Why Is the Group of Non-responders to Cardiac Resynchronization Therapy so Large? Some Ethical and Medical Aspects of the Topic

Abstract

The aim of this single centre study (“St. Ekaterina” Hospital) is to assess the effect of a second successful cardiac resynchronization therapy (CRT) in patients who had already had an unsuccessful implantation of a CRT system at other medical centres in Bulgaria and were defined as “non-responders”. This is a prospective observational study. The patients have previously had an unsuccessful implantation of a left ventricular (LV) lead or the latter has not been placed in the target vessel. After the successful implantation of a new LV lead in another target vessel, the post-procedure criteria for echocardiographic (EchoCG) and clinical response were monitored. Over the period 2017–2019, 18 CRT systems have been implanted in 18 patients with an average age 65±1 years with initial heart failure (HF) according to the Classification of the New York Heart Association (NYHA) class III. The average LV ejection fraction (LVEF) was 28±1%. After the successful implantation of a new LV lead, patients presented with HF class II–III and LVEF 36±1%. In the new “upgrading” procedure, 15 patients (83%) had a good clinical and EchoCG response, and two of those 15 patients were “super responders”. The remaining three patients (17%) were “poor responders”. After the good clinical and echocardiographic response to the therapy with a second successful implantation of a LV lead in another target vessel, an important question arises, whether all “non-responders” to the CRT are actually supposed to be defined as such.