Methods for monopolar renal neuromodulation

#All publications and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference.

#The present invention relates to methods and apparatus for neuromodulation. In some embodiments, the present invention relates to methods and apparatus for achieving monopolar renal neuromodulation.

#Congestive Heart Failure (“CHF”) is a condition that occurs when the heart becomes damaged and reduces blood flow to the organs of the body. If blood flow decreases sufficiently, kidney function becomes altered, which results in fluid retention, abnormal hormone secretions and increased constriction of blood vessels. These results increase the workload of the heart and further decrease the capacity of the heart to pump blood through the kidneys and circulatory system.

#Several embodiments of the present invention will be apparent upon consideration of the following detailed description, taken in conjunction with the accompanying drawings, in which like reference characters refer to like parts throughout, and in which:

#FIG. 1 is a schematic view illustrating human renal anatomy.

#FIG. 2 is a schematic isometric detail view showing the location of the renal nerves relative to the renal artery.

#A. Overview

#Several embodiments of the present invention are methods and apparatus for neuromodulation via a pulsed electric field (“PEF”), a stimulation electric field, localized drug delivery, high frequency ultrasound, thermal techniques, athermal techniques, combinations thereof, and/or other techniques. In some embodiments, neuromodulation is achieved via monopolar (e.g., unipolar) methods and apparatus. Such neuromodulation may, for example, effectuate irreversible electroporation or electrofusion, necrosis and/or inducement of apoptosis, alteration of gene expression, action potential blockade or attenuation, changes in cytokine up-regulation and other conditions in target neural fibers.

#In some patients, when the monopolar neuromodulatory methods and apparatus of the present invention are applied to renal nerves and/or other neural fibers that contribute to renal neural functions, applicants believe that the neuromodulatory effects induced by the neuromodulation might result in increased urine output, decreased plasma renin levels, decreased tissue (e.g., kidney) and/or urine catecholamines (e.g., norepinephrine), increased urinary sodium excretion, and/or controlled blood pressure. Furthermore, applicants believe that these or other changes might prevent or treat congestive heart failure, hypertension, acute myocardial infarction, end-stage renal disease, contrast nephropathy, other renal system diseases, and/or other renal or cardio-renal anomalies. The methods and apparatus described herein may be used to modulate efferent or afferent nerve signals, as well as combinations of efferent and afferent nerve signals.