Performance at mid-term follow-up of traditional high voltage leads implanted in the left bundle branch area

Conduction system pacing (CSP) is more and more emerging as a cardiac pacing technique alternative to conventional cardiac resynchronization therapy (CRT) to treat ventricular dyssynchrony. At this very moment, only a few data are available about the implantation of a traditional high voltage (HV) lead to perform left bundle branch area (LBBA) pacing, and follow-up is very short.

The aim of our study is to evaluate the electrical performances, pacing, and defibrillator efficiency of traditional HV leads implanted in the LBBA at mid-term follow-up (up to 1 year).

14 patients (10 males, 68.8 ± 10.5 yo), with the indication for ICD/CRT-D (4 secondary prevention, 2 LBBB, 1 3rd degree AV block), were enrolled and implanted with a traditional HV lead (6.8F) in the LBBA (via a preshaped three-dimensional delivery sheath). CSP verification and defibrillation tests were performed at implantation. Patient follow-ups were performed at one week, one month, three months, six months, and twelve months reporting electrical parameters, consistency of CSP, ventricular synchrony (via echocardiographical evaluation), and efficacy of antitachycardia therapy in vivo.

All 14 patients reported, at 1-year follow-up, no change in ECG and ventricular synchrony echo parameters (Peak Strain Dispersion <60ms). Electrical parameters were also stable (mean R-wave amplitude 10.8±2.2 mV; pacing impedance 436±44 ohm, shock impedance 70±6 ohm, and pacing threshold 0.72±0.24V@0.4ms) with improving trend of R-wave amplitude and pacing threshold (with effective automatic capture management in 12 of 14 patients) and a significant reduction of pacing impedance, in comparison to acute post-implantation values. We do not report any over/undersensing or noise issues and in two patients we observed in vivo ICD effective ventricular arrhythmias termination both by antitachycardia pacing (ATP) and shock. One patient underwent pocket revision due to significant weight loss, with no further issues. No lead-related complications are reported.

Traditional HV leads could not only be safely and effectively implanted in the LBBA but are also showing excellent pacing and defibrillation performances in mid-term (up to 1 year) follow-up. Further investigations are ongoing with prolonged follow-up.