Cardiac resynchronisation therapy (CRT) is an effective treatment for patients with advanced heart failure (HF) (New York Heart Association class (NYHA) III or IV), depressed left ventricular ejection fraction (LVEF, <35%) and wide QRS complexes (>120 ms) as demonstrated in various large multicentre trials. The beneficial effects include improvement in HF symptoms, exercise capacity, and LV function, as well as less HF hospitalisations and lower mortality rates.
1 Despite these impressive results, a consistent percentage of patients show no benefit after CRT, the so-called ‘non-responders’. The prevalence of non-responders is around 30% when clinical endpoints are used (e.g. improvement in NYHA class or exercise capacity), but can be much higher, up to 50%, when echocardiographic endpoints, such as improvement in LV function or reduction in LV end-systolic volume (LVESV), are used.
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