A novel magnetic navigation system (MNS) allowing remote guidance of catheters and guidewires might assist in implantation of left ventricular (LV) pacing leads. To assess the feasibility of deploying a LV pacing lead into a coronary sinus (CS) side branch using a magnetically guided wire and of performing the procedure without a CS guiding sheath. Twenty-one patients were included in this study. Nine underwent CRT device implantation using a MNS to steer the guidewire (MNS group) while 12 patients were conventionally implanted (control group). In 6 patients in the MNS group, the procedure was performed using a CS guiding sheath. In 3 others, the decision was to perform the procedure without a CS sheath. In these patients the wire was advanced manually, while the external magnets oriented it toward the CS os. In the CS, "vector based" navigation was used to guide the wire to the desired side branch. In all 9 patients in the MNS group, the target vessel could be successfully engaged by the magnetically guided wire. In 7, the LV lead was lodged in the target vessel. In 2 patients, the LV lead was repositioned in an anterolateral side branch due to instability or inability to engage the vessel with it. Mean total procedure time was 164 +/- 58 minutes (without sheath 229 +/- 52 vs with sheath 132 +/- 26 minutes; P = 0.007). Mean fluoroscopy time was 28 +/- 9 minutes. For control patients, the procedure and fluoroscopy time were similar (144 +/- 41 minutes and 26 +/- 12 minutes, respectively). No major complications occurred. LV lead implantation can be performed using a remote magnetically steered guidewire. Though the lead could be implanted without a CS guiding sheath, longer procedure times were required.