Ventricular Lead in Atrial Position

Summary

Longterm function and stability of atrial leads is still a crucial part of dual chamber pacing and sensing. The use of the same type of electrode in the atrium and in the ventricle is an advantage and simplification from technical, surgical and logistic standpoints. We report about the results in 158 consecutive Helifix electrodes in atrial position and 143 Helifix electrodes in ventricular position in the same patients. The 158 patients (85 males, 43 females, mean age 63.5) received a pacemaker system with only atrial sensing (VAT of VDD) in 31%, with atrial pacing and sensing (AAI or DDD) in 44% and with atrial pacing but ventricular sensing only (DVI) in 25%. Electrodes were transvenously inserted via cephalic or subclavian vein. Atrial electrodes were placed underneath the crista terminalis of the lateral right atrium and not in the atrial appendage, the ventricular leads in the right ventricular apex. Atrial threshold at impulse duration of 1.0 ms was 0.85 V (0.37–2.04) and 1.11 rnA (0.4–2.0), P-wave was 3.21 mV (1.0–9.5). Ventricular threshold at 1.0 was 0.67 V (0.25–1.70) and 0.89 mA (0.25–2.1), R-wave was 7.9 mV (1.3–20.0). After mean follow-up of 18.2 months overall complication rate was 3%. 3 early displacements (2 within 24 hours and I after 3 months). We observed one case of phrenic nerve stimulation. From these results we conclude that an electrode primarily designed for ventricular use is extremely suitable for longterm atrial sensing and stimulation and overall complication is not increased in dual chamber pacing.