Table 1 Inclusion/exclusion criteria

A. Inclusion criteria

 ● HF with NYHA class II/III

 ● LVEF < 35% in patients on OPT for at least 3 months and candidate for ICD

 ● Patients with left ventricular contractile reserve at low-dose dobutamine stress echocardiography test

 ● QRS duration: 100–130 ms

 ● Ability and willingness to comply with study requirements

 ● Successful quadripolar LV lead implantation (only for treatment group)

B. Exclusion criteria

 ● Myocardial infarction, unstable angina within 40 days prior to enrollment

 ● Cardiac revascularization (PTCA, stent or CABG) in the 4 weeks prior to enrollment or planned for the 3 months following enrollment

 ● Cerebrovascular accident (CVA) or transient ischemic attack (TIA) in the 3 months prior to enrollment

 ● Primary valvular disease

 ● Inability to comply with the follow-up schedule

 ● Age less than 18 years

 ● Pregnancy or intention to become pregnant during the period of the investigation

 ● Classification of status 1 for cardiac transplantation or consideration for transplantation over the next 12 months

 ● Previous cardiac transplantation

 ● Life expectancy < 12 months

 ● Permanent atrial fibrillation