Management
Despite guideline-directed medical therapy his heart failure symptoms persisted. Considering the LV impairment and dyssynchronous ventricular activation, he was offered a device upgrade to a CRT-P with either a conventional LV lead or a His bundle lead, in addition to an RA lead to improve VV and AV synchrony, respectively. Prior to implantation left sided venography was performed to evaluate vein patency which showed an occluded subclavian vein (Figure 1). Options considered included: 1) a contralateral CRT-P implantation; 2) implanting a right sided RA and LV lead and tunneling across to the left; 3) venoplasty facilitated CRT-upgrade; 4) lead extraction of the functional RV lead for re-canalisation and upgrade; 5) a conservative approach. After careful discussion, the patient elected to proceed with an upgrade strategy (including venoplasty and lead extraction).
As a centre with experience in His Bundle pacing (HBP), and in alignment with recent AHA/ACC guidelines (1), we targeted CRT-P via this approach. The least aggressive strategy was preferable and therefore prior to opening the left-sided pocket, the SCV occlusion was probed in a retrograde manner using a multipurpose catheter (6F MPA1 Impulse, Boston Scientific, Mass) from right femoral venous access (secured for temporary pacing wire support). In doing so, we were able to direct the catheter to the brachio-cephalic vein and define the occlusion in detail. Furthermore, contrast highlighted a large collateral branch, which we felt could be punctured directly from a left sub-clavicular approach (Figure 1). We left a 0.035in J wire in this branch, and successfully secured venous access through the Seldinger technique (Figure 2, Video 1). A passive lead to the right atrial appendage was implanted and a 69cm Select Secure 3830 lead (Medtronic Inc, MN) was deployed via a C315 sheath (Medtronic) at the His bundle.
Intracardiac electrograms confirmed underlying complete AV dissociation with an intrinsic His-QRSend interval of 192ms. With HBP, non-selective capture was achieved resulting in a shortened Stim-QRSend of 158ms with a threshold of 1V at 0.5ms (Figure 3). The device was programmed DDD-60 with an “LV” to RV delay of 60ms, to allow protective back up RV pacing in the event of loss of His capture. There were no complications and post procedural 12-lead ECG confirmed non-selective His capture.