New generation of transvenous left ventricular leads - first experience with implantation of multipolar left ventricular leads.

BACKGROUND: Aside from unfavourable anatomy, inacceptable pacing thresholds and phrenic nerve stimulation represent major obstacles for successful left ventricular (LV) lead placement for cardiac resynchronization therapy (CRT).

OBJECTIVE: To implant, for the first time, a new generation of transvenous multipolar LV leads (a quad-electrode lead) in combination with a CRT-cardioverter defibrillator, and to demonstrate that this combination allows for 10 different pacing vectors to combat the problems cited above.

METHODS: Thirty patients were selected for CRT-cardioverter defibrillator implantation. At implantation, standard lead parameters were recorded. The reason for choosing a vector other than the standard bipolar vector for LV pacing, the LV lead implantation time, x-ray exposure time required for lead placement, and the reason for and number of repositions were documented. Before hospital discharge, a system inspection was performed.

RESULTS: The implantation lead parameters were satisfactory. In 17 patients, a vector other than the standard bipolar vector was chosen to avoid phrenic nerve stimulation or to establish a better pacing threshold. In seven cases, the LV lead was repositioned (three phrenic nerve stimulations, two inacceptable pacing captures and two nonstable lead positions). Phrenic nerve stimulation was noted in eight cases; however, in five, this was eliminated by changing the stimulation vector. At hospital discharge, two-thirds of patients retained the implantation stimulation vector and in one-third, the vector was modified to further optimize the system.

CONCLUSIONS: The quad-electrode lead provides good handling and may reduce the risk of inacceptable pacing thresholds and phrenic nerve stimulation. Consequently, implantation time, x-ray exposure and contrast agent load may be decreased, leading to lower kidney stress. Furthermore, the option for vector change after implantation may reduce the number of necessary reinterventions resulting from the pacing threshold and impedance increase.