A method for the treatment of a patient for the purpose of lowering blood pressure and/or treating cardiac arrhythmias, particularly atrial fibrillation includes the insertion of an ablation catheter into the lumen of a renal artery. The ablation catheter is equipped with an electrode that can stimulate the wall tissue in the renal artery to help identify the location of a renal nerve. High-frequency stimulation of the renal nerve causes a decrease in the blood pressure of the patient thereby indicating that a renal nerve is nearby. The ablation catheter is used to ablate the renal nerve using radiofrequency, ultrasound, microwave energy or cryogenic cooling. An irrigated ablation catheter may be used to decrease damage to cells in the wall of the lumen of the renal artery other than the renal nerve, such as the endothelial cells. In order to treat atrial fibrillation an ablation catheter would be used to isolate one or more pulmonary veins in order to reduce propagation of the aberrant electrical signals capable of producing atrial fibrillation.
