THE RIGHT ATRIAL FREE WALL - AN ALTERNATIVE PACING SITE

A major advantage of active fixation permanent pacing leads is their ability to be actively attached in areas where conventional passive fixation leads cannot be. In a review of records of 134 consecutive patients requiring dual chamber pacing, all of whom received active fixation atrial leads, 56 had right atrial appendage (AA) pacing and 78 had right atrial free-wall (AFW) pacing. Acute electrical parameters including sensed P wave amplitude (AA = 5.6 +/- 2.3 mV, AFW = 5.5 +/- 2.3 mV), slew rate (AA = 1.21 +/- 0.77 V/sec, AFW = 1.20 +/-0.74 V/sec), stimulation thresholds (voltage and current) including rheobase voltage (AA = 0.6 +/- 0.2 V, AFW = 0.6 +/- 0.2 V), and pacing impedance (AA = 516 +/- 89 ohms, AFW = 504 +/- 84 ohms) were similar in both groups. There were two dislodgements (atrial appendage group) and no episodes of clinically important perforation or diaphragmatic stimulation. The free wall of the right atrium appears to be an excellent alternative pacing site to the appendage.