US Patent 7082335 Multipolar pacing method and apparatus

A physiological pacing system including a physiological pacing lead having an electrode array and a means for fixation, including a collar for securing the fixation means to a lead body of the pacing lead, is inserted into a bore within a heart wall at a physiological pacing site. The system further includes a means to create the bore, the means being a piercing tip, which is either coupled to a piercing tool or the pacing lead. The piercing tool may be an elongated hollow shaft into which the pacing lead is slideably insertable or a stylet wire, which is slideably insertable within a lumen of the pacing lead. Once the electrode array is implanted within the bore, a first pair of electrodes is selected for sensing and a second pair of electrodes is selected for pacing.