Patent ID: 8718794

Claim:
A method for implanting an implantable active fixation medical lead, the method comprising: delivering a lead body distal portion to an implantation site, the lead body distal portion having a distal end with a first radiopaque marker; and observing via fluoroscopy a proximal displacement of a second radiopaque marker of a protuberance as a tissue fixation helical anchor is progressively embedded into cardiac tissue, the protuberance having a fixed proximal end, a free distal end and a body intermediate the fixed proximal end and free distal end, the protuberance extending distally from the lead body distal portion, the protuberance being moveable relative to the lead body distal portion, the fixed proximal portion of the protuberance extending outwardly from the lead body distal portion at a location proximal to the distal end of the lead body distal portion, and the free distal end of the protuberance having the second radiopaque marker; wherein the protuberance has a stress concentration site that facilitates the protuberance deflecting in a desired direction; wherein when the tissue fixation helical anchor is increasingly embedded in the cardiac tissue, the cardiac tissue displaces the free distal end of the protuberance and causes the second radiopaque marker to be directed towards the first radiopaque marker; and wherein when the tissue fixation helical anchor is fully embedded in the cardiac tissue, the cardiac tissue fully displaces the free distal end of the protuberance and causes the second radiopaque marker to be adjacent the first radiopaque marker.