Table 1.

Inclusion and exclusion criteria

Inclusion criteria

Symptomatic heart failure (NYHA class II–IV despite OMT)

ECG with LBBB according to the Strauss criteria [37] or indwelling single or dual chamber pacemaker and a paced QRS ≥ 180 ms

LVEF ≤ 35%

Age ≥ 40 years

Written informed consent

Exclusion criteria

Expected lifetime < 6 months

Expected cardiac surgery within the next 6 months

Recent (< 3 months) myocardial infarction or CABG

Pregnant or lactating

NYHA New York Heart Association, OMT optimal therapy for the individual patient at the time of referral for cardiac resynchronization therapy, ECG electrocardiogram, LBBB left bundle branch block, LVEF left ventricular ejection fraction, CABG coronary artery bypass graft