Table 1 Inclusion and exclusion criteria.

Non-ischaemic, dilated cardiomyopathy

Symptomatic despite optimally-tolerated medical therapy

Impaired left ventricular systolic function (LVEF < 40%) as assessed by resting echocardiography

Exclusion Criteria

History of liver disease or liver function test measurements greater than twice the upper normal limit

Concomitant use of amiodarone, quinidine, haloperidol or selective serotonin re-uptake inhibitors that inhibit the CYP2D6 enzyme

Pre-existing evidence of peripheral neuropathy

Women of child bearing potential

Patients with any contraindication to magnetic resonance imaging such as an implantable cardiac device or claustrophobia

Obesity (BMI > 35)

Obstructive sleep apnoea