THE RIGHT ATRIAL FREE WALL - AN ALTERNATIVE PACING SITE

A major advantage of active fixation permanent pacing leads is their a bility to be actively attached in areas where conventional passive fix ation leads cannot be. In a review of records of 134 consecutive patie nts requiring dual chamber pacing, all of whom received active fixatio n atrial leads, 56 had right atrial appendage (AA) pacing and 78 had r ight atrial free-wall (AFW) pacing. Acute electrical parameters includ ing 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), sti mulation thresholds (voltage and current) including rheobase voltage ( AA = 0.6 +/- 0.2 V, AFW = 0.6 +/- 0.2 V), and pacing impedance (AA = 5 16 +/- 89 ohms, AFW = 504 +/- 84 ohms) were similar in both groups. Th ere were two dislodgements (atrial appendage group) and no episodes of clinically important perforation or diaphragmatic stimulation. The fr ee wall of the right atrium appears to be an excellent alternative pac ing site to the appendage.