Abstract 2170: Unipolar Pace Mapping With the Medtronic SelectSecure 3830 Lead System can Accurately Locate the HIS Bundle for Permanent HIS Bundle Pacing
Introduction: Permanent HIS Bundle pacing (HBP) is one of the most physiological ventricular pacing strategies available. Its wide spread adoption is limited due to challenges in HIS mapping, and requires femoral EP mapping to guide lead placement. We investigate whether unipolar pace mapping (PM) using the lead alone is a viable technique to locate the HB for lead deployment.
Methods: Patients indicated for ventricular pacing were approached for HBP. An active fixation lead (SelectSecure®3830, Medtronic) inserted through its deflectable sheath was advanced to the right atrium via left pectoral approach.The cathode tip was positioned just outside the tip of the sheath. Unipolar PM was applied at 5V/0.5ms along the tricuspid septal annulus in anterior posterior direction. At the location with 12/12 ECG match to intrinsic QRS, and with pace to QRS delay >30ms, the lead was fixed. Unipolar sensing for HB electrogram was performed with the Medtronic 2090 analyzer (unfiltered, variable gain, sweep speed 50mm/sec). HBP implant thresholds, HB lead implant and fluoroscopy times, intrinsic and paced HV intervals, pre and post QRS and PR intervals were collected. Paired Student t-test was used for analysis.
Results: 22 patients (16 male, mean age 69 yrs) underwent HBP. 19 patients had successful HBP, with 3 patients having para-Hisian septal pacing. The mean HBP implants threshold, HB lead implant and fluoroscopy times were 1.67±44V/0.6ms, 43±26min, and 13±12min respectively. The mean intrinsic and paced HV intervals were 60 and 44 ms respectively. After HBP, the QRS duration decreased from 160±44 to 132±43ms (p<0.01). HBP corrected one RBBB, one LBBB, and three right ventricular apical pacing complexes to normal (<120ms) and accounted for the shorter post HBP mean QRS duration. 8 patients presented with PR intervals ≥200msec and had their PR interval narrowed from a mean of 326±141 to 174±21ms (p<0.05).
Conclusions: Unipolar PM of the His bundle using the Medtronic SelectSecure® lead system alone can accurately locate the HB for HBP with acceptable implant time and pacing thresholds. HBP also has the potential value of AVN and ventricular electrical resynchronization benefit. More data with longer-term follow up are needed before considering wide spread adoption.