Non-standard approach for device selection. Left bundle branch optimized ICD for patients with heart failure and LBBB

Cardiac resynchronization therapy is a well-proven non-surgical treatment option in patients with heart failure and LBBB. Left bundle branch area pacing (LBBAP) is novel and promising pacing modality which may lead to better clinical and echocardiographic response for resynchronization therapy. We present pilot data in utilization of dual-chamber DF-1 ICD with LBBAP lead connected to IS-1 port for cardiac resynchronization therapy.

Inclusion criteria: QRS duration more than 150 ms, LVEF<35%, symptomatic heart failure with NYHA II-III class despite 3-months guideline-directed medical therapy and LBBB. Baseline data including ECG and TTE characteristics, pacing parameters, procedural outcomes was collected. Follow-up was performed at 3 and 6 months with monitoring of 12-lead ECG and TTE with device telemetry.

LBBAP performed as previously described in EHRA consensus statement in CSP. In case of correction of the conduction system disease, LBBAP lead was connected to the pace/sense RV port. DF-1 connector plug was connected to conforming port in the generator. In patients with suboptimal criteria of LBB capture or partial correction of conduction disorder, additional CS lead implantation was performed to obtain left bundle branch area pacing optimized CRT (LOT-CRT). Total 39 patients underwent CRT implantation utilizing LBBAP. 9 (24%) patients required additional CS lead. Remained 30 (76%) patients were implanted LOT-ICD with the mean age 61,05±11,79 years. 16 (52%) males and 14 (48%) females, respectively. 21 (73%) patients had NICM, 9 (27%) had ICM.

Echocardiography showed significant improvement in left ventricle function. LVEF increased from 28,87±3,9% to 40,25±7,2%. LV end-diastolic volume and LV end-systolic volume decreased as well from baseline 216,5±75,11 to 147,6±52,3 and 163,2±69,4 to 90,7±42,2 ml respectively. Mean LVAT 83,8±14,1 ms and V6-V1 interpeak 46,8±7,3 ms. Fusion between LBBAP and native RBB conduction resulted in significant narrowing of QRS from 171,8±16 ms to 116,6±9,6 ms. LBBAP showed pacing threshold of 0,75 V±0,4, mean R-wave amplitude 12,5±5,4 mV and unipolar pacing impedance 645±185 Ohm. There were no major LBB lead related complications as lead macrodislodgement, coronary artery injuries, lead and helix damage. Septal perforation was occurred in 5 patients with successful lead repositioning, RBB trauma in 3 patients, which spontanneous resolved during obsevation period. In 3 patients we observed T-wave oversensing which caused inappropriate detection of VF without inappropriate ICD therapy.

LOT-ICD provides comparable electrical resynchronization to CRT according to worldwide data. It may be promising and cost-effective technology for patients with heart failure. Further explorations are necessary to confirm effectiveness and safety. Inappropriate sensing of ventricular arrhythmias may be important issue to define the role of LOT-ICD in future.

LOT-ICD connection