Atrial stimulation using floating electrodes and a counter electrode in the vena cava superior.

Multi-chamber stimulation using floating electrodes of a single-pass lead h as become an increasingly explored field in the electrotherapy of the heart , with potential applications for bradycardia, as well as low-energy tachyc ardia prevention and therapy. The aim of this investigation is to validate the performance of the novel vena cava-atrial stimulation (VECATS) concept. The new VECATS single-pass lead provides usual bipolar sensing combined wi th atrial pacing with respect to a counterelectrode in the vena cava superi or (VCS). Measurements performed from the time of implantation to the 2-mon th follow-up show consistent P-wave amplitudes, stable atrial capture thres holds around 3.0 V, and a high safety margin of at least 132 % between the atrial and the diaphragmatic thresholds. These promising initial results pr ove that this mode of pacing is a feasible method.