The conventional CRT-D system consists of 3 leads in patients with Heart Failure (HF). A part of HF patients have non-impaired sinus node function and will not be stimulated in the right atrium. The implantation of the right atrial lead, which is not mandatory in these patients, harbors potential complication risks and prolongs implantation procedure. The new CRT-DX system uses 2 leads only: a right ventricular lead extended with floating RA sending dipole and a left ventricular lead. The aim of the BIO|REDUCE study is to assess the residual safety and performance aspects of the CRT-DX system within 12 months follow-up in HF patients with an indication for a CRT-D, sinus rhythm, and no need for an atrial lead implantation.

Inclusion Criteria:

• Patient is able to understand the nature of study and has provided written informed consent.
• Patient is willing and able to perform all follow up visits at the study site.
• Patient is willing and able to use the CardioMessenger® and accepts the BIOTRONIK Home Monitoring® concept.
• CRT-D is indicated according to the current ESC guidelines.
• De novo implantation with no pre-existing defibrillator or pacemaker system
• Patient is in sinus rhythm without history of persistent or permanent atrial fibrillation.
• Patient has no atrioventricular (AV) block II or III.
• Patient has no evidence of impaired sinus node function.
• Patient has no need for atrial stimulation, has a resting heart rate (HR) > 40 b.p.m and achieves a peak HR ≥100 b.p.m even under intended dosage of HR lowering medication verified by an appropriate method as clinical routine examination within 3 months prior to enrollment
• NYHA class II or III
• Patient receives guideline-based optimized medical therapy for HF including heart-rate lowering medication at the time of enrollment

Exclusion Criteria:

• Patient is pregnant or breast feeding.
• Patient is less than 18 years old.
• Patient is participating in an interventional clinical investigation.
• Life-expectancy is less than 1 year.
• Patient has tachycardia-bradycardia syndrome
• Any standard contraindication for CRT-D
• Frequent premature ventricular contractions (PVC rate > 5 %/h) examined within 3 months prior to enrollment by appropriate routine method (e.g. 24 h holter electrocardiogram)

Patients with Cardiac Resynchronization Therapy Defibrillator (CRT-D) indication according to the current guidelines, who are in sinus rhythm without history of persistent or permanent atrial fibrillation (AF) and do not require right atrial (RA) lead implantation at study enrolment.