Left ventricular dyssynchrony will be assessed by echocardiography using different programming of an implantable cardioverter defibrillator.

Left ventricular dyssynchrony will be assessed by echocardiography using different programming of an implantable cardioverter defibrillator using a quadripolar left ventricular lead.

Inclusion Criteria:

• Indication for the implantation of a defibrillator with cardiac resynchronisation therapy

Exclusion Criteria:

• Cardiac surgery, acute coronary syndrome / myocardial infarction, percutaneous coronary intervention within the past 4 weeks
• Indication for coronary artery revascularisation
• Atrial fibrillation with insufficient rate control
• ASA (American Society of Anesthesiologists) class V or cardiogenic shock
• age <18 years, pregnancy, tutelage
• inability to understand the patient consent for or study refusal
• anticipated insufficient echocardiographic image quality