Pullout His bundle/electrophysiologic studies using leads previously inserted via the subclavian vein

Conventional electrophysiologic studies involve the insertion of several catheter electrodes, positioned to pace and record from the high right atrium, His bundle region, and the right ventricular apex. The present study was undertaken to determine whether similar information could be obtained during removal of temporary pacing leads previously inserted via the subclavian vein, without the need for further invasive studies. Attempts to record a His bundle potential were successful in 157 of 200 patients (79%). A His bundle potential could be recorded during low right atrial pacing on 24 of 58 attempts. The Wenckebach cycle length was compared during high and low right atrial pacing in 34 patients, and did not differ significantly. Ventricular stimulation from the right ventricular apex and right ventricular inflow tract could be performed for assessment of ventricular vulnerability. Similarly, high right atrial pacing for sinus node testing was readily accomplished. In conclusion, detailed electrophysiologic studies can be performed during termination of temporary pacing, in sufficient detail to provide results equivalent to those of a more formal study.