Efficacy of leadless left ventricular endocardial stimulation for non-responders to cardiac resynchronization therapy

Non-responders to conventional coronary sinus CRT represent a high-risk heart failure population with limited treatment options. Leadless LV endocardial pacing may provide benefit by delivering more physiological activation patterns, and enabling pacing from optimized LV cavity sites. We aimed to evaluate the efficacy of leadless endocardial pacing using the WiSE-CRT system in CRT non-responders.

A pooled patient-level post-hoc analysis of the SELECT-LV study, the WiSE Post-Market Registry and the SOLVE-CRT trial was performed. Multivariable regression analysis identified predictors of response to WiSE-CRT, followed by ROC analysis and subgroup analysis by degree of QRS narrowing.

The total cohort comprised of 71 patients. Complete echocardiographic data was available in 66 patients, and complete ECG data available in 45 patients. The clinical response rate (improvement in at least one NYHA class) was 46%. The "combined echocardiographic response rate" (composite of reduction in LV end-systolic volume of ≥15% or improvement in LV ejection fraction of ≥5%) was 51%. The degree of QRS reduction with WiSE-CRT compared to standard CRT was an independent predictor of combined echocardiographic response. ROC analysis generated an AUC of 0.68, with a Youden index cut-off of 19ms reduction in QRS. Subgroup analysis revealed a combined echocardiographic response rate of 70.5% above the cut-off and 38.5% below p = 0.04).

Leadless endocardial CRT is a viable treatment option for conventional CRT non-responders. The degree of QRS narrowing with LV endocardial stimulation is predictive of response. Optimizing QRS reduction when testing LV pacing sites may be beneficial in maximizing outcomes.