It's the aim of this study to investigate the impact of Right Ventricular (RV) lead position (RV-apex, His bundle area, RV-apex+His bundle area) in combination with individually optimized Left Ventricular (LV) lead placement and CRT timing on the outcome of cardiac resynchronization therapy (CRT).

Inclusion Criteria:

• Patient with indication for CRT-D: NYHA III-IV congestive heart failure, in spite of optimal medical treatment for their congestive heart failure
• LVEDD > 55 mm or > 30 mm/m² BSA
• EF < 35%
• Sinus rhythm and one of the following criteria:
• QRS >= 120 ms and PQ >= 200ms
• or
• 2nd / 3rd degree AV block
• Written informed consent

Exclusion Criteria:

• pacemaker indication (without ICD indication)
• tricuspidal valve and/or aortic valve replacement
• Indication for revascularization.
• less than 3 month after heart surgery or myocardial infarction
• hypertrophic obstructive cardiomyopathy
• intravenous catecholamine treatment
• uncorrected thyroid function
• severe kidney disorder (creatinin >2,5mg%)
• no written patient consent
• insufficient patient compliance
• participating in another study
• life expectancy < 1 year due to other severe disease
• age < 18 years
• no contraception (young women) or pregnancy