Targeting of cardiac autonomic plexus for modulation of intracardiac neural tone.

AIMS: Ventricular rate control is considered as an initial choice of therapy in many patients with atrial fibrillation (AF). We could previously show that electrostimulation of the right inferior ganglionated plexus (RIGP), which supplies the AV node, instantly decreases ventricular rate during AF. This study describes the development of a technique to reliably implant a chronic lead inside the RIGP. METHODS AND RESULTS: In nine mongrel dogs with AF, the RIGP was identified by neuromapping with probatory high-frequency stimulation (20 Hz) over steerable electrode catheters until a significant ventricular rate slowing was achieved. Then an active fixation, permanent pacemaker lead was fixed closed to the mapping catheter left in place as anatomical marker. Initially (n = 4) available guiding catheters and steerable lead stylets were employed to navigate and anchor the lead, which resulted in repetitive screw-in attempts. Therefore, a guiding catheter was developed, which allowed angiography, lead advancement through its lumen, and probatory neurostimulation over its tip. This tool allowed lead delivery within 40 min (n = 5). Neurostimulation via the permanent lead elicited negative dromotropic effects with stimulation frequency, voltage, and impulse duration as determinants of stimulation efficacy. CONCLUSION: Active fixation of a permanent pacing lead inside the RIGP is feasible without thoracotomy. Thereby, ventricular rate control during AF can be achieved with stimulus voltages applied for myocardial electrostimulation.