The objective of this study is to assess the safety and effectiveness of the automatic atrioventricular (AV) delay and interventricular (VV) delay optimization algorithm used in the PARADYM RF SONR Cardiac Resynchronization Therapy with Defibrillation (CRT-D) device (Model 9770) in combination with the SonRtip Lead, which includes a SonR sensor in the tip of the atrial pacing lead, and compatible SmartView programming software.

This study will evaluate the effectiveness of the automatic optimization algorithm in increasing the rate of patients responding to the therapy as compared to an echocardiographic optimization method.

This study will also evaluate the safety and effectiveness of the SonRtip atrial pacing lead.

Since the introduction of cardiac resynchronization therapy (CRT) on a large scale, it has been observed that approximately 30% of recipient patients are non-responsive to therapy. This non-responsiveness can be decreased by optimizing the device programming, particularly the stimulation rate, paced and sensed atrioventricular (AV) delay, and the interventricular (VV) delay.

All CRT patients need a 100% rate of ventricular capture, but beyond this the achievement of therapy effectiveness requires the identification of the optimal pacing configuration, which varies among patients. The optimization of CRT systems, usually based on ultrasound imaging is time-consuming and the number of patients in need of multiple optimization procedures due to ventricular remodeling is growing rapidly.

The mechanical effects of a more coordinated contraction result in a shortening of the isovolumetric contraction phase and the pre-ejection time, and an increase in LV dP/dt (change in left ventricular pressure over time. The concept of measuring contractility with an implantable accelerometer was first clinically validated through a multicenter study on a rate responsive pacing system (BEST - Living from SORIN Biomedica) in 1996. This study positively demonstrates that measurement of Peak Endocardial Acceleration signal (called PEA or SonR) is feasible and reliable in the long-term, both for the purpose of rate response and as a hemodynamic monitor of cardiac function.

More recent clinical studies have demonstrated that optimal VV and AV Delays determined using algorithms based on SonR signal analysis (SonR method) are correlated with the highest hemodynamic improvement and lead to significant clinical benefit for the patients, thus reducing the rate of non-responsiveness to CRT therapy.

Therefore, automatic AV and VV delay optimization in patients with CRT devices could benefit both the patient and physician.

Inclusion Criteria:

1. Patient eligible with class I and IIa indication for implantation of a CRT-D device according to current available guidelines ;
2. Modere,Severe HF (NYHA Class III or ambulatory IV)
3. LVEF ≤ 35 %
4. LBBB: QRS ≥ 120 ms ; non-LBBB : QRS ≥ 150 ms
5. On a stable, optimal drug regimen
6. Patient is in sinus rhythm at the time of enrollment;
7. Signed and dated informed consent

Exclusion Criteria:

1. Ventricular tachyarrhythmia of transient or reversible causes such as acute myocardial infarction, digitalis intoxication, drowning, electrocution, electrolyte imbalance, hypoxia or sepsis, uncorrected at the time of the enrolment;
2. Incessant ventricular tachyarrhythmia;
3. Unstable angina, or acute MI, CABG, or PTCA within the past 4 weeks;
4. Correctable valvular disease that is the primary cause of heart failure;
5. Recent CVA or TIA (within the previous 3 months);
6. Persistent or permanent atrial arrhythmias (or cardioversion for atrial fibrillation) within the past month;
7. Post heart transplant (patients who are waiting for a heart transplant are allowed in the study);
8. Renal failure (GFR<15 ml/min/1.73m2) or on dialysis
9. Previous implant with a CRT/CRT-D device;
10. Concurrent implant with another pacemaker or ICD (previously implanted pacemaker or ICD devices or RA leads should be removed prior to implant with the Paradym RF SONR CRT-D);
11. Already included in another clinical study that could confound the results of this study;
12. Life expectancy less than 1 year;
13. Inability to understand the purpose of the study or to understand and complete the QOL questionnaire;
14. Unavailability for scheduled follow-up or refusal to cooperate;
15. Sensitivity to 1 mg dexamethasone sodium phosphate (DSP)
16. Age of less than 18 years;
17. Pregnancy
18. Drug addiction or abuse
19. Under guardianship