A new transvenous lead for both atrial and ventricular pacing

A new transvenous tined unipolar lead (Medtronic SP 342) has been implanted in 56 patients; 35 leads were positioned in the atrium and 34 in the ventricle. The lead comprises a trifilar DBS-conductor within an insulation of polyurethane, four symetrically placed polyurethane tines furnished with scallops and a platinum-iridium ring-tipped electrode. The scallops in the tines ensure flexibility and a small effective diameter of the lead which makes the choice of vein less critical than with most previous tined leads. It allows use of the same normally sized vein for a second lead for dual-chamber sensing pacing. Mean atrial and ventricular electrogram amplitudes (+/-SD) were 4.6 +/- 1.2 mV and 8.8 +/- 4.4 mV; mean atrial and ventricular stimulation thresholds were 0.8 +/- 0.3 V and 0.4 +/- 0.2 V; and mean atrial and ventricular lead impendances were 415 +/- 114 ohms and 456 +/- 105 ohms, respectively. The results of this study show that the SP 342 lead is useful especially in dual chamber systems.