An agent delivery needle catheter configured for injecting an agent at an injection site in a wall of a patient's body cavity, comprising: a) an elongated catheter shaft having a proximal end, a distal end, a tissue-contacting end face being the distal-most leading surface of the catheter and a needle-through lumen therein extending from the proximal end to a needle-through port in the distal end face of the catheter, the needle-through lumen being the single lumen of the catheter shaft open to outside of the catheter in a distal section of the shaft and the needle-through port being the single port in the distal tip section of the shaft, the distal end face being at least in part substantially perpendicular to a longitudinal axis of the distal section of the shaft such that the distal end face and needle-through port therein are configured to be pushed against the wall of the patient's body cavity, and the needle-through lumen has an angled distal portion which extends to the needle-through port at an angle greater than 0 degrees and less than 90 degrees relative to the longitudinal axis; and b) a hollow needle slidably disposed in the needle-through lumen of the shaft, having a piercing distal tip and a lumen in fluid communication with a port in the piercing distal tip, and having a retracted configuration in which the piercing distal tip of the needle is in the needle-through lumen of the shaft, and an extended configuration in which the piercing distal tip extends distally out the needle-through port, such that the catheter is configured to form an angled injection pathway in the wall of the patient's body cavity by directing the needle into the wall of the patient's body cavity at the angle of the angled distal portion of the needle-through lumen with the distal end face against the wall of the patient's body cavity at the injection site, characterized in that the needle-through lumen has a substantially uniform diameter along its entire length, and can slidably receive a straight needle or a preshaped bent needle therein, wherein the straight needle as well as the preshaped bent needle would emerge from the port at the same angle. a) an elongated catheter shaft having a proximal end, a distal end, a tissue-contacting end face being the distal-most leading surface of the catheter and a needle-through lumen therein extending from the proximal end to a needle-through port in the distal end face of the catheter, the needle-through lumen being the single lumen of the catheter shaft open to outside of the catheter in a distal section of the shaft and the needle-through port being the single port in the distal tip section of the shaft, the distal end face being at least in part substantially perpendicular to a longitudinal axis of the distal section of the shaft such that the distal end face and needle-through port therein are configured to be pushed against the wall of the patient's body cavity, and the needle-through lumen has an angled distal portion which extends to the needle-through port at an angle greater than 0 degrees and less than 90 degrees relative to the longitudinal axis; and b) a hollow needle slidably disposed in the needle-through lumen of the shaft, having a piercing distal tip and a lumen in fluid communication with a port in the piercing distal tip, and having a retracted configuration in which the piercing distal tip of the needle is in the needle-through lumen of the shaft, and an extended configuration in which the piercing distal tip extends distally out the needle-through port, such that the catheter is configured to form an angled injection pathway in the wall of the patient's body cavity by directing the needle into the wall of the patient's body cavity at the angle of the angled distal portion of the needle-through lumen with the distal end face against the wall of the patient's body cavity at the injection site,