Clinical Investigation on Differences in the Magnitude of CRT Response in WOmen Versus MEN

BIOWOMEN is a study designed to compare the Cardiac Resynchronization Therapy (CRT) response rate in a Heart Failure (HF) population with an equal distribution of men and women. Different clinical variables will be collected (QRSd, Left Bundle Brunch Block (LBBB), HF etiology...) and compared in order to demonstrate that women may respond even better than men.

Prospective, non-randomized, international, open, multicenter study. Patients that comply with the inclusion and exclusion criteria will be implanted with a BIOTRONIK CRT system.

The primary objective is to study the magnitude of CRT response measured as function of increase in Left Ventricular Ejection Fraction (LVEF) in order to demonstrate a superior CRT response in women.

The Secondary main objectives are:

* To study changes in major clinical variables during a 12M FU period in men and women
* To study how Left Ventricular End Diastolic Volume (LVEDV) and Left Ventricular End Systolic Volume (LVESV) change in men and women with CRT response
* To study CRT responders and value if there are significant gender differences at baseline with regards of presence of inter/intra ventricular dyssynchrony, HF etiology (ischemic versus non-ischemic cardiomyopathy), QRS morphology (LBBB vs. RBBB) and QRSd
* Observational assessment of how key baseline clinical variables are related to the patient's CRT response, to create a possible "gender specific" response model.
* Study the relationship between QRSd (amount of dyssynchrony) and CRT response in men and women

There are no study specific requirements for the implantation procedure of the CRT device; implantation will be performed according to the routine hospital's practice.

In order to obtain an equal distribution of males and females in the study population enrolled by the site, all the inclusions should be performed consecutively (based on the normal hospital flow of CRT candidates), but the difference in the enrolment rate by gender should not exceed \> 2 by site at any time during the enrolment phase.

The study flowchart consists of a baseline assessment, implantation/pre-hospital discharge, 2 month Follow Up (FU), 6 month FU, 12 month FU, and final study.

Special assessments as echocardiography (echo), 6 minute walk test and Quality of Life test (QOL) will be performed at baseline, after 6 months and at one year follow-up.

12-lead electrocardiogram (ECG) will only be performed at baseline. Device testing, (Serious) Adverse (Device) Events ((S)A(D)E), and changes in medication will be collected during all planned study FUs throughout the duration of the study. A device interrogation outside the scheduled study FU window needs to be reported as unscheduled FU.

The timing for scheduled FUs is at 2 month, 6 month and 12 month after implantation (and pre-hospital discharge) with a time window of ± 1 month.

All the echo images and ECGs will be saved and sent to the respective Core Labs.

The estimated sample size is 494 patients: 247 men and 247 women.

Eligibility Criteria:
Inclusion Criteria:

* Indication for a "De Novo" implantation of a CRT device according to ESC Guidelines
* Understand the nature of the procedure
* Give written informed consent

Exclusion Criteria:

* CRT Device replacements
* CRT upgrades
* Permanent / Persistent Atrial Fibrillation
* Age\< 18 years
* Pregnant and breastfeeding women
* Subjects with irreversible brain damage from pre existing cerebral disease
* Subjects with acutely de compensated heart failure
* NYHA Class IV Heart Failure
* Heart transplantation six months prior to the enrolment or expected within next 3 months.
* Cardiac surgery 3 months prior to the enrolment or planned within next 3 months.
* Have a life expectancy of less than 12 months