Left ventricular (LV) lead implantation failure was uncommon among patients undergoing planned CRT procedures, and coronary sinus access failure was the most common reason, according to a recent retrospective study published in Heart Rhythm.

Using data from the NCDR EP Device Implant Registry, Daniel J. Friedman, MD, FACC, et al., included 111,802 patients with left bundle branch block and ejection fraction ≤35% who underwent a planned CRT procedure between 2010 and 2016. They sought to determine the rate of LV lead implantation failure as well as the cause along with other factors independently associated with the complication.

Results showed that LV lead implantation failure occurred in 3.6% of patients (n=3,979), with reasons for the complication including venous access (7.5%), coronary sinus access (64.3%), tributary vein access (13.5%), coronary sinus dissection (7.6%), unacceptable threshold (4.4%) and diaphragmatic stimulation (1.7%).

The study authors also identified several significant independent predictors of LV lead implant failure such as younger age (odds ratio [OR], 1.01; 95% CI, 1.01-1.02), female sex (OR, 1.38; 95% CI, 1.29-1.47), Black race (OR, 1.44; 95% CI, 1.32-1.57), Hispanic ethnicity (OR, 1.23; 95% CI, 1.08-1.40), longer QRS duration (OR, 1.055 per 10 mins; 95% CI, 1.038-1.072 per 10 mins), obstructive sleep apnea (OR, 1.14; 95% CI, 1.04-1.24), and implantation by a physician without specialized training rather than a cardiac electrophysiologist (OR, 1.53; 95% CI, 1.34-1.76).

Study limitations included lack of endpoint adjudication for site-reported patient characteristics and outcomes data. In addition, the registry does not capture data on lead characteristics or implantation equipment from procedures where LV lead implantation failed, so the authors were unable to assess the relationship between specific leads or equipment with the likelihood of implant success.

“While the present study captures rates of technical implant success (96.4%), it does not capture the quality of the implant, which is relevant because patients with LV pacing from the apex, middle cardiac vein and anterior interventricular vein are unlikely to benefit,” state the authors.