Cardiac resynchronosation and left ventricular ejection fraction improvement with single ventricular conduction pacing system lead

Abstract Background Conduction system pacing is a new modality to obtain physiologic pacing (PP) and normal to near normal cardiac synchrony; they often obtain shorter QRS durations and they could replace the need of Bi-V (CRT) implants if LVEF improves as much with less leads implanted. Methods From our cohort of 340 physiologic pacing attempts (2019-2023), we extracted all patients (pts) with available ultrasounds before and after implants, aiming to describe the variation of Left Ventricular Ejection Fraction (LVEF) over time; all attempts, including failures were analyzed. Results A total of 146 pts completed follow-up LVEF evaluation. Pts were 36,8% females; median age was 79 +/- 8.5 years. Indications were: SSS 25%, AV block 41% (including 11 post TAVR), Pacemaker induced cardiomyopathy (PIMC) 27% and AV node ablation in 7%. Success to achieve cardiac resynchronisation (defined as a QRS shorter than 140ms and a LVAT shorter than 90ms, or 20% reduction in QRS width) was obtained in 82,6% of pts (higher success rate achieved with LBB-P: 88,4% vs 55,5% for His-P). Procedural time (pts in-out) was 88min (+/- 37min). Pts with a QRS larger than 150ms (CRT indication) were 49% of the cohort. Patients with a LVEF less than 50% accounted for 54,8% of the cohort. Mean QRS duration was 141,9ms (+/-36) pre-implant and 129,3ms (+/- 19) post implant. Mean LVEF was 43,6% (+/- 14) before implant and increased to 50,2% (+/-12) post implant for the entire cohort, in pts with CRT indication, variation persisted: mean LVEF improved from 33,2 to 43,8% and QRS duration from 172,9 to 136,8ms. Pts with less than 50% LVEF had a response rate of 75,5% (increase in LVEF from 4-41%), and 33% of patients increase their LEVF between 10-30% (deemed super responders), only one pt decrease 10% her LVEF (a His failure implant). Conclusion Cardiac resynchronisation is feasible with only one ventricular lead, potentially with longer duration of batteries and lesser costs. Response rate is similar to CRT historical controls but super responders are twice to three times higher than historical controls.