Apparatus and Method for Controlled Depth of Injection into Myocardial Tissue

Abstract

An injector for delivering an injectate into the myocardium of the heart may be implemented as a catheter or a handheld unit. The injector includes a body, a stabilizer secured to a distal end of the body, and a needle that may be controllably advanced from the distal end of the body. The stabilizer stabilizes the distal end of the body relative to the myocardium while the heart beats. An enlarged region disposed along the needle prevents the needle from being advanced into the myocardium beyond a desired penetration depth. To make an injection, the physician brings the distal end of the body in proximity to the myocardium, actuates the stabilizer to stabilize the distal end relative to the myocardium, and advances the needle into the myocardium. Advancement of the needle is impeded by the enlarged region, thereby placing the needle tip at the desired penetration depth for the injection.

1 - 15 . (canceled) 
     
     
         16 . A method for administering an injectate into myocardial tissue of a heart in a body of a patient, comprising:
 advancing a distal portion of a body into proximity with the myocardial tissue;   stabilizing the body distal portion relative to the myocardial tissue;   advancing a needle from the stabilized body distal portion into the myocardial tissue until impeded by an enlarged region disposed along the needle at a predetermined distance from a tip thereof; and   administering the injectate into the myocardial tissue from an injection port in the needle distal of the enlarged region, wherein the injectate penetrates into the myocardial tissue at a predetermined distance from an epicardial or endocardial surface of the heart.   
     
     
         17 . The method of  claim 16  further comprising:
 retracting the needle from the myocardial tissue; 
 ceasing stabilization of the body distal portion relative to the myocardial tissue; and 
 withdrawing the distal portion of the body from proximity with the myocardial tissue. 
 
     
     
         18 . The method of  claim 17  comprising repeating the stabilizing, advancing, administering, retracting, and ceasing stabilization steps for a plurality of different locations in the myocardial tissue. 
     
     
         19 . A method for administering an injectate into myocardial tissue of a heart in a body of a patient, comprising:
 advancing a distal end of a catheter body through a thoracic cavity into proximity with an epicardial surface of the myocardial tissue;   stabilizing the distal end of the catheter body relative to the myocardial tissue;   advancing a needle from the stabilized distal end of the catheter body into the myocardial tissue until impeded at the epicardial surface by an enlarged region disposed along the needle at a predetermined distance from a tip thereof, to achieve a predetermined penetration depth; and   administering the injectate into the myocardial tissue from the tip of the needle, wherein the injectate penetrates into the myocardial tissue at the penetration depth.   
     
     
         20 . The method of  claim 19  wherein:
 the stabilizer comprises a helix; and 
 the actuating step comprises screwing the helix into the myocardial tissue to a fixation depth, the penetration depth of the needle being independent of the fixation depth of the helix. 
 
     
     
         21 . The method of  claim 20  further comprising:
 retracting the needle from the myocardial tissue; 
 unscrewing the helix from the myocardial tissue; and 
 withdrawing the distal end of the catheter body from proximity with the epicardial surface.