Background: Cardiac resynchronisation therapy (CRT) reduces patient morbidity and mortality, however, nearly 30–40% of patients fail to respond. The management of these so-called CRT non-responders (who remain symptomatic and have no evidence of reverse left ventricular (LV) remodelling following epicardial CRT) remains limited with few treatment options available. Studies have shown that endocardial LV pacing is potentially superior to epicardial LV pacing since it allows faster electrical activation, is more physiological and provides a greater selection of pacing sites enabling the operator to select the optimal myocardial site without any scar. The WiSE-CRT system was developed to provide endocardial LV pacing and may be particularly useful in CRT non-responders to improve their outcomes.
Objectives: The purpose of this analysis was to determine whether the WiSE-CRT system improves patient outcomes patients previously classified as CRT non-responders.
Method: All CRT non-responders who successfully underwent the WiSE-CRT system implanted were analysed. Patients were considered CRT responders if they had evidence of left ventricular remodelling at 6 months or had an improvement in their clinical composite score (CCS) which was defined as; alive, no heart failure hospitalisations, improvement in NYHA Functional class or improvement in patient global assessment.
Results: Overall 17 patients were analysed, baseline demographics include: age of 68.2 ± 7.9 years, 94.1% male, 41.1% ischaemic aetiology, NYHA Functional class 2.8 ± 0.4, QRS duration 169.1 ± 23.8ms and left ventricular ejection fraction (LVEF) 25.6 ± 8.0%. There were no acute complications and only 1 patient developed a pocket haematoma during the follow-up period. During the follow-up period, 58.8% of patients had an improvement in their CCS, 53.3% had an improvement in left ventricular end-systolic volume (LVESV) of ≥15% and 64.7% had an absolute increase in LVEF of ≥5% or improvement in LVESV of ≥15%.
Conclusion: The management of CRT non-responders remains difficult with limited treatment options available for patients. Our analysis has shown that in this high-risk patient group, the WiSE-CRT system results in a considerable improvement in the clinical composite score and leads to reverse left ventricular remodelling. These encouraging results suggest an important role for the WiSE-CRT system in the management of CRT non-responders.