are in normal sinus rhythm, are not indicated for cardiac resynchronization therapy, and have a left ventricular ejection fraction ranging from 25% to 45%. CE mark Based on the results of clinical trials, cardiac contractility modulation devices are approved and available for clinical use in all European Union countries and in Australia, Turkey, India and Hong Kong, as well as in other countries that recognize CE marking for medical devices. CE indication Based on the approval of cardiac contractility modulation devices, the therapy is a treatment option for patients that are at least 18 years old who suffer from heart failure symptoms due to left ventricular systolic dysfunction (LVSD) despite adequate medical treatment. Further clinical research are under way to identify which patient group within the scope of the device approval benefits most from cardiac contractility modulation treatment. Criteria for the classification of patients with left ventricular systolic heart failure include the severity of the disease based on functional parameters (NYHA classification), the average percentage of blood volume ejected by the left ventricle with each heart beat (left ventricular ejection fraction or LVEF) and the duration of the QRS complex seen in the electrocardiogram (ECG). Most clinical studies on cardiac contractility modulation therapy have involved heart failure patients who were classified initially as NYHA Class II, III or IV and had a normal QRS duration (QRS duration ≤ 120 ms). The efficacy of cardiac contractility modulation on patients in an earlier stage of heart failure has not yet been studied. A subsequent evaluation study (subgroup analysis) has already suggested a particular patient group that responds exceptionally well to cardiac contractility modulation therapy. The patients were characterized by a disease severity of NYHA class III and a left ventricular ejection fraction of ≥ 25%. Although studies on cardiac contractility modulation therapy have focused on patients with a normal QRS duration (i.e. ≤ 120 ms), it is possible to use the therapy in patients who meet the treatment indication but who do not have a normal QRS duration. A preliminary study has previously shown that cardiac contractility modulation may be safe and effective in such patients who have not responded to cardiac resynchronization therapy (CRT). Therapeutic gap Cardiac resynchronization therapy (CRT; also known as biventricular pacing) has proven to be an effective treatment in heart failure. However, CRT is generally recommended exclusively for patients with a preserved sinus rhythm and a prolonged