine as the pressure standard